sql_select.cc 206 KB
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/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */


/* mysql_select and join optimization */

#ifdef __GNUC__
#pragma implementation				// gcc: Class implementation
#endif

#include "mysql_priv.h"
#include "sql_select.h"
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#include "opt_ft.h"
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#include <m_ctype.h>
#include <hash.h>
#include <ft_global.h>
#include <assert.h>

const char *join_type_str[]={ "UNKNOWN","system","const","eq_ref","ref",
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			      "MAYBE_REF","ALL","range","index","fulltext" };
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static bool make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
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				 DYNAMIC_ARRAY *keyuse);
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static bool update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,
				JOIN_TAB *join_tab,
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                                uint tables,COND *conds,table_map table_map);
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static int sort_keyuse(KEYUSE *a,KEYUSE *b);
static void set_position(JOIN *join,uint index,JOIN_TAB *table,KEYUSE *key);
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static bool create_ref_for_key(JOIN *join, JOIN_TAB *j, KEYUSE *org_keyuse,
			       table_map used_tables);
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static void find_best_combination(JOIN *join,table_map rest_tables);
static void find_best(JOIN *join,table_map rest_tables,uint index,
		      double record_count,double read_time);
static uint cache_record_length(JOIN *join,uint index);
static double prev_record_reads(JOIN *join,table_map found_ref);
static bool get_best_combination(JOIN *join);
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static store_key *get_store_key(THD *thd,
				KEYUSE *keyuse, table_map used_tables,
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				KEY_PART_INFO *key_part, char *key_buff,
				uint maybe_null);
static bool make_simple_join(JOIN *join,TABLE *tmp_table);
static bool make_join_select(JOIN *join,SQL_SELECT *select,COND *item);
static void make_join_readinfo(JOIN *join,uint options);
static void join_free(JOIN *join);
static bool only_eq_ref_tables(JOIN *join,ORDER *order,table_map tables);
static void update_depend_map(JOIN *join);
static void update_depend_map(JOIN *join, ORDER *order);
static ORDER *remove_const(JOIN *join,ORDER *first_order,COND *cond,
			   bool *simple_order);
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static int return_zero_rows(JOIN *join, select_result *res,TABLE_LIST *tables,
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			    List<Item> &fields, bool send_row,
			    uint select_options, const char *info,
			    Item *having, Procedure *proc);
static COND *optimize_cond(COND *conds,Item::cond_result *cond_value);
static COND *remove_eq_conds(COND *cond,Item::cond_result *cond_value);
static bool const_expression_in_where(COND *conds,Item *item, Item **comp_item);
static bool open_tmp_table(TABLE *table);
static bool create_myisam_tmp_table(TABLE *table,TMP_TABLE_PARAM *param,
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				    ulong options);
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static int do_select(JOIN *join,List<Item> *fields,TABLE *tmp_table,
		     Procedure *proc);
static int sub_select_cache(JOIN *join,JOIN_TAB *join_tab,bool end_of_records);
static int sub_select(JOIN *join,JOIN_TAB *join_tab,bool end_of_records);
static int flush_cached_records(JOIN *join,JOIN_TAB *join_tab,bool skipp_last);
static int end_send(JOIN *join, JOIN_TAB *join_tab, bool end_of_records);
static int end_send_group(JOIN *join, JOIN_TAB *join_tab,bool end_of_records);
static int end_write(JOIN *join, JOIN_TAB *join_tab, bool end_of_records);
static int end_update(JOIN *join, JOIN_TAB *join_tab, bool end_of_records);
static int end_unique_update(JOIN *join,JOIN_TAB *join_tab,
			     bool end_of_records);
static int end_write_group(JOIN *join, JOIN_TAB *join_tab,
			   bool end_of_records);
static int test_if_group_changed(List<Item_buff> &list);
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static int join_read_const_table(JOIN_TAB *tab, POSITION *pos);
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static int join_read_system(JOIN_TAB *tab);
static int join_read_const(JOIN_TAB *tab);
static int join_read_key(JOIN_TAB *tab);
static int join_read_always_key(JOIN_TAB *tab);
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static int join_read_last_key(JOIN_TAB *tab);
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static int join_no_more_records(READ_RECORD *info);
static int join_read_next(READ_RECORD *info);
static int join_init_quick_read_record(JOIN_TAB *tab);
static int test_if_quick_select(JOIN_TAB *tab);
static int join_init_read_record(JOIN_TAB *tab);
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static int join_read_first(JOIN_TAB *tab);
static int join_read_next(READ_RECORD *info);
static int join_read_next_same(READ_RECORD *info);
static int join_read_last(JOIN_TAB *tab);
static int join_read_prev_same(READ_RECORD *info);
static int join_read_prev(READ_RECORD *info);
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static int join_ft_read_first(JOIN_TAB *tab);
static int join_ft_read_next(READ_RECORD *info);
static COND *make_cond_for_table(COND *cond,table_map table,
				 table_map used_table);
static Item* part_of_refkey(TABLE *form,Field *field);
static uint find_shortest_key(TABLE *table, key_map usable_keys);
static bool test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,
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				    ha_rows select_limit, bool no_changes);
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static int create_sort_index(JOIN_TAB *tab,ORDER *order,ha_rows filesort_limit,
			     ha_rows select_limit);
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static int remove_duplicates(JOIN *join,TABLE *entry,List<Item> &fields,
			     Item *having);
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static int remove_dup_with_compare(THD *thd, TABLE *entry, Field **field,
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				   ulong offset,Item *having);
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static int remove_dup_with_hash_index(THD *thd, TABLE *table,
				      uint field_count, Field **first_field,
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				      ulong key_length,Item *having);
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static int join_init_cache(THD *thd,JOIN_TAB *tables,uint table_count);
static ulong used_blob_length(CACHE_FIELD **ptr);
static bool store_record_in_cache(JOIN_CACHE *cache);
static void reset_cache(JOIN_CACHE *cache);
static void read_cached_record(JOIN_TAB *tab);
static bool cmp_buffer_with_ref(JOIN_TAB *tab);
static int setup_group(THD *thd,TABLE_LIST *tables,List<Item> &fields,
		       List<Item> &all_fields, ORDER *order, bool *hidden);
static bool setup_new_fields(THD *thd,TABLE_LIST *tables,List<Item> &fields,
			     List<Item> &all_fields,ORDER *new_order);
static ORDER *create_distinct_group(ORDER *order, List<Item> &fields);
static bool test_if_subpart(ORDER *a,ORDER *b);
static TABLE *get_sort_by_table(ORDER *a,ORDER *b,TABLE_LIST *tables);
static void calc_group_buffer(JOIN *join,ORDER *group);
static bool alloc_group_fields(JOIN *join,ORDER *group);
static bool make_sum_func_list(JOIN *join,List<Item> &fields);
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static bool change_to_use_tmp_fields(List<Item> &func);
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static bool change_refs_to_tmp_fields(THD *thd, List<Item> &func);
static void init_tmptable_sum_functions(Item_sum **func);
static void update_tmptable_sum_func(Item_sum **func,TABLE *tmp_table);
static void copy_sum_funcs(Item_sum **func_ptr);
static bool add_ref_to_table_cond(THD *thd, JOIN_TAB *join_tab);
static void init_sum_functions(Item_sum **func);
static bool update_sum_func(Item_sum **func);
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static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
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			    bool distinct, const char *message=NullS);
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static void describe_info(JOIN *join, const char *info);
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/*
  This handles SELECT with and without UNION
*/

int handle_select(THD *thd, LEX *lex, select_result *result)
{
  int res;
  register SELECT_LEX *select_lex = &lex->select_lex;
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  DBUG_ENTER("handle_select");
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#ifdef DISABLED_UNTIL_REWRITTEN_IN_4_1
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  if (lex->olap)
  {
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    SELECT_LEX *sl, *sl_next;
    int error;
    for (sl= &select_lex; sl; sl=sl_next)
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    {
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      sl_next=sl->next;				// Save if sl->next changes
      if (sl->olap != UNSPECIFIED_OLAP_TYPE)
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      {
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	if ((error=handle_olaps(lex,sl)))
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	  DBUG_RETURN(error);
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	lex->last_selects->next=sl_next;
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      }
    }
    lex->select = select_lex;
  }
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#endif /* DISABLED_UNTIL_REWRITTEN_IN_4_1 */
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  if (select_lex->next)
    res=mysql_union(thd,lex,result);
  else
    res=mysql_select(thd,(TABLE_LIST*) select_lex->table_list.first,
		     select_lex->item_list,
		     select_lex->where,
		     (ORDER*) select_lex->order_list.first,
		     (ORDER*) select_lex->group_list.first,
		     select_lex->having,
		     (ORDER*) lex->proc_list.first,
		     select_lex->options | thd->options,
		     result);
  if (res && result)
    result->abort();
  delete result;
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  DBUG_RETURN(res);
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}


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/*****************************************************************************
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  Check fields, find best join, do the select and output fields.
  mysql_select assumes that all tables are already opened
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*****************************************************************************/

int
mysql_select(THD *thd,TABLE_LIST *tables,List<Item> &fields,COND *conds,
	     ORDER *order, ORDER *group,Item *having,ORDER *proc_param,
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	     ulong select_options,select_result *result)
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{
  TABLE		*tmp_table;
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  int		error, tmp_error;
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  bool		need_tmp,hidden_group_fields;
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  bool		simple_order,simple_group,no_order, skip_sort_order;
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  ha_rows	select_limit;
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  Item::cond_result cond_value;
  SQL_SELECT	*select;
  DYNAMIC_ARRAY keyuse;
  JOIN		join;
  Procedure	*procedure;
  List<Item>	all_fields(fields);
  bool		select_distinct;
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  SELECT_LEX *cur_sel = thd->lex.select;
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  DBUG_ENTER("mysql_select");

  /* Check that all tables, fields, conds and order are ok */

  select_distinct=test(select_options & SELECT_DISTINCT);
  tmp_table=0;
  select=0;
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  no_order=skip_sort_order=0;
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  bzero((char*) &keyuse,sizeof(keyuse));
  thd->proc_info="init";
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  thd->used_tables=0;				// Updated by setup_fields
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  if (setup_tables(tables) ||
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      setup_fields(thd,tables,fields,1,&all_fields,1) ||
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      setup_conds(thd,tables,&conds) ||
      setup_order(thd,tables,fields,all_fields,order) ||
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      setup_group(thd,tables,fields,all_fields,group,&hidden_group_fields))
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    DBUG_RETURN(-1);				/* purecov: inspected */

  if (having)
  {
    thd->where="having clause";
    thd->allow_sum_func=1;
    if (having->fix_fields(thd,tables) || thd->fatal_error)
      DBUG_RETURN(-1);				/* purecov: inspected */
    if (having->with_sum_func)
      having->split_sum_func(all_fields);
  }
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  if (setup_ftfuncs(thd)) /* should be after having->fix_fields */
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    DBUG_RETURN(-1);
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  /*
    Check if one one uses a not constant column with group functions
    and no GROUP BY.
    TODO:  Add check of calculation of GROUP functions and fields:
	   SELECT COUNT(*)+table.col1 from table1;
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  */
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  join.table=0;
  join.tables=0;
  {
    if (!group)
    {
      uint flag=0;
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      List_iterator_fast<Item> it(fields);
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      Item *item;
      while ((item= it++))
      {
	if (item->with_sum_func)
	  flag|=1;
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	else if (!(flag & 2) && !item->const_item())
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	  flag|=2;
      }
      if (flag == 3)
      {
	my_error(ER_MIX_OF_GROUP_FUNC_AND_FIELDS,MYF(0));
	DBUG_RETURN(-1);
      }
    }
    TABLE_LIST *table;
    for (table=tables ; table ; table=table->next)
      join.tables++;
  }
  procedure=setup_procedure(thd,proc_param,result,fields,&error);
  if (error)
    DBUG_RETURN(-1);				/* purecov: inspected */
  if (procedure)
  {
    if (setup_new_fields(thd,tables,fields,all_fields,procedure->param_fields))
    {						/* purecov: inspected */
      delete procedure;				/* purecov: inspected */
      DBUG_RETURN(-1);				/* purecov: inspected */
    }
    if (procedure->group)
    {
      if (!test_if_subpart(procedure->group,group))
      {						/* purecov: inspected */
	my_message(0,"Can't handle procedures with differents groups yet",
		   MYF(0));			/* purecov: inspected */
	delete procedure;			/* purecov: inspected */
	DBUG_RETURN(-1);			/* purecov: inspected */
      }
    }
#ifdef NOT_NEEDED
    else if (!group && procedure->flags & PROC_GROUP)
    {
      my_message(0,"Select must have a group with this procedure",MYF(0));
      delete procedure;
      DBUG_RETURN(-1);
    }
#endif
    if (order && (procedure->flags & PROC_NO_SORT))
    { /* purecov: inspected */
      my_message(0,"Can't use order with this procedure",MYF(0)); /* purecov: inspected */
      delete procedure; /* purecov: inspected */
      DBUG_RETURN(-1); /* purecov: inspected */
    }
  }

  /* Init join struct */
  join.thd=thd;
  join.lock=thd->lock;
  join.join_tab=0;
  join.tmp_table_param.copy_field=0;
  join.sum_funcs=0;
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  join.send_records=join.found_records=join.examined_rows=0;
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  join.tmp_table_param.end_write_records= HA_POS_ERROR;
  join.first_record=join.sort_and_group=0;
  join.select_options=select_options;
  join.result=result;
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  count_field_types(&join.tmp_table_param,all_fields,0);
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  join.const_tables=0;
  join.having=0;
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  join.do_send_rows = 1;
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  join.group= group != 0;
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  join.row_limit= ((select_distinct || order || group) ? HA_POS_ERROR :
		   thd->select_limit);
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#ifdef RESTRICTED_GROUP
  if (join.sum_func_count && !group && (join.func_count || join.field_count))
  {
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    my_message(ER_WRONG_SUM_SELECT,ER(ER_WRONG_SUM_SELECT),MYF(0));
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    delete procedure;
    DBUG_RETURN(-1);
  }
#endif
  if (!procedure && result->prepare(fields))
  {						/* purecov: inspected */
    DBUG_RETURN(-1);				/* purecov: inspected */
  }

#ifdef HAVE_REF_TO_FIELDS			// Not done yet
  /* Add HAVING to WHERE if possible */
  if (having && !group && ! join.sum_func_count)
  {
    if (!conds)
    {
      conds=having;
      having=0;
    }
    else if ((conds=new Item_cond_and(conds,having)))
    {
      conds->fix_fields(thd,tables);
      conds->change_ref_to_fields(thd,tables);
      having=0;
    }
  }
#endif

  conds=optimize_cond(conds,&cond_value);
  if (thd->fatal_error)				// Out of memory
  {
    delete procedure;
    DBUG_RETURN(0);
  }
  if (cond_value == Item::COND_FALSE || !thd->select_limit)
  {					/* Impossible cond */
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    error=return_zero_rows(&join, result, tables, fields,
			   join.tmp_table_param.sum_func_count != 0 && !group,
			   select_options,"Impossible WHERE",having,
			   procedure);
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    delete procedure;
    DBUG_RETURN(error);
  }

  /* Optimize count(*), min() and max() */
  if (tables && join.tmp_table_param.sum_func_count && ! group)
  {
    int res;
    if ((res=opt_sum_query(tables, all_fields, conds)))
    {
      if (res < 0)
      {
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	error=return_zero_rows(&join, result, tables, fields, !group,
			       select_options,"No matching min/max row",
			       having,procedure);
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	delete procedure;
	DBUG_RETURN(error);
      }
      if (select_options & SELECT_DESCRIBE)
      {
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	describe_info(&join, "Select tables optimized away");
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	delete procedure;
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	DBUG_RETURN(error);
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      }
      tables=0;					// All tables resolved
    }
  }
  if (!tables)
  {						// Only test of functions
    error=0;
    if (select_options & SELECT_DESCRIBE)
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      describe_info(&join, "No tables used");
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    else
    {
      result->send_fields(fields,1);
      if (!having || having->val_int())
      {
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	if (join.do_send_rows && result->send_data(fields))
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	{
	  result->send_error(0,NullS);		/* purecov: inspected */
	  error=1;
	}
	else
	  error=(int) result->send_eof();
      }
      else
	error=(int) result->send_eof();
    }
    delete procedure;
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    DBUG_RETURN(error);
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  }

  error = -1;
  join.sort_by_table=get_sort_by_table(order,group,tables);

  /* Calculate how to do the join */
  thd->proc_info="statistics";
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  if (make_join_statistics(&join,tables,conds,&keyuse) || thd->fatal_error)
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    goto err;
  thd->proc_info="preparing";
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  result->initialize_tables(&join);
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  if (join.const_table_map != join.found_const_table_map &&
      !(select_options & SELECT_DESCRIBE))
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  {
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    error=return_zero_rows(&join,result,tables,fields,
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			   join.tmp_table_param.sum_func_count != 0 &&
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			   !group,0,"",having,procedure);
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    goto err;
  }
  if (!(thd->options & OPTION_BIG_SELECTS) &&
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      join.best_read > (double) thd->variables.max_join_size &&
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      !(select_options & SELECT_DESCRIBE))
  {						/* purecov: inspected */
    result->send_error(ER_TOO_BIG_SELECT,ER(ER_TOO_BIG_SELECT)); /* purecov: inspected */
    error= 1;					/* purecov: inspected */
    goto err;					/* purecov: inspected */
  }
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  if (join.const_tables && !thd->locked_tables &&
      !(select_options & SELECT_NO_UNLOCK))
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  {
    TABLE **table, **end;
    for (table=join.table, end=table + join.const_tables ;
	 table != end;
	 table++)
    {
      /* BDB tables require that we call index_end() before doing an unlock */
      if ((*table)->key_read)
      {
	(*table)->key_read=0;
	(*table)->file->extra(HA_EXTRA_NO_KEYREAD);
      }
      (*table)->file->index_end();
    }
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    mysql_unlock_some_tables(thd, join.table,join.const_tables);
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  }
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  if (!conds && join.outer_join)
  {
    /* Handle the case where we have an OUTER JOIN without a WHERE */
    conds=new Item_int((longlong) 1,1);	// Always true
  }
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  select=make_select(*join.table, join.const_table_map,
		     join.const_table_map,conds,&error);
  if (error)
  { /* purecov: inspected */
    error= -1; /* purecov: inspected */
    goto err; /* purecov: inspected */
  }
  if (make_join_select(&join,select,conds))
  {
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    error=return_zero_rows(&join, result, tables, fields,
			   join.tmp_table_param.sum_func_count != 0 && !group,
			   select_options,
			   "Impossible WHERE noticed after reading const tables",
			   having,procedure);
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    goto err;
  }

  error= -1;					/* if goto err */

  /* Optimize distinct away if possible */
  order=remove_const(&join,order,conds,&simple_order);
  if (group || join.tmp_table_param.sum_func_count)
  {
    if (! hidden_group_fields)
      select_distinct=0;
  }
  else if (select_distinct && join.tables - join.const_tables == 1 &&
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	   (thd->select_limit == HA_POS_ERROR ||
	    (join.select_options & OPTION_FOUND_ROWS) ||
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	    order &&
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	    !(skip_sort_order=
	      test_if_skip_sort_order(&join.join_tab[join.const_tables],
				      order, thd->select_limit,1))))
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  {
    if ((group=create_distinct_group(order,fields)))
    {
      select_distinct=0;
      no_order= !order;
      join.group=1;				// For end_write_group
    }
    else if (thd->fatal_error)			// End of memory
      goto err;
  }
  group=remove_const(&join,group,conds,&simple_group);
  if (!group && join.group)
  {
    order=0;					// The output has only one row
    simple_order=1;
  }

  calc_group_buffer(&join,group);
  join.send_group_parts=join.tmp_table_param.group_parts; /* Save org parts */
  if (procedure && procedure->group)
  {
    group=procedure->group=remove_const(&join,procedure->group,conds,
					&simple_group);
    calc_group_buffer(&join,group);
  }

  if (test_if_subpart(group,order) ||
      (!group && join.tmp_table_param.sum_func_count))
    order=0;

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  // Can't use sort on head table if using row cache
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  if (join.full_join)
  {
    if (group)
      simple_group=0;
    if (order)
      simple_order=0;
  }

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  /*
    Check if we need to create a temporary table.
    This has to be done if all tables are not already read (const tables)
    and one of the following conditions holds:
    - We are using DISTINCT (simple distinct's are already optimized away)
    - We are using an ORDER BY or GROUP BY on fields not in the first table
    - We are using different ORDER BY and GROUP BY orders
    - The user wants us to buffer the result.
  */
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  need_tmp= (join.const_tables != join.tables &&
	     ((select_distinct || !simple_order || !simple_group) ||
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	      (group && order) || 
	      test(select_options & OPTION_BUFFER_RESULT)));
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  // No cache for MATCH
  make_join_readinfo(&join,
		     (select_options & (SELECT_DESCRIBE |
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					SELECT_NO_JOIN_CACHE)) |
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		     (cur_sel->ftfunc_list.elements ? SELECT_NO_JOIN_CACHE :
		      0));
  /*
    Need to tell Innobase that to play it safe, it should fetch all
    columns of the tables: this is because MySQL may build row
    pointers for the rows, and for all columns of the primary key the
    field->query_id has not necessarily been set to thd->query_id by
    MySQL.
  */
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#ifdef HAVE_INNOBASE_DB
  if (need_tmp || select_distinct || group || order)
  {
    for (uint i_h = join.const_tables; i_h < join.tables; i_h++)
    {
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      TABLE*	  table_h = join.join_tab[i_h].table;
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      if (table_h->db_type == DB_TYPE_INNODB)
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	table_h->file->extra(HA_EXTRA_DONT_USE_CURSOR_TO_UPDATE);
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    }
  }
#endif

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  DBUG_EXECUTE("info",TEST_join(&join););
  /*
    Because filesort always does a full table scan or a quick range scan
    we must add the removed reference to the select for the table.
    We only need to do this when we have a simple_order or simple_group
    as in other cases the join is done before the sort.
    */
  if ((order || group) && join.join_tab[join.const_tables].type != JT_ALL &&
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      join.join_tab[join.const_tables].type != JT_FT &&
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      (order && simple_order || group && simple_group))
  {
    if (add_ref_to_table_cond(thd,&join.join_tab[join.const_tables]))
      goto err;
  }

  if (!(select_options & SELECT_BIG_RESULT) &&
      ((group && join.const_tables != join.tables &&
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	(!simple_group ||
	 !test_if_skip_sort_order(&join.join_tab[join.const_tables], group,
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				  thd->select_limit,0))) ||
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       select_distinct) &&
      join.tmp_table_param.quick_group && !procedure)
  {
    need_tmp=1; simple_order=simple_group=0;	// Force tmp table without sort
  }

  if (select_options & SELECT_DESCRIBE)
  {
    if (!order && !no_order)
      order=group;
    if (order &&
	(join.const_tables == join.tables ||
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	 (simple_order &&
	  test_if_skip_sort_order(&join.join_tab[join.const_tables], order,
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				  (join.select_options & OPTION_FOUND_ROWS) ?
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				  HA_POS_ERROR : thd->select_limit,0))))
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      order=0;
    select_describe(&join,need_tmp,
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		    order != 0 && !skip_sort_order,
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		    select_distinct);
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    error=0;
    goto err;
  }

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  /* Perform FULLTEXT search before all regular searches */
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  init_ftfuncs(thd,test(order));
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  /* Create a tmp table if distinct or if the sort is too complicated */
  if (need_tmp)
  {
    DBUG_PRINT("info",("Creating tmp table"));
    thd->proc_info="Creating tmp table";

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    join.tmp_table_param.hidden_field_count= (all_fields.elements -
					      fields.elements);
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    if (!(tmp_table =
	  create_tmp_table(thd,&join.tmp_table_param,all_fields,
			   ((!simple_group && !procedure &&
			     !(test_flags & TEST_NO_KEY_GROUP)) ?
			    group : (ORDER*) 0),
			   group ? 0 : select_distinct,
			   group && simple_group,
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			   (order == 0 || skip_sort_order) &&
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			   !(join.select_options & OPTION_FOUND_ROWS),
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			   join.select_options)))
      goto err;					/* purecov: inspected */

    if (having && (join.sort_and_group || (tmp_table->distinct && !group)))
      join.having=having;

    /* if group or order on first table, sort first */
    if (group && simple_group)
    {
      DBUG_PRINT("info",("Sorting for group"));
      thd->proc_info="Sorting for group";
      if (create_sort_index(&join.join_tab[join.const_tables],group,
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			    HA_POS_ERROR, HA_POS_ERROR) ||
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	  make_sum_func_list(&join,all_fields) ||
	  alloc_group_fields(&join,group))
	goto err;
      group=0;
    }
    else
    {
      if (make_sum_func_list(&join,all_fields))
	goto err;
      if (!group && ! tmp_table->distinct && order && simple_order)
      {
	DBUG_PRINT("info",("Sorting for order"));
	thd->proc_info="Sorting for order";
	if (create_sort_index(&join.join_tab[join.const_tables],order,
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			      HA_POS_ERROR, HA_POS_ERROR))
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	  goto err;				/* purecov: inspected */
	order=0;
      }
    }
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    /*
      Optimize distinct when used on some of the tables
      SELECT DISTINCT t1.a FROM t1,t2 WHERE t1.b=t2.b
      In this case we can stop scanning t2 when we have found one t1.a
    */

    if (tmp_table->distinct)
    {
      table_map used_tables= thd->used_tables;
      JOIN_TAB *join_tab=join.join_tab+join.tables-1;
      do
      {
	if (used_tables & join_tab->table->map)
	  break;
	join_tab->not_used_in_distinct=1;
      } while (join_tab-- != join.join_tab);
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      /* Optimize "select distinct b from t1 order by key_part_1 limit #" */
      if (order && skip_sort_order)
      {
	(void) test_if_skip_sort_order(&join.join_tab[join.const_tables],
				       order, thd->select_limit,0);
	order=0;
      }
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    }

    /* Copy data to the temporary table */
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    thd->proc_info="Copying to tmp table";
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    if ((tmp_error=do_select(&join,(List<Item> *) 0,tmp_table,0)))
    {
      error=tmp_error;
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      goto err;					/* purecov: inspected */
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    }
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    if (join.having)
      join.having=having=0;			// Allready done

    /* Change sum_fields reference to calculated fields in tmp_table */
    if (join.sort_and_group || tmp_table->group)
    {
      if (change_to_use_tmp_fields(all_fields))
	goto err;
      join.tmp_table_param.field_count+=join.tmp_table_param.sum_func_count+
	join.tmp_table_param.func_count;
      join.tmp_table_param.sum_func_count=join.tmp_table_param.func_count=0;
    }
    else
    {
      if (change_refs_to_tmp_fields(thd,all_fields))
	goto err;
      join.tmp_table_param.field_count+=join.tmp_table_param.func_count;
      join.tmp_table_param.func_count=0;
    }
    if (procedure)
      procedure->update_refs();
    if (tmp_table->group)
    {						// Already grouped
      if (!order && !no_order)
	order=group;				/* order by group */
      group=0;
    }

    /*
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      If we have different sort & group then we must sort the data by group
      and copy it to another tmp table
      This code is also used if we are using distinct something
      we haven't been able to store in the temporary table yet
      like SEC_TO_TIME(SUM(...)).
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    */

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    if (group && (!test_if_subpart(group,order) || select_distinct) ||
	(select_distinct &&
	 join.tmp_table_param.using_indirect_summary_function))
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    {					/* Must copy to another table */
      TABLE *tmp_table2;
      DBUG_PRINT("info",("Creating group table"));

      /* Free first data from old join */
      join_free(&join);
      if (make_simple_join(&join,tmp_table))
	goto err;
      calc_group_buffer(&join,group);
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      count_field_types(&join.tmp_table_param,all_fields,
			select_distinct && !group);
      join.tmp_table_param.hidden_field_count=(all_fields.elements-
					       fields.elements);
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      /* group data to new table */
      if (!(tmp_table2 = create_tmp_table(thd,&join.tmp_table_param,all_fields,
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					  (ORDER*) 0,
					  select_distinct && !group,
					  1, 0,
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					  join.select_options)))
	goto err;				/* purecov: inspected */
      if (group)
      {
	thd->proc_info="Creating sort index";
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	if (create_sort_index(join.join_tab,group,HA_POS_ERROR, HA_POS_ERROR) ||
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	    alloc_group_fields(&join,group))
	{
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	  free_tmp_table(thd,tmp_table2);	/* purecov: inspected */
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	  goto err;				/* purecov: inspected */
	}
	group=0;
      }
      thd->proc_info="Copying to group table";
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      tmp_error= -1;
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      if (make_sum_func_list(&join,all_fields) ||
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	  (tmp_error=do_select(&join,(List<Item> *) 0,tmp_table2,0)))
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      {
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	error=tmp_error;
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	free_tmp_table(thd,tmp_table2);
	goto err;				/* purecov: inspected */
      }
      end_read_record(&join.join_tab->read_record);
      free_tmp_table(thd,tmp_table);
      join.const_tables=join.tables;		// Mark free for join_free()
      tmp_table=tmp_table2;
      join.join_tab[0].table=0;			// Table is freed

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      if (change_to_use_tmp_fields(all_fields)) // No sum funcs anymore
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	goto err;
      join.tmp_table_param.field_count+=join.tmp_table_param.sum_func_count;
      join.tmp_table_param.sum_func_count=0;
    }

    if (tmp_table->distinct)
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      select_distinct=0;			/* Each row is unique */
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    join_free(&join);				/* Free quick selects */
    if (select_distinct && ! group)
    {
      thd->proc_info="Removing duplicates";
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      if (having)
	having->update_used_tables();
      if (remove_duplicates(&join,tmp_table,fields, having))
	goto err;				/* purecov: inspected */
      having=0;
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      select_distinct=0;
    }
    tmp_table->reginfo.lock_type=TL_UNLOCK;
    if (make_simple_join(&join,tmp_table))
      goto err;
    calc_group_buffer(&join,group);
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    count_field_types(&join.tmp_table_param,all_fields,0);
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  }
  if (procedure)
  {
    if (procedure->change_columns(fields) ||
	result->prepare(fields))
      goto err;
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    count_field_types(&join.tmp_table_param,all_fields,0);
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  }
  if (join.group || join.tmp_table_param.sum_func_count ||
      (procedure && (procedure->flags & PROC_GROUP)))
  {
    alloc_group_fields(&join,group);
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    setup_copy_fields(thd, &join.tmp_table_param,all_fields);
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    if (make_sum_func_list(&join,all_fields) || thd->fatal_error)
      goto err; /* purecov: inspected */
  }
  if (group || order)
  {
    DBUG_PRINT("info",("Sorting for send_fields"));
    thd->proc_info="Sorting result";
    /* If we have already done the group, add HAVING to sorted table */
    if (having && ! group && ! join.sort_and_group)
    {
      having->update_used_tables();	// Some tables may have been const
      JOIN_TAB *table=&join.join_tab[join.const_tables];
      table_map used_tables= join.const_table_map | table->table->map;

      Item* sort_table_cond=make_cond_for_table(having,used_tables,used_tables);
      if (sort_table_cond)
      {
	if (!table->select)
	  if (!(table->select=new SQL_SELECT))
	    goto err;
	if (!table->select->cond)
	  table->select->cond=sort_table_cond;
	else					// This should never happen
	  if (!(table->select->cond=new Item_cond_and(table->select->cond,
						      sort_table_cond)))
	    goto err;
	table->select_cond=table->select->cond;
	DBUG_EXECUTE("where",print_where(table->select->cond,
					 "select and having"););
	having=make_cond_for_table(having,~ (table_map) 0,~used_tables);
	DBUG_EXECUTE("where",print_where(conds,"having after sort"););
      }
    }
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    select_limit= thd->select_limit;
    if (having || group || (join.select_options & OPTION_FOUND_ROWS))
      select_limit= HA_POS_ERROR;
    else
    {
      /*
	We can abort sorting after thd->select_limit rows if we there is no
	WHERE clause for any tables after the sorted one.
      */
      JOIN_TAB *table= &join.join_tab[join.const_tables+1];
      JOIN_TAB *end_table= &join.join_tab[join.tables];
      for (; table < end_table ; table++)
      {
	if (table->select_cond)
	{
	  /* We have to sort all rows */
	  select_limit= HA_POS_ERROR;
	  break;
	}
      }
    }
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    if (create_sort_index(&join.join_tab[join.const_tables],
			  group ? group : order,
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			  select_limit, 
			  thd->select_limit))
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      goto err; /* purecov: inspected */
  }
  join.having=having;				// Actually a parameter
  thd->proc_info="Sending data";
  error=do_select(&join,&fields,NULL,procedure);

err:
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  thd->limit_found_rows = join.send_records;
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  thd->examined_row_count = join.examined_rows;
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  thd->proc_info="end";
  join.lock=0;					// It's faster to unlock later
  join_free(&join);
  thd->proc_info="end2";			// QQ
  if (tmp_table)
    free_tmp_table(thd,tmp_table);
  thd->proc_info="end3";			// QQ
  delete select;
  delete_dynamic(&keyuse);
  delete procedure;
  thd->proc_info="end4";			// QQ
  DBUG_RETURN(error);
}

/*****************************************************************************
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  Create JOIN_TABS, make a guess about the table types,
  Approximate how many records will be used in each table
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*****************************************************************************/

static ha_rows get_quick_record_count(SQL_SELECT *select,TABLE *table,
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				      key_map keys,ha_rows limit)
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{
  int error;
  DBUG_ENTER("get_quick_record_count");
  if (select)
  {
    select->head=table;
    table->reginfo.impossible_range=0;
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    if ((error=select->test_quick_select(keys,(table_map) 0,limit))
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	== 1)
      DBUG_RETURN(select->quick->records);
    if (error == -1)
    {
      table->reginfo.impossible_range=1;
      DBUG_RETURN(0);
    }
    DBUG_PRINT("warning",("Couldn't use record count on const keypart"));
  }
  DBUG_RETURN(HA_POS_ERROR);			/* This shouldn't happend */
}


static bool
make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
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		     DYNAMIC_ARRAY *keyuse_array)
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{
  int error;
  uint i,table_count,const_count,found_ref,refs,key,const_ref,eq_part;
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  table_map const_table_map,found_const_table_map,all_table_map;
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  TABLE **table_vector;
  JOIN_TAB *stat,*stat_end,*s,**stat_ref;
  SQL_SELECT *select;
  KEYUSE *keyuse,*start_keyuse;
  table_map outer_join=0;
  JOIN_TAB *stat_vector[MAX_TABLES+1];
  DBUG_ENTER("make_join_statistics");

  table_count=join->tables;
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  stat=(JOIN_TAB*) join->thd->calloc(sizeof(JOIN_TAB)*table_count);
  stat_ref=(JOIN_TAB**) join->thd->alloc(sizeof(JOIN_TAB*)*MAX_TABLES);
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  table_vector=(TABLE**) join->thd->alloc(sizeof(TABLE*)*(table_count*2));
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  if (!stat || !stat_ref || !table_vector)
    DBUG_RETURN(1);				// Eom /* purecov: inspected */
  select=0;

  join->best_ref=stat_vector;

  stat_end=stat+table_count;
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  const_table_map=found_const_table_map=all_table_map=0;
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  const_count=0;

  for (s=stat,i=0 ; tables ; s++,tables=tables->next,i++)
  {
    TABLE *table;
    stat_vector[i]=s;
    table_vector[i]=s->table=table=tables->table;
    table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);// record count
    table->quick_keys=0;
    table->reginfo.join_tab=s;
    table->reginfo.not_exists_optimize=0;
    bzero((char*) table->const_key_parts, sizeof(key_part_map)*table->keys);
    all_table_map|= table->map;
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    s->join=join;
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    s->info=0;					// For describe
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    if ((s->on_expr=tables->on_expr))
    {
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      /* Left join */
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      if (!table->file->records)
      {						// Empty table
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	s->key_dependent=s->dependent=0;	// Ignore LEFT JOIN depend.
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	set_position(join,const_count++,s,(KEYUSE*) 0);
	continue;
      }
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      s->key_dependent=s->dependent=
	s->on_expr->used_tables() & ~(table->map);
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      if (table->outer_join & JOIN_TYPE_LEFT)
	s->dependent|=stat_vector[i-1]->dependent | table_vector[i-1]->map;
      if (tables->outer_join & JOIN_TYPE_RIGHT)
	s->dependent|=tables->next->table->map;
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      outer_join|=table->map;
      continue;
    }
    if (tables->straight)			// We don't have to move this
      s->dependent= table_vector[i-1]->map | stat_vector[i-1]->dependent;
    else
      s->dependent=(table_map) 0;
    s->key_dependent=(table_map) 0;
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    if ((table->system || table->file->records <= 1) && ! s->dependent &&
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	!(table->file->table_flags() & HA_NOT_EXACT_COUNT) &&
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        !table->fulltext_searched)
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    {
      set_position(join,const_count++,s,(KEYUSE*) 0);
    }
  }
  stat_vector[i]=0;
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  join->outer_join=outer_join;
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  /*
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    If outer join: Re-arrange tables in stat_vector so that outer join
    tables are after all tables it is dependent of.
    For example: SELECT * from A LEFT JOIN B ON B.c=C.c, C WHERE A.C=C.C
    Will shift table B after table C.
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  */
  if (outer_join)
  {
    table_map used_tables=0L;
    for (i=0 ; i < join->tables-1 ; i++)
    {
      if (stat_vector[i]->dependent & ~used_tables)
      {
	JOIN_TAB *save= stat_vector[i];
	uint j;
	for (j=i+1;
	     j < join->tables && stat_vector[j]->dependent & ~used_tables;
	     j++)
	{
	  JOIN_TAB *tmp=stat_vector[j];		// Move element up
	  stat_vector[j]=save;
	  save=tmp;
	}
	if (j == join->tables)
	{
	  join->tables=0;			// Don't use join->table
	  my_error(ER_WRONG_OUTER_JOIN,MYF(0));
	  DBUG_RETURN(1);
	}
	stat_vector[i]=stat_vector[j];
	stat_vector[j]=save;
      }
      used_tables|= stat_vector[i]->table->map;
    }
  }

  if (conds || outer_join)
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    if (update_ref_and_keys(join->thd,keyuse_array,stat,join->tables,
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                            conds,~outer_join))
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      DBUG_RETURN(1);

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  /* Read tables with 0 or 1 rows (system tables) */
  join->const_table_map=const_table_map;

  for (POSITION *p_pos=join->positions, *p_end=p_pos+const_count;
       p_pos < p_end ;
       p_pos++)
  {
    int tmp;
    s= p_pos->table;
    s->type=JT_SYSTEM;
    join->const_table_map|=s->table->map;
    if ((tmp=join_read_const_table(s, p_pos)))
    {
      if (tmp > 0)
	DBUG_RETURN(1);			// Fatal error
    }
    else
      found_const_table_map|= s->table->map;
  }

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  /* loop until no more const tables are found */
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  int ref_changed;
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  do
  {
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    ref_changed = 0;
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    found_ref=0;
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    /*
      We only have to loop from stat_vector + const_count as
      set_position() will move all const_tables first in stat_vector
    */

    for (JOIN_TAB **pos=stat_vector+const_count ; (s= *pos) ; pos++)
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    {
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      TABLE *table=s->table;
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      if (s->dependent)				// If dependent on some table
      {
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	// All dep. must be constants
	if (s->dependent & ~(join->const_table_map))
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	  continue;
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	if (table->file->records <= 1L &&
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	    !(table->file->table_flags() & HA_NOT_EXACT_COUNT))
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	{					// system table
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	  int tmp;
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	  s->type=JT_SYSTEM;
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	  join->const_table_map|=table->map;
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	  set_position(join,const_count++,s,(KEYUSE*) 0);
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	  if ((tmp=join_read_const_table(s,join->positions+const_count-1)))
	  {
	    if (tmp > 0)
	      DBUG_RETURN(1);			// Fatal error
	  }
	  else
	    found_const_table_map|= table->map;
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	  continue;
	}
      }
      /* check if table can be read by key or table only uses const refs */
      if ((keyuse=s->keyuse))
      {
	s->type= JT_REF;
	while (keyuse->table == table)
	{
	  start_keyuse=keyuse;
	  key=keyuse->key;
	  s->keys|= (key_map) 1 << key;		// QQ: remove this ?

	  refs=const_ref=eq_part=0;
	  do
	  {
	    if (keyuse->val->type() != Item::NULL_ITEM)
	    {
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	      if (!((~join->const_table_map) & keyuse->used_tables))
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		const_ref|= (key_map) 1 << keyuse->keypart;
	      else
		refs|=keyuse->used_tables;
	      eq_part|= (uint) 1 << keyuse->keypart;
	    }
	    keyuse++;
	  } while (keyuse->table == table && keyuse->key == key);

	  if (eq_part == PREV_BITS(uint,table->key_info[key].key_parts) &&
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	      (table->key_info[key].flags & HA_NOSAME) &&
              !table->fulltext_searched)
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	  {
	    if (const_ref == eq_part)
	    {					// Found everything for ref.
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	      int tmp;
	      ref_changed = 1;
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	      s->type=JT_CONST;
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	      join->const_table_map|=table->map;
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	      set_position(join,const_count++,s,start_keyuse);
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	      if (create_ref_for_key(join, s, start_keyuse,
				     join->const_table_map))
		DBUG_RETURN(1);
	      if ((tmp=join_read_const_table(s,
					     join->positions+const_count-1)))
	      {
		if (tmp > 0)
		  DBUG_RETURN(1);			// Fatal error
	      }
	      else
		found_const_table_map|= table->map;
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	      break;
	    }
	    else
	      found_ref|= refs;		// Table is const if all refs are const
	  }
	}
      }
    }
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  } while (join->const_table_map & found_ref && ref_changed);
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  /* Calc how many (possible) matched records in each table */

  for (s=stat ; s < stat_end ; s++)
  {
    if (s->type == JT_SYSTEM || s->type == JT_CONST)
    {
      /* Only one matching row */
      s->found_records=s->records=s->read_time=1; s->worst_seeks=1.0;
      continue;
    }
    /* Approximate found rows and time to read them */
    s->found_records=s->records=s->table->file->records;
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    s->read_time=(ha_rows) s->table->file->scan_time();
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    /*
      Set a max range of how many seeks we can expect when using keys
      This was (s->read_time*5), but this was too low with small rows
    */
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    s->worst_seeks= (double) s->found_records / 5;
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    if (s->worst_seeks < 2.0)			// Fix for small tables
      s->worst_seeks=2.0;

    /* if (s->type == JT_EQ_REF)
      continue; */
    if (s->const_keys)
    {
      ha_rows records;
      if (!select)
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	select=make_select(s->table, join->const_table_map,
			   join->const_table_map,
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			   and_conds(conds,s->on_expr),&error);
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      records=get_quick_record_count(select,s->table, s->const_keys,
				     join->row_limit);
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      s->quick=select->quick;
      s->needed_reg=select->needed_reg;
      select->quick=0;
      if (records != HA_POS_ERROR)
      {
	s->found_records=records;
	s->read_time= (ha_rows) (s->quick ? s->quick->read_time : 0.0);
      }
    }
  }
  delete select;

  /* Find best combination and return it */
  join->join_tab=stat;
  join->map2table=stat_ref;
  join->table= join->all_tables=table_vector;
  join->const_tables=const_count;
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  join->found_const_table_map=found_const_table_map;
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  if (join->const_tables != join->tables)
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    find_best_combination(join,all_table_map & ~join->const_table_map);
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  else
  {
    memcpy((gptr) join->best_positions,(gptr) join->positions,
	   sizeof(POSITION)*join->const_tables);
    join->best_read=1.0;
  }
  DBUG_RETURN(get_best_combination(join));
}


/*****************************************************************************
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  Check with keys are used and with tables references with tables
  Updates in stat:
	  keys	     Bitmap of all used keys
	  const_keys Bitmap of all keys with may be used with quick_select
	  keyuse     Pointer to possible keys
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*****************************************************************************/

typedef struct key_field_t {		// Used when finding key fields
  Field		*field;
  Item		*val;			// May be empty if diff constant
  uint		level,const_level;	// QQ: Remove const_level
  bool		eq_func;
  bool		exists_optimize;
} KEY_FIELD;


/* merge new key definitions to old ones, remove those not used in both */

static KEY_FIELD *
merge_key_fields(KEY_FIELD *start,KEY_FIELD *new_fields,KEY_FIELD *end,
		 uint and_level)
{
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  DBUG_ENTER("merge_key_fields");

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  if (start == new_fields)
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    DBUG_RETURN(start);				// Impossible or
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  if (new_fields == end)
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    DBUG_RETURN(start);				// No new fields, skip all
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  KEY_FIELD *first_free=new_fields;

  /* Mark all found fields in old array */
  for (; new_fields != end ; new_fields++)
  {
    for (KEY_FIELD *old=start ; old != first_free ; old++)
    {
      if (old->field == new_fields->field)
      {
	if (new_fields->val->used_tables())
	{
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	  if (old->val->eq(new_fields->val, old->field->binary()))
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	  {
	    old->level=old->const_level=and_level;
	    old->exists_optimize&=new_fields->exists_optimize;
	  }
	}
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	else if (old->val->eq(new_fields->val, old->field->binary()) &&
		 old->eq_func && new_fields->eq_func)
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	{
	  old->level=old->const_level=and_level;
	  old->exists_optimize&=new_fields->exists_optimize;
	}
	else					// Impossible; remove it
	{
	  if (old == --first_free)		// If last item
	    break;
	  *old= *first_free;			// Remove old value
	  old--;				// Retry this value
	}
      }
    }
  }
  /* Remove all not used items */
  for (KEY_FIELD *old=start ; old != first_free ;)
  {
    if (old->level != and_level && old->const_level != and_level)
    {						// Not used in all levels
      if (old == --first_free)
	break;
      *old= *first_free;			// Remove old value
      continue;
    }
    old++;
  }
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  DBUG_RETURN(first_free);
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}


static void
add_key_field(KEY_FIELD **key_fields,uint and_level,
	      Field *field,bool eq_func,Item *value,
	      table_map usable_tables)
{
  bool exists_optimize=0;
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  DBUG_ENTER("add_key_field");

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  if (!(field->flags & PART_KEY_FLAG))
  {
    // Don't remove column IS NULL on a LEFT JOIN table
    if (!eq_func || !value || value->type() != Item::NULL_ITEM ||
	!field->table->maybe_null || field->null_ptr)
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      DBUG_VOID_RETURN;					// Not a key. Skip it
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    exists_optimize=1;
  }
  else
  {
    table_map used_tables=0;
    if (value && (used_tables=value->used_tables()) &
	(field->table->map | RAND_TABLE_BIT))
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      DBUG_VOID_RETURN;
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    if (!(usable_tables & field->table->map))
    {
      if (!eq_func || !value || value->type() != Item::NULL_ITEM ||
	  !field->table->maybe_null || field->null_ptr)
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	DBUG_VOID_RETURN;					// Can't use left join optimize
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      exists_optimize=1;
    }
    else
    {
      JOIN_TAB *stat=field->table->reginfo.join_tab;
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      key_map possible_keys= (field->key_start &
			      field->table->keys_in_use_for_query);
      stat[0].keys|= possible_keys;		// Add possible keys
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      if (!value)
      {						// Probably BETWEEN or IN
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	stat[0].const_keys |= possible_keys;
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	DBUG_VOID_RETURN;					// Can't be used as eq key
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      }

      /* Save the following cases:
	 Field op constant
	 Field LIKE constant where constant doesn't start with a wildcard
	 Field = field2 where field2 is in a different table
	 Field op formula
	 Field IS NULL
	 Field IS NOT NULL
      */
      stat[0].key_dependent|=used_tables;
      if (value->const_item())
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	stat[0].const_keys |= possible_keys;
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      /* We can't always use indexes when comparing a string index to a
	 number. cmp_type() is checked to allow compare of dates to numbers */
      if (!eq_func ||
	  field->result_type() == STRING_RESULT &&
	  value->result_type() != STRING_RESULT &&
	  field->cmp_type() != value->result_type())
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	DBUG_VOID_RETURN;
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    }
  }
  /* Store possible eq field */
  (*key_fields)->field=field;
  (*key_fields)->eq_func=eq_func;
  (*key_fields)->val=value;
  (*key_fields)->level=(*key_fields)->const_level=and_level;
  (*key_fields)->exists_optimize=exists_optimize;
  (*key_fields)++;
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  DBUG_VOID_RETURN;
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}


static void
add_key_fields(JOIN_TAB *stat,KEY_FIELD **key_fields,uint *and_level,
	       COND *cond, table_map usable_tables)
{
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  DBUG_ENTER("add_key_fields");

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  if (cond->type() == Item_func::COND_ITEM)
  {
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    List_iterator_fast<Item> li(*((Item_cond*) cond)->argument_list());
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    KEY_FIELD *org_key_fields= *key_fields;

    if (((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
    {
      Item *item;
      while ((item=li++))
	add_key_fields(stat,key_fields,and_level,item,usable_tables);
      for (; org_key_fields != *key_fields ; org_key_fields++)
      {
	if (org_key_fields->const_level == org_key_fields->level)
	  org_key_fields->const_level=org_key_fields->level= *and_level;
	else
	  org_key_fields->const_level= *and_level;
      }
    }
    else
    {
      (*and_level)++;
      add_key_fields(stat,key_fields,and_level,li++,usable_tables);
      Item *item;
      while ((item=li++))
      {
	KEY_FIELD *start_key_fields= *key_fields;
	(*and_level)++;
	add_key_fields(stat,key_fields,and_level,item,usable_tables);
	*key_fields=merge_key_fields(org_key_fields,start_key_fields,
				     *key_fields,++(*and_level));
      }
    }
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    DBUG_VOID_RETURN;
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  }
  /* If item is of type 'field op field/constant' add it to key_fields */

  if (cond->type() != Item::FUNC_ITEM)
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    DBUG_VOID_RETURN;
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  Item_func *cond_func= (Item_func*) cond;
  switch (cond_func->select_optimize()) {
  case Item_func::OPTIMIZE_NONE:
    break;
  case Item_func::OPTIMIZE_KEY:
    if (cond_func->key_item()->type() == Item::FIELD_ITEM)
      add_key_field(key_fields,*and_level,
		    ((Item_field*) (cond_func->key_item()))->field,
		    0,(Item*) 0,usable_tables);
    break;
  case Item_func::OPTIMIZE_OP:
  {
    bool equal_func=(cond_func->functype() == Item_func::EQ_FUNC ||
		     cond_func->functype() == Item_func::EQUAL_FUNC);

    if (cond_func->arguments()[0]->type() == Item::FIELD_ITEM)
    {
      add_key_field(key_fields,*and_level,
		    ((Item_field*) (cond_func->arguments()[0]))->field,
		    equal_func,
		    (cond_func->arguments()[1]),usable_tables);
    }
    if (cond_func->arguments()[1]->type() == Item::FIELD_ITEM &&
	cond_func->functype() != Item_func::LIKE_FUNC)
    {
      add_key_field(key_fields,*and_level,
		    ((Item_field*) (cond_func->arguments()[1]))->field,
		    equal_func,
		    (cond_func->arguments()[0]),usable_tables);
    }
    break;
  }
  case Item_func::OPTIMIZE_NULL:
    /* column_name IS [NOT] NULL */
    if (cond_func->arguments()[0]->type() == Item::FIELD_ITEM)
    {
      add_key_field(key_fields,*and_level,
		    ((Item_field*) (cond_func->arguments()[0]))->field,
		    cond_func->functype() == Item_func::ISNULL_FUNC,
		    new Item_null, usable_tables);
    }
    break;
  }
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  DBUG_VOID_RETURN;
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}

/*
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  Add all keys with uses 'field' for some keypart
  If field->and_level != and_level then only mark key_part as const_part
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*/

static uint
max_part_bit(key_map bits)
{
  uint found;
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  DBUG_ENTER("max_part_bit");

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  for (found=0; bits & 1 ; found++,bits>>=1) ;
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  DBUG_RETURN(found);
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}


static void
add_key_part(DYNAMIC_ARRAY *keyuse_array,KEY_FIELD *key_field)
{
  Field *field=key_field->field;
  TABLE *form= field->table;
  KEYUSE keyuse;
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  DBUG_ENTER("add_key_part");
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  if (key_field->eq_func && !key_field->exists_optimize)
  {
    for (uint key=0 ; key < form->keys ; key++)
    {
      if (!(form->keys_in_use_for_query & (((key_map) 1) << key)))
	continue;
      if (form->key_info[key].flags & HA_FULLTEXT)
	continue;    // ToDo: ft-keys in non-ft queries.   SerG

      uint key_parts= (uint) form->key_info[key].key_parts;
      for (uint part=0 ; part <  key_parts ; part++)
      {
	if (field->eq(form->key_info[key].key_part[part].field))
	{
	  keyuse.table= field->table;
	  keyuse.val =  key_field->val;
	  keyuse.key =  key;
	  keyuse.keypart=part;
	  keyuse.used_tables=key_field->val->used_tables();
	  VOID(insert_dynamic(keyuse_array,(gptr) &keyuse));
	}
      }
    }
  }
  /* Mark that we can optimize LEFT JOIN */
  if (key_field->val->type() == Item::NULL_ITEM &&
      !key_field->field->real_maybe_null())
    key_field->field->table->reginfo.not_exists_optimize=1;
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  DBUG_VOID_RETURN;
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}

static void
add_ft_keys(DYNAMIC_ARRAY *keyuse_array,
            JOIN_TAB *stat,COND *cond,table_map usable_tables)
{
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  Item_func_match *cond_func=NULL;
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  DBUG_ENTER("add_ft_keys");
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  if (!cond)
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    DBUG_VOID_RETURN;
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  if (cond->type() == Item::FUNC_ITEM)
  {
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    Item_func *func=(Item_func *)cond;
    Item_func::Functype functype=  func->functype();
    if (functype == Item_func::FT_FUNC)
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      cond_func=(Item_func_match *)cond;
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    else if (func->arg_count == 2)
    {
      Item_func *arg0=(Item_func *)(func->arguments()[0]),
                *arg1=(Item_func *)(func->arguments()[1]);
      if ((functype == Item_func::GE_FUNC ||
           functype == Item_func::GT_FUNC)  &&
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           arg0->type() == Item::FUNC_ITEM          &&
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           arg0->functype() == Item_func::FT_FUNC   &&
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           arg1->const_item() && arg1->val()>0)
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        cond_func=(Item_func_match *) arg0;
      else if ((functype == Item_func::LE_FUNC ||
                functype == Item_func::LT_FUNC)  &&
                arg1->type() == Item::FUNC_ITEM          &&
                arg1->functype() == Item_func::FT_FUNC   &&
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                arg0->const_item() && arg0->val()>0)
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        cond_func=(Item_func_match *) arg1;
    }
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  }
  else if (cond->type() == Item::COND_ITEM)
  {
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    List_iterator_fast<Item> li(*((Item_cond*) cond)->argument_list());
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    if (((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
    {
      Item *item;
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      /*
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         I'm (Sergei) too lazy to implement proper recursive descent here,
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         and anyway, nobody will use such a stupid queries
         that will require it :-)
         May be later...
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      */
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      while ((item=li++))
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      {
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        if (item->type() == Item::FUNC_ITEM &&
            ((Item_func *)item)->functype() == Item_func::FT_FUNC)
        {
          cond_func=(Item_func_match *)item;
          break;
        }
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      }
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    }
  }

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  if (!cond_func || cond_func->key == NO_SUCH_KEY)
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    DBUG_VOID_RETURN;
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  KEYUSE keyuse;

  keyuse.table= cond_func->table;
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  keyuse.val =  cond_func;
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  keyuse.key =  cond_func->key;
#define FT_KEYPART   (MAX_REF_PARTS+10)
  keyuse.keypart=FT_KEYPART;
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  keyuse.used_tables=cond_func->key_item()->used_tables();
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  VOID(insert_dynamic(keyuse_array,(gptr) &keyuse));
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  DBUG_VOID_RETURN;
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}

static int
sort_keyuse(KEYUSE *a,KEYUSE *b)
{
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  DBUG_ENTER("sort_keyuse");

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  if (a->table->tablenr != b->table->tablenr)
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    DBUG_RETURN((int) (a->table->tablenr - b->table->tablenr));
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  if (a->key != b->key)
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    DBUG_RETURN((int) (a->key - b->key));
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  if (a->keypart != b->keypart)
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    DBUG_RETURN((int) (a->keypart - b->keypart));
  DBUG_RETURN(test(a->used_tables) - test(b->used_tables));	// Place const first
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}


/*
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  Update keyuse array with all possible keys we can use to fetch rows
  join_tab is a array in tablenr_order
  stat is a reference array in 'prefered' order.
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*/

static bool
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update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
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		    uint tables, COND *cond, table_map normal_tables)
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{
  uint	and_level,i,found_eq_constant;
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  DBUG_ENTER("update_ref_and_keys");
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  {
    KEY_FIELD *key_fields,*end;

    if (!(key_fields=(KEY_FIELD*)
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	  thd->alloc(sizeof(key_fields[0])*(thd->cond_count+1)*2)))
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      DBUG_RETURN(TRUE); /* purecov: inspected */
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    and_level=0; end=key_fields;
    if (cond)
      add_key_fields(join_tab,&end,&and_level,cond,normal_tables);
    for (i=0 ; i < tables ; i++)
    {
      if (join_tab[i].on_expr)
      {
	add_key_fields(join_tab,&end,&and_level,join_tab[i].on_expr,
		       join_tab[i].table->map);
      }
    }
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    if (my_init_dynamic_array(keyuse,sizeof(KEYUSE),20,64))
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      DBUG_RETURN(TRUE);
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    /* fill keyuse with found key parts */
    for (KEY_FIELD *field=key_fields ; field != end ; field++)
      add_key_part(keyuse,field);
  }

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  if (thd->lex.select->ftfunc_list.elements)
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  {
    add_ft_keys(keyuse,join_tab,cond,normal_tables);
  }

  /*
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    Remove ref if there is a keypart which is a ref and a const.
    Remove keyparts without previous keyparts.
    Special treatment for ft-keys.
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  */
  if (keyuse->elements)
  {
    KEYUSE end,*prev,*save_pos,*use;

    qsort(keyuse->buffer,keyuse->elements,sizeof(KEYUSE),
	  (qsort_cmp) sort_keyuse);

    bzero((char*) &end,sizeof(end));		/* Add for easy testing */
    VOID(insert_dynamic(keyuse,(gptr) &end));

    use=save_pos=dynamic_element(keyuse,0,KEYUSE*);
    prev=&end;
    found_eq_constant=0;
    for (i=0 ; i < keyuse->elements-1 ; i++,use++)
    {
      if (!use->used_tables)
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	use->table->const_key_parts[use->key] |=
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	  (key_part_map) 1 << use->keypart;
      if (use->keypart != FT_KEYPART)
      {
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	if (use->key == prev->key && use->table == prev->table)
	{
	  if (prev->keypart+1 < use->keypart ||
	      prev->keypart == use->keypart && found_eq_constant)
	    continue;				/* remove */
	}
	else if (use->keypart != 0)		// First found must be 0
	  continue;
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      }

      *save_pos= *use;
      prev=use;
      found_eq_constant= !use->used_tables;
      /* Save ptr to first use */
      if (!use->table->reginfo.join_tab->keyuse)
	use->table->reginfo.join_tab->keyuse=save_pos;
      use->table->reginfo.join_tab->checked_keys|= (key_map) 1 << use->key;
      save_pos++;
    }
    i=(uint) (save_pos-(KEYUSE*) keyuse->buffer);
    VOID(set_dynamic(keyuse,(gptr) &end,i));
    keyuse->elements=i;
  }
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  DBUG_RETURN(FALSE);
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}


/*****************************************************************************
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  Go through all combinations of not marked tables and find the one
  which uses least records
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*****************************************************************************/

/* Save const tables first as used tables */

static void
set_position(JOIN *join,uint idx,JOIN_TAB *table,KEYUSE *key)
{
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  DBUG_ENTER("set_position");

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  join->positions[idx].table= table;
  join->positions[idx].key=key;
  join->positions[idx].records_read=1.0;	/* This is a const table */

  /* Move the const table as down as possible in best_ref */
  JOIN_TAB **pos=join->best_ref+idx+1;
  JOIN_TAB *next=join->best_ref[idx];
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  for (;next != table ; pos++)
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  {
    JOIN_TAB *tmp=pos[0];
    pos[0]=next;
    next=tmp;
  }
  join->best_ref[idx]=table;
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  DBUG_VOID_RETURN;
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}


static void
find_best_combination(JOIN *join, table_map rest_tables)
{
  DBUG_ENTER("find_best_combination");
  join->best_read=DBL_MAX;
  find_best(join,rest_tables, join->const_tables,1.0,0.0);
  DBUG_VOID_RETURN;
}


static void
find_best(JOIN *join,table_map rest_tables,uint idx,double record_count,
	  double read_time)
{
  ulong rec;
  double tmp;
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  THD *thd= current_thd;
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  DBUG_ENTER("find_best");
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  if (!rest_tables)
  {
    DBUG_PRINT("best",("read_time: %g  record_count: %g",read_time,
		       record_count));

    read_time+=record_count/(double) TIME_FOR_COMPARE;
    if (join->sort_by_table &&
	join->sort_by_table != join->positions[join->const_tables].table->table)
      read_time+=record_count;			// We have to make a temp table
    if (read_time < join->best_read)
    {
      memcpy((gptr) join->best_positions,(gptr) join->positions,
	     sizeof(POSITION)*idx);
      join->best_read=read_time;
    }
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    DBUG_VOID_RETURN;
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  }
  if (read_time+record_count/(double) TIME_FOR_COMPARE >= join->best_read)
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    DBUG_VOID_RETURN;					/* Found better before */
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  JOIN_TAB *s;
  double best_record_count=DBL_MAX,best_read_time=DBL_MAX;
  for (JOIN_TAB **pos=join->best_ref+idx ; (s=*pos) ; pos++)
  {
    table_map real_table_bit=s->table->map;
    if ((rest_tables & real_table_bit) && !(rest_tables & s->dependent))
    {
      double best,best_time,records;
      best=best_time=records=DBL_MAX;
      KEYUSE *best_key=0;
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      uint best_max_key_part=0;
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      if (s->keyuse)
      {						/* Use key if possible */
	TABLE *table=s->table;
	KEYUSE *keyuse,*start_key=0;
	double best_records=DBL_MAX;
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	uint max_key_part=0;
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	/* Test how we can use keys */
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	rec= s->records/MATCHING_ROWS_IN_OTHER_TABLE;  /* Assumed records/key */
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	for (keyuse=s->keyuse ; keyuse->table == table ;)
	{
	  key_map found_part=0;
	  table_map found_ref=0;
	  uint key=keyuse->key;
	  KEY *keyinfo=table->key_info+key;
          bool ft_key=(keyuse->keypart == FT_KEYPART);

	  start_key=keyuse;
	  do
	  {
            uint keypart=keyuse->keypart;
	    do
	    {
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              if (!ft_key)
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              {
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		table_map map;
		if (!(rest_tables & keyuse->used_tables))
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		{
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		  found_part|= (key_part_map) 1 << keypart;
		  found_ref|= keyuse->used_tables;
		}
		/*
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		  If we find a ref, assume this table matches a proportional
		  part of this table.
		  For example 100 records matching a table with 5000 records
		  gives 5000/100 = 50 records per key
		  Constant tables are ignored and to avoid bad matches,
		  we don't make rec less than 100.
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		*/
		if (keyuse->used_tables &
		    (map=(keyuse->used_tables & ~join->const_table_map)))
		{
		  uint tablenr;
		  for (tablenr=0 ; ! (map & 1) ; map>>=1, tablenr++) ;
		  if (map == 1)			// Only one table
		  {
		    TABLE *tmp_table=join->all_tables[tablenr];
		    if (rec > tmp_table->file->records && rec > 100)
		      rec=max(tmp_table->file->records,100);
		  }
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		}
              }
	      keyuse++;
	    } while (keyuse->table == table && keyuse->key == key &&
		     keyuse->keypart == keypart);
	  } while (keyuse->table == table && keyuse->key == key);

	  /*
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	    Assume that that each key matches a proportional part of table.
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	  */
          if (!found_part && !ft_key)
	    continue;				// Nothing usable found
	  if (rec == 0)
	    rec=1L;				// Fix for small tables

          /*
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	    ft-keys require special treatment
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          */
          if (ft_key)
          {
            /*
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	      Really, there should be records=0.0 (yes!)
	      but 1.0 would be probably safer
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            */
            tmp=prev_record_reads(join,found_ref);
            records=1.0;
          }
          else
          {
	  /*
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	    Check if we found full key
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	  */
	  if (found_part == PREV_BITS(uint,keyinfo->key_parts))
	  {				/* use eq key */
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	    max_key_part= (uint) ~0;
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	    if ((keyinfo->flags & (HA_NOSAME | HA_NULL_PART_KEY)) == HA_NOSAME)
	    {
	      tmp=prev_record_reads(join,found_ref);
	      records=1.0;
	    }
	    else
	    {
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	      if (!found_ref)
	      {					// We found a const key
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		if (table->quick_keys & ((key_map) 1 << key))
		  records= (double) table->quick_rows[key];
		else
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		  records= (double) s->records/rec; // quick_range couldn't use key!
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	      }
	      else
	      {
		if (!(records=keyinfo->rec_per_key[keyinfo->key_parts-1]))
		{				// Prefere longer keys
		  records=
		    ((double) s->records / (double) rec *
		     (1.0 +
		      ((double) (table->max_key_length-keyinfo->key_length) /
		       (double) table->max_key_length)));
		  if (records < 2.0)
		    records=2.0;		// Can't be as good as a unique
		}
	      }
	      if (table->used_keys & ((key_map) 1 << key))
	      {
		/* we can use only index tree */
		uint keys_per_block= table->file->block_size/2/
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		  (keyinfo->key_length+table->file->ref_length)+1;
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		tmp=(record_count*(records+keys_per_block-1)/
		     keys_per_block);
	      }
	      else
		tmp=record_count*min(records,s->worst_seeks);
	    }
	  }
	  else
	  {
	    /*
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	      Use as much key-parts as possible and a uniq key is better
	      than a not unique key
	      Set tmp to (previous record count) * (records / combination)
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	    */
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	    if ((found_part & 1) &&
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		!(table->file->index_flags(key) & HA_ONLY_WHOLE_INDEX))
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	    {
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	      max_key_part=max_part_bit(found_part);
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	      /*
		Check if quick_range could determinate how many rows we
		will match
	      */
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	      if (table->quick_keys & ((key_map) 1 << key) &&
		  table->quick_key_parts[key] <= max_key_part)
		tmp=records= (double) table->quick_rows[key];
	      else
	      {
		/* Check if we have statistic about the distribution */
		if ((records=keyinfo->rec_per_key[max_key_part-1]))
		  tmp=records;
		else
		{
		  /*
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		    Assume that the first key part matches 1% of the file
		    and that the hole key matches 10 (dupplicates) or 1
		    (unique) records.
		    Assume also that more key matches proportionally more
		    records
		    This gives the formula:
		    records= (x * (b-a) + a*c-b)/(c-1)
		    
		    b = records matched by whole key
		    a = records matched by first key part (10% of all records?)
		    c = number of key parts in key
		    x = used key parts (1 <= x <= c)
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		  */
		  double rec_per_key;
		  if (!(rec_per_key=(double)
			keyinfo->rec_per_key[keyinfo->key_parts-1]))
		    rec_per_key=(double) s->records/rec+1;

		  if (!s->records)
		    tmp=0;
		  else if (rec_per_key/(double) s->records >= 0.01)
		    tmp=rec_per_key;
		  else
		  {
		    double a=s->records*0.01;
		    tmp=(max_key_part * (rec_per_key - a) +
			 a*keyinfo->key_parts - rec_per_key)/
		      (keyinfo->key_parts-1);
		    set_if_bigger(tmp,1.0);
		  }
		  records=(ulong) tmp;
		}
	      }
	      if (table->used_keys & ((key_map) 1 << key))
	      {
		/* we can use only index tree */
		uint keys_per_block= table->file->block_size/2/
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		  (keyinfo->key_length+table->file->ref_length)+1;
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		tmp=record_count*(tmp+keys_per_block-1)/keys_per_block;
	      }
	      else
		tmp=record_count*min(tmp,s->worst_seeks);
	    }
	    else
	      tmp=best_time;			// Do nothing
	  }
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          } /* not ft_key */
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	  if (tmp < best_time - records/(double) TIME_FOR_COMPARE)
	  {
	    best_time=tmp + records/(double) TIME_FOR_COMPARE;
	    best=tmp;
	    best_records=records;
	    best_key=start_key;
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	    best_max_key_part=max_key_part;
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	  }
	}
	records=best_records;
      }
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      /*
	Don't test table scan if it can't be better.
	Prefer key lookup if we would use the same key for scanning.
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	Don't do a table scan on InnoDB tables, if we can read the used
	parts of the row from any of the used index.
	This is because table scans uses index and we would not win
	anything by using a table scan.
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      */
      if ((records >= s->found_records || best > s->read_time) &&
	  !(s->quick && best_key && s->quick->index == best_key->key &&
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	    best_max_key_part >= s->table->quick_key_parts[best_key->key]) &&
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	  !((s->table->file->table_flags() & HA_TABLE_SCAN_ON_INDEX) &&
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	    s->table->used_keys && best_key))
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      {						// Check full join
	if (s->on_expr)
	{
	  tmp=s->found_records;			// Can't use read cache
	}
	else
	{
	  tmp=(double) s->read_time;
	  /* Calculate time to read through cache */
	  tmp*=(1.0+floor((double) cache_record_length(join,idx)*
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			  record_count /
			  (double) thd->variables.join_buff_size));
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	}
	if (best == DBL_MAX ||
	    (tmp  + record_count/(double) TIME_FOR_COMPARE*s->found_records <
	     best + record_count/(double) TIME_FOR_COMPARE*records))
	{
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	  /*
	    If the table has a range (s->quick is set) make_join_select()
	    will ensure that this will be used
	  */
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	  best=tmp;
	  records=s->found_records;
	  best_key=0;
	}
      }
      join->positions[idx].records_read=(double) records;
      join->positions[idx].key=best_key;
      join->positions[idx].table= s;
      if (!best_key && idx == join->const_tables &&
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	  s->table == join->sort_by_table &&
	  join->thd->select_limit >= records)
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	join->sort_by_table= (TABLE*) 1;	// Must use temporary table

     /*
	Go to the next level only if there hasn't been a better key on
	this level! This will cut down the search for a lot simple cases!
       */
      double current_record_count=record_count*records;
      double current_read_time=read_time+best;
      if (best_record_count > current_record_count ||
	  best_read_time > current_read_time ||
	  idx == join->const_tables && s->table == join->sort_by_table)
      {
	if (best_record_count >= current_record_count &&
	    best_read_time >= current_read_time &&
	    (!(s->key_dependent & rest_tables) || records < 2.0))
	{
	  best_record_count=current_record_count;
	  best_read_time=current_read_time;
	}
	swap(JOIN_TAB*,join->best_ref[idx],*pos);
	find_best(join,rest_tables & ~real_table_bit,idx+1,
		  current_record_count,current_read_time);
	swap(JOIN_TAB*,join->best_ref[idx],*pos);
      }
      if (join->select_options & SELECT_STRAIGHT_JOIN)
	break;				// Don't test all combinations
    }
  }
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  DBUG_VOID_RETURN;
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}


/*
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  Find how much space the prevous read not const tables takes in cache
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*/

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static void calc_used_field_length(THD *thd, JOIN_TAB *join_tab)
{
  uint null_fields,blobs,fields,rec_length;
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  DBUG_ENTER("calc_used_field_length");

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  null_fields=blobs=fields=rec_length=0;

  Field **f_ptr,*field;
  for (f_ptr=join_tab->table->field ; (field= *f_ptr) ; f_ptr++)
  {
    if (field->query_id == thd->query_id)
    {
      uint flags=field->flags;
      fields++;
      rec_length+=field->pack_length();
      if (flags & BLOB_FLAG)
	blobs++;
      if (!(flags & NOT_NULL_FLAG))
	null_fields++;
    }
  }
  if (null_fields)
    rec_length+=(join_tab->table->null_fields+7)/8;
  if (join_tab->table->maybe_null)
    rec_length+=sizeof(my_bool);
  if (blobs)
  {
    uint blob_length=(uint) (join_tab->table->file->mean_rec_length-
			     (join_tab->table->reclength- rec_length));
    rec_length+=(uint) max(4,blob_length);
  }
  join_tab->used_fields=fields;
  join_tab->used_fieldlength=rec_length;
  join_tab->used_blobs=blobs;
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}


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static uint
cache_record_length(JOIN *join,uint idx)
{
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  uint length=0;
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  JOIN_TAB **pos,**end;
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  THD *thd=join->thd;
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  DBUG_ENTER("cache_record_length");
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  for (pos=join->best_ref+join->const_tables,end=join->best_ref+idx ;
       pos != end ;
       pos++)
  {
    JOIN_TAB *join_tab= *pos;
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    if (!join_tab->used_fieldlength)		/* Not calced yet */
      calc_used_field_length(thd, join_tab);
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    length+=join_tab->used_fieldlength;
  }
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  DBUG_RETURN(length);
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}


static double
prev_record_reads(JOIN *join,table_map found_ref)
{
  double found=1.0;
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  DBUG_ENTER("prev_record_reads");
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  for (POSITION *pos=join->positions ; found_ref ; pos++)
  {
    if (pos->table->table->map & found_ref)
    {
      found_ref&= ~pos->table->table->map;
      found*=pos->records_read;
    }
  }
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  DBUG_RETURN(found);
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}


/*****************************************************************************
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  Set up join struct according to best position.
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*****************************************************************************/

static bool
get_best_combination(JOIN *join)
{
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  uint i,tablenr;
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  table_map used_tables;
  JOIN_TAB *join_tab,*j;
  KEYUSE *keyuse;
  uint table_count;
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  THD *thd=join->thd;
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  DBUG_ENTER("get_best_combination");
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  table_count=join->tables;
  if (!(join->join_tab=join_tab=
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	(JOIN_TAB*) thd->alloc(sizeof(JOIN_TAB)*table_count)))
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    DBUG_RETURN(TRUE);
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  join->full_join=0;

  used_tables=0;
  for (j=join_tab, tablenr=0 ; tablenr < table_count ; tablenr++,j++)
  {
    TABLE *form;
    *j= *join->best_positions[tablenr].table;
    form=join->table[tablenr]=j->table;
    used_tables|= form->map;
    form->reginfo.join_tab=j;
    if (!j->on_expr)
      form->reginfo.not_exists_optimize=0;	// Only with LEFT JOIN
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    if (j->type == JT_CONST)
      continue;					// Handled in make_join_stat..

    j->ref.key = -1;
    j->ref.key_parts=0;
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    if (j->type == JT_SYSTEM)
      continue;
    if (!j->keys || !(keyuse= join->best_positions[tablenr].key))
    {
      j->type=JT_ALL;
      if (tablenr != join->const_tables)
	join->full_join=1;
    }
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    else if (create_ref_for_key(join, j, keyuse, used_tables))
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      DBUG_RETURN(TRUE);				// Something went wrong
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  }
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  for (i=0 ; i < table_count ; i++)
    join->map2table[join->join_tab[i].table->tablenr]=join->join_tab+i;
  update_depend_map(join);
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  DBUG_RETURN(0);
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}
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static bool create_ref_for_key(JOIN *join, JOIN_TAB *j, KEYUSE *org_keyuse,
			       table_map used_tables)
{
  KEYUSE *keyuse=org_keyuse;
  bool ftkey=(keyuse->keypart == FT_KEYPART);
  THD  *thd= join->thd;
  uint keyparts,length,key;
  TABLE *table;
  KEY *keyinfo;
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  DBUG_ENTER("create_ref_for_key");
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  /*
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    Use best key from find_best
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  */
  table=j->table;
  key=keyuse->key;
  keyinfo=table->key_info+key;

  if (ftkey)
  {
    Item_func_match *ifm=(Item_func_match *)keyuse->val;

    length=0;
    keyparts=1;
    ifm->join_key=1;
  }
  else
  {
    keyparts=length=0;
    do
    {
      if (!((~used_tables) & keyuse->used_tables))
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      {
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	if (keyparts == keyuse->keypart)
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	{
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	  keyparts++;
	  length+=keyinfo->key_part[keyuse->keypart].store_length;
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	}
      }
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      keyuse++;
    } while (keyuse->table == table && keyuse->key == key);
  } /* not ftkey */

  /* set up fieldref */
  keyinfo=table->key_info+key;
  j->ref.key_parts=keyparts;
  j->ref.key_length=length;
  j->ref.key=(int) key;
  if (!(j->ref.key_buff= (byte*) thd->calloc(ALIGN_SIZE(length)*2)) ||
      !(j->ref.key_copy= (store_key**) thd->alloc((sizeof(store_key*) *
						   (keyparts+1)))) ||
      !(j->ref.items=    (Item**) thd->alloc(sizeof(Item*)*keyparts)))
  {
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    DBUG_RETURN(TRUE);
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  }
  j->ref.key_buff2=j->ref.key_buff+ALIGN_SIZE(length);
  j->ref.key_err=1;
  keyuse=org_keyuse;

  store_key **ref_key=j->ref.key_copy;
  byte *key_buff=j->ref.key_buff;
  if (ftkey)
  {
    j->ref.items[0]=((Item_func*)(keyuse->val))->key_item();
    if (keyuse->used_tables)
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      DBUG_RETURN(TRUE); // not supported yet. SerG
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    j->type=JT_FT;
  }
  else
  {
    uint i;
    for (i=0 ; i < keyparts ; keyuse++,i++)
    {
      while (keyuse->keypart != i ||
	     ((~used_tables) & keyuse->used_tables))
	keyuse++;				/* Skip other parts */

      uint maybe_null= test(keyinfo->key_part[i].null_bit);
      j->ref.items[i]=keyuse->val;		// Save for cond removal
      if (!keyuse->used_tables &&
	  !(join->select_options & SELECT_DESCRIBE))
      {					// Compare against constant
	store_key_item *tmp=new store_key_item(thd,
					       keyinfo->key_part[i].field,
					       (char*)key_buff +
					       maybe_null,
					       maybe_null ?
					       (char*) key_buff : 0,
					       keyinfo->key_part[i].length,
					       keyuse->val);
	if (thd->fatal_error)
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	{
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	  DBUG_RETURN(TRUE);
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	}
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	tmp->copy();
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      }
      else
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	*ref_key++= get_store_key(thd,
				  keyuse,join->const_table_map,
				  &keyinfo->key_part[i],
				  (char*) key_buff,maybe_null);
      key_buff+=keyinfo->key_part[i].store_length;
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    }
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  } /* not ftkey */
  *ref_key=0;				// end_marker
  if (j->type == JT_FT)  /* no-op */;
  else if (j->type == JT_CONST)
    j->table->const_table=1;
  else if (((keyinfo->flags & (HA_NOSAME | HA_NULL_PART_KEY))
	    != HA_NOSAME) ||
	   keyparts != keyinfo->key_parts)
    j->type=JT_REF;				/* Must read with repeat */
  else if (ref_key == j->ref.key_copy)
  {						/* Should never be reached */
    /*
      This happen if we are using a constant expression in the ON part
      of an LEFT JOIN.
      SELECT * FROM a LEFT JOIN b ON b.key=30
      Here we should not mark the table as a 'const' as a field may
      have a 'normal' value or a NULL value.
    */
    j->type=JT_CONST;
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  }
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  else
    j->type=JT_EQ_REF;
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  DBUG_RETURN(0);
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}


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static store_key *
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get_store_key(THD *thd, KEYUSE *keyuse, table_map used_tables,
	      KEY_PART_INFO *key_part, char *key_buff, uint maybe_null)
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{
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  DBUG_ENTER("get_store_key");

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  if (!((~used_tables) & keyuse->used_tables))		// if const item
  {
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    DBUG_RETURN(new store_key_const_item(thd,
2374
				    key_part->field,
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				    key_buff + maybe_null,
				    maybe_null ? key_buff : 0,
				    key_part->length,
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				    keyuse->val));
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  }
  else if (keyuse->val->type() == Item::FIELD_ITEM)
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    DBUG_RETURN(new store_key_field(thd,
2382
			       key_part->field,
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			       key_buff + maybe_null,
			       maybe_null ? key_buff : 0,
			       key_part->length,
			       ((Item_field*) keyuse->val)->field,
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			       keyuse->val->full_name()));
  DBUG_RETURN(new store_key_item(thd,
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			    key_part->field,
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			    key_buff + maybe_null,
			    maybe_null ? key_buff : 0,
			    key_part->length,
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			    keyuse->val));
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}

/*
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  This function is only called for const items on fields which are keys
  returns 1 if there was some conversion made when the field was stored.
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*/

bool
store_val_in_field(Field *field,Item *item)
{
  THD *thd=current_thd;
  ulong cuted_fields=thd->cuted_fields;
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  DBUG_ENTER("store_val_in_field");

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  thd->count_cuted_fields=1;
  item->save_in_field(field);
  thd->count_cuted_fields=0;
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  DBUG_RETURN(cuted_fields != thd->cuted_fields);
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}


static bool
make_simple_join(JOIN *join,TABLE *tmp_table)
{
  TABLE **tableptr;
  JOIN_TAB *join_tab;
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  DBUG_ENTER("make_simple_join");
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  if (!(tableptr=(TABLE**) join->thd->alloc(sizeof(TABLE*))) ||
      !(join_tab=(JOIN_TAB*) join->thd->alloc(sizeof(JOIN_TAB))))
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    DBUG_RETURN(TRUE);
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  join->join_tab=join_tab;
  join->table=tableptr; tableptr[0]=tmp_table;
  join->tables=1;
  join->const_tables=0;
  join->const_table_map=0;
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  join->tmp_table_param.field_count= join->tmp_table_param.sum_func_count=
    join->tmp_table_param.func_count=0;
  join->tmp_table_param.copy_field=join->tmp_table_param.copy_field_end=0;
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  join->first_record=join->sort_and_group=0;
  join->sum_funcs=0;
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  join->send_records=(ha_rows) 0;
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  join->group=0;
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  join->do_send_rows = 1;
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  join->row_limit=join->thd->select_limit;
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  join_tab->cache.buff=0;			/* No cacheing */
  join_tab->table=tmp_table;
  join_tab->select=0;
  join_tab->select_cond=0;
  join_tab->quick=0;
  join_tab->type= JT_ALL;			/* Map through all records */
  join_tab->keys= (uint) ~0;			/* test everything in quick */
  join_tab->info=0;
  join_tab->on_expr=0;
  join_tab->ref.key = -1;
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  join_tab->not_used_in_distinct=0;
  join_tab->read_first_record= join_init_read_record;
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  join_tab->join=join;
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  bzero((char*) &join_tab->read_record,sizeof(join_tab->read_record));
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  tmp_table->status=0;
  tmp_table->null_row=0;
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  DBUG_RETURN(FALSE);
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}


static bool
make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
{
  DBUG_ENTER("make_join_select");
  if (select)
  {
    table_map used_tables;
    if (join->tables > 1)
      cond->update_used_tables();		// Tablenr may have changed
    {						// Check const tables
      COND *const_cond=
	make_cond_for_table(cond,join->const_table_map,(table_map) 0);
      DBUG_EXECUTE("where",print_where(const_cond,"constants"););
      if (const_cond && !const_cond->val_int())
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      {
	DBUG_PRINT("info",("Found impossible WHERE condition"));
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	DBUG_RETURN(1);				// Impossible const condition
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      }
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    }
    used_tables=(select->const_tables=join->const_table_map) | RAND_TABLE_BIT;
    for (uint i=join->const_tables ; i < join->tables ; i++)
    {
      JOIN_TAB *tab=join->join_tab+i;
      table_map current_map= tab->table->map;
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      bool use_quick_range=0;
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      used_tables|=current_map;
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      if (tab->type == JT_REF && tab->quick &&
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	  (uint) tab->ref.key == tab->quick->index &&
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	  tab->ref.key_length < tab->quick->max_used_key_length)
      {
	/* Range uses longer key;  Use this instead of ref on key */
	tab->type=JT_ALL;
	use_quick_range=1;
	tab->use_quick=1;
	tab->ref.key_parts=0;		// Don't use ref key.
	join->best_positions[i].records_read=tab->quick->records;
      }

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      COND *tmp=make_cond_for_table(cond,used_tables,current_map);
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      if (!tmp && tab->quick)
      {						// Outer join
	/*
	  Hack to handle the case where we only refer to a table
	  in the ON part of an OUTER JOIN.
	*/
	tmp=new Item_int((longlong) 1,1);	// Always true
      }
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      if (tmp)
      {
	DBUG_EXECUTE("where",print_where(tmp,tab->table->table_name););
	SQL_SELECT *sel=tab->select=(SQL_SELECT*)
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	  join->thd->memdup((gptr) select, sizeof(SQL_SELECT));
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	if (!sel)
	  DBUG_RETURN(1);			// End of memory
	tab->select_cond=sel->cond=tmp;
	sel->head=tab->table;
	if (tab->quick)
	{
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	  /* Use quick key read if it's a constant and it's not used
	     with key reading */
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	  if (tab->needed_reg == 0 && tab->type != JT_EQ_REF
	      && tab->type != JT_FT && (tab->type != JT_REF ||
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	       (uint) tab->ref.key == tab->quick->index))
	  {
	    sel->quick=tab->quick;		// Use value from get_quick_...
	    sel->quick_keys=0;
	    sel->needed_reg=0;
	  }
	  else
	  {
	    delete tab->quick;
	  }
	  tab->quick=0;
	}
	uint ref_key=(uint) sel->head->reginfo.join_tab->ref.key+1;
	if (i == join->const_tables && ref_key)
	{
	  if (tab->const_keys && tab->table->reginfo.impossible_range)
	    DBUG_RETURN(1);
	}
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	else if (tab->type == JT_ALL && ! use_quick_range)
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	{
	  if (tab->const_keys &&
	      tab->table->reginfo.impossible_range)
	    DBUG_RETURN(1);				// Impossible range
	  /*
	    We plan to scan all rows.
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	    Check again if we should use an index.
	    We could have used an column from a previous table in
	    the index if we are using limit and this is the first table
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	  */

	  if ((tab->keys & ~ tab->const_keys && i > 0) ||
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	      (tab->const_keys && i == join->const_tables &&
	       join->thd->select_limit < join->best_positions[i].records_read &&
	       !(join->select_options & OPTION_FOUND_ROWS)))
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	  {
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	    /* Join with outer join condition */
	    COND *orig_cond=sel->cond;
	    sel->cond=and_conds(sel->cond,tab->on_expr);
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	    if (sel->test_quick_select(tab->keys,
				       used_tables & ~ current_map,
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				       (join->select_options &
					OPTION_FOUND_ROWS ?
					HA_POS_ERROR :
					join->thd->select_limit)) < 0)
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	      DBUG_RETURN(1);				// Impossible range
	    sel->cond=orig_cond;
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	  }
	  else
	  {
	    sel->needed_reg=tab->needed_reg;
	    sel->quick_keys=0;
	  }
	  if ((sel->quick_keys | sel->needed_reg) & ~tab->checked_keys)
	  {
	    tab->keys=sel->quick_keys | sel->needed_reg;
	    tab->use_quick= (sel->needed_reg &&
			     (!select->quick_keys ||
			      (select->quick &&
			       (select->quick->records >= 100L)))) ?
	      2 : 1;
	    sel->read_tables= used_tables;
	  }
	  if (i != join->const_tables && tab->use_quick != 2)
	  {					/* Read with cache */
	    if ((tmp=make_cond_for_table(cond,
					 join->const_table_map |
					 current_map,
					 current_map)))
	    {
	      DBUG_EXECUTE("where",print_where(tmp,"cache"););
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	      tab->cache.select=(SQL_SELECT*)
		join->thd->memdup((gptr) sel, sizeof(SQL_SELECT));
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	      tab->cache.select->cond=tmp;
	      tab->cache.select->read_tables=join->const_table_map;
	    }
	  }
	}
      }
    }
  }
  DBUG_RETURN(0);
}


static void
make_join_readinfo(JOIN *join,uint options)
{
  uint i;
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  SELECT_LEX *select_lex = &(join->thd->lex.select_lex);
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  DBUG_ENTER("make_join_readinfo");

  for (i=join->const_tables ; i < join->tables ; i++)
  {
    JOIN_TAB *tab=join->join_tab+i;
    TABLE *table=tab->table;
    tab->read_record.table= table;
    tab->read_record.file=table->file;
    tab->next_select=sub_select;		/* normal select */
    switch (tab->type) {
    case JT_SYSTEM:				// Only happens with left join
      table->status=STATUS_NO_RECORD;
      tab->read_first_record= join_read_system;
      tab->read_record.read_record= join_no_more_records;
      break;
    case JT_CONST:				// Only happens with left join
      table->status=STATUS_NO_RECORD;
      tab->read_first_record= join_read_const;
      tab->read_record.read_record= join_no_more_records;
      break;
    case JT_EQ_REF:
      table->status=STATUS_NO_RECORD;
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      if (tab->select)
      {
	delete tab->select->quick;
	tab->select->quick=0;
      }
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      delete tab->quick;
      tab->quick=0;
      table->file->index_init(tab->ref.key);
      tab->read_first_record= join_read_key;
      tab->read_record.read_record= join_no_more_records;
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      if (table->used_keys & ((key_map) 1 << tab->ref.key) &&
	  !table->no_keyread)
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      {
	table->key_read=1;
	table->file->extra(HA_EXTRA_KEYREAD);
      }
      break;
    case JT_REF:
      table->status=STATUS_NO_RECORD;
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      if (tab->select)
      {
	delete tab->select->quick;
	tab->select->quick=0;
      }
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      delete tab->quick;
      tab->quick=0;
      table->file->index_init(tab->ref.key);
      tab->read_first_record= join_read_always_key;
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      tab->read_record.read_record= join_read_next_same;
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      if (table->used_keys & ((key_map) 1 << tab->ref.key) &&
	  !table->no_keyread)
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      {
	table->key_read=1;
	table->file->extra(HA_EXTRA_KEYREAD);
      }
      break;
    case JT_FT:
      table->status=STATUS_NO_RECORD;
      table->file->index_init(tab->ref.key);
      tab->read_first_record= join_ft_read_first;
      tab->read_record.read_record= join_ft_read_next;
      break;
    case JT_ALL:
      /*
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	If previous table use cache
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      */
      table->status=STATUS_NO_RECORD;
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      if (i != join->const_tables && !(options & SELECT_NO_JOIN_CACHE) &&
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	  tab->use_quick != 2 && !tab->on_expr)
      {
	if ((options & SELECT_DESCRIBE) ||
	    !join_init_cache(join->thd,join->join_tab+join->const_tables,
			     i-join->const_tables))
	{
	  tab[-1].next_select=sub_select_cache; /* Patch previous */
	}
      }
      /* These init changes read_record */
      if (tab->use_quick == 2)
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      {
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	select_lex->options|=QUERY_NO_GOOD_INDEX_USED;
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	tab->read_first_record= join_init_quick_read_record;
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	statistic_increment(select_range_check_count, &LOCK_status);
      }
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      else
      {
	tab->read_first_record= join_init_read_record;
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	if (i == join->const_tables)
	{
	  if (tab->select && tab->select->quick)
	  {
	    statistic_increment(select_range_count, &LOCK_status);
	  }
	  else
	  {
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	    select_lex->options|=QUERY_NO_INDEX_USED;
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	    statistic_increment(select_scan_count, &LOCK_status);
	  }
	}
	else
	{
	  if (tab->select && tab->select->quick)
	  {
	    statistic_increment(select_full_range_join_count, &LOCK_status);
	  }
	  else
	  {
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	    select_lex->options|=QUERY_NO_INDEX_USED;
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	    statistic_increment(select_full_join_count, &LOCK_status);
	  }
	}
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	if (!table->no_keyread)
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	{
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	  if (tab->select && tab->select->quick &&
	      table->used_keys & ((key_map) 1 << tab->select->quick->index))
	  {
	    table->key_read=1;
	    table->file->extra(HA_EXTRA_KEYREAD);
	  }
	  else if (table->used_keys && ! (tab->select && tab->select->quick))
	  {					// Only read index tree
	    tab->index=find_shortest_key(table, table->used_keys);
	    tab->table->file->index_init(tab->index);
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	    tab->read_first_record= join_read_first;
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	    tab->type=JT_NEXT;		// Read with index_first / index_next
	  }
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	}
      }
      break;
    default:
      DBUG_PRINT("error",("Table type %d found",tab->type)); /* purecov: deadcode */
      break;					/* purecov: deadcode */
    case JT_UNKNOWN:
    case JT_MAYBE_REF:
      abort();					/* purecov: deadcode */
    }
  }
  join->join_tab[join->tables-1].next_select=0; /* Set by do_select */
  DBUG_VOID_RETURN;
}


static void
join_free(JOIN *join)
{
  JOIN_TAB *tab,*end;
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  DBUG_ENTER("join_free");
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  if (join->table)
  {
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    /*
      Only a sorted table may be cached.  This sorted table is always the
      first non const table in join->table
    */
    if (join->tables > join->const_tables) // Test for not-const tables
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      free_io_cache(join->table[join->const_tables]);
    for (tab=join->join_tab,end=tab+join->tables ; tab != end ; tab++)
    {
      delete tab->select;
      delete tab->quick;
      x_free(tab->cache.buff);
      if (tab->table)
      {
	if (tab->table->key_read)
	{
	  tab->table->key_read=0;
	  tab->table->file->extra(HA_EXTRA_NO_KEYREAD);
	}
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	/* Don't free index if we are using read_record */
	if (!tab->read_record.table)
	  tab->table->file->index_end();
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      }
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      end_read_record(&tab->read_record);
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    }
    join->table=0;
  }
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  /*
    We are not using tables anymore
    Unlock all tables. We may be in an INSERT .... SELECT statement.
  */
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  if (join->lock && join->thd->lock &&
      !(join->select_options & SELECT_NO_UNLOCK))
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  {
    mysql_unlock_read_tables(join->thd, join->lock);// Don't free join->lock
    join->lock=0;
  }
  join->group_fields.delete_elements();
  join->tmp_table_param.copy_funcs.delete_elements();
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  if (join->tmp_table_param.copy_field)		// Because of bug in ecc
    delete [] join->tmp_table_param.copy_field;
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  join->tmp_table_param.copy_field=0;
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  DBUG_VOID_RETURN;
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}


/*****************************************************************************
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  Remove the following expressions from ORDER BY and GROUP BY:
  Constant expressions
  Expression that only uses tables that are of type EQ_REF and the reference
  is in the ORDER list or if all refereed tables are of the above type.

  In the following, the X field can be removed:
  SELECT * FROM t1,t2 WHERE t1.a=t2.a ORDER BY t1.a,t2.X
  SELECT * FROM t1,t2,t3 WHERE t1.a=t2.a AND t2.b=t3.b ORDER BY t1.a,t3.X

  These can't be optimized:
  SELECT * FROM t1,t2 WHERE t1.a=t2.a ORDER BY t2.X,t1.a
  SELECT * FROM t1,t2 WHERE t1.a=t2.a AND t1.b=t2.b ORDER BY t1.a,t2.c
  SELECT * FROM t1,t2 WHERE t1.a=t2.a ORDER BY t2.b,t1.a
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*****************************************************************************/

static bool
eq_ref_table(JOIN *join, ORDER *start_order, JOIN_TAB *tab)
{
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  DBUG_ENTER("eq_ref_table");

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  if (tab->cached_eq_ref_table)			// If cached
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    DBUG_RETURN(tab->eq_ref_table);
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  tab->cached_eq_ref_table=1;
  if (tab->type == JT_CONST)			// We can skip const tables
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    DBUG_RETURN((tab->eq_ref_table=1));		/* purecov: inspected */
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  if (tab->type != JT_EQ_REF)
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    DBUG_RETURN((tab->eq_ref_table=0));		// We must use this
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  Item **ref_item=tab->ref.items;
  Item **end=ref_item+tab->ref.key_parts;
  uint found=0;
  table_map map=tab->table->map;

  for (; ref_item != end ; ref_item++)
  {
    if (! (*ref_item)->const_item())
    {						// Not a const ref
      ORDER *order;
      for (order=start_order ; order ; order=order->next)
      {
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	if ((*ref_item)->eq(order->item[0],0))
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	  break;
      }
      if (order)
      {
	found++;
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	DBUG_ASSERT(!(order->used & map));
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	order->used|=map;
	continue;				// Used in ORDER BY
      }
      if (!only_eq_ref_tables(join,start_order, (*ref_item)->used_tables()))
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	DBUG_RETURN((tab->eq_ref_table=0));
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    }
  }
  /* Check that there was no reference to table before sort order */
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  for (; found && start_order ; start_order=start_order->next)
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  {
    if (start_order->used & map)
    {
      found--;
      continue;
    }
    if (start_order->depend_map & map)
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      DBUG_RETURN((tab->eq_ref_table=0));
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  }
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  DBUG_RETURN(tab->eq_ref_table=1);
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}


static bool
only_eq_ref_tables(JOIN *join,ORDER *order,table_map tables)
{
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  DBUG_ENTER("only_eq_ref_tables");

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  if (specialflag &  SPECIAL_SAFE_MODE)
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    DBUG_RETURN(0);			// skip this optimize /* purecov: inspected */
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  for (JOIN_TAB **tab=join->map2table ; tables ; tab++, tables>>=1)
  {
    if (tables & 1 && !eq_ref_table(join, order, *tab))
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      DBUG_RETURN(0);
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  }
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  DBUG_RETURN(1);
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}


/* Update the dependency map for the tables */

static void update_depend_map(JOIN *join)
{
  JOIN_TAB *join_tab=join->join_tab, *end=join_tab+join->tables;
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  DBUG_ENTER("update_depend_map");
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  for (; join_tab != end ; join_tab++)
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  {
    TABLE_REF *ref= &join_tab->ref;
    table_map depend_map=0;
    Item **item=ref->items;
    uint i;
    for (i=0 ; i < ref->key_parts ; i++,item++)
      depend_map|=(*item)->used_tables();
    ref->depend_map=depend_map;
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    for (JOIN_TAB **tab=join->map2table;
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	 depend_map ;
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	 tab++,depend_map>>=1 )
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    {
      if (depend_map & 1)
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	ref->depend_map|=(*tab)->ref.depend_map;
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    }
  }
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  DBUG_VOID_RETURN;
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}


/* Update the dependency map for the sort order */

static void update_depend_map(JOIN *join, ORDER *order)
{
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  DBUG_ENTER("update_depend_map");

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  for (; order ; order=order->next)
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  {
    table_map depend_map;
    order->item[0]->update_used_tables();
    order->depend_map=depend_map=order->item[0]->used_tables();
    if (!(order->depend_map & RAND_TABLE_BIT))	// Not item_sum() or RAND()
    {
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      for (JOIN_TAB **tab=join->map2table;
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	   depend_map ;
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	   tab++, depend_map>>=1)
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      {
	if (depend_map & 1)
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	  order->depend_map|=(*tab)->ref.depend_map;
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      }
    }
  }
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  DBUG_VOID_RETURN;
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}


/*
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  simple_order is set to 1 if sort_order only uses fields from head table
  and the head table is not a LEFT JOIN table
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*/

static ORDER *
remove_const(JOIN *join,ORDER *first_order, COND *cond, bool *simple_order)
{
  DBUG_ENTER("remove_const");
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  if (join->tables == join->const_tables)
    DBUG_RETURN(0);					// No need to sort
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  ORDER *order,**prev_ptr;
  table_map first_table= join->join_tab[join->const_tables].table->map;
  table_map not_const_tables= ~join->const_table_map;
  table_map ref;
  prev_ptr= &first_order;
  *simple_order= join->join_tab[join->const_tables].on_expr ? 0 : 1;

  /* NOTE: A variable of not_const_tables ^ first_table; breaks gcc 2.7 */

  update_depend_map(join, first_order);
  for (order=first_order; order ; order=order->next)
  {
    table_map order_tables=order->item[0]->used_tables();
    if (order->item[0]->with_sum_func)
      *simple_order=0;				// Must do a temp table to sort
    else if (!(order_tables & not_const_tables))
    {
      DBUG_PRINT("info",("removing: %s", order->item[0]->full_name()));
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      continue;					// skip const item
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    }
    else
    {
      if (order_tables & RAND_TABLE_BIT)
	*simple_order=0;
      else
      {
	Item *comp_item=0;
	if (cond && const_expression_in_where(cond,order->item[0], &comp_item))
	{
	  DBUG_PRINT("info",("removing: %s", order->item[0]->full_name()));
	  continue;
	}
	if ((ref=order_tables & (not_const_tables ^ first_table)))
	{
	  if (only_eq_ref_tables(join,first_order,ref))
	  {
	    DBUG_PRINT("info",("removing: %s", order->item[0]->full_name()));
	    continue;
	  }
	  *simple_order=0;			// Must do a temp table to sort
	}
      }
    }
    *prev_ptr= order;				// use this entry
    prev_ptr= &order->next;
  }
  *prev_ptr=0;
  if (!first_order)				// Nothing to sort/group
    *simple_order=1;
  DBUG_PRINT("exit",("simple_order: %d",(int) *simple_order));
  DBUG_RETURN(first_order);
}

3013

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static int
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return_zero_rows(JOIN *join, select_result *result,TABLE_LIST *tables,
		 List<Item> &fields, bool send_row, uint select_options,
		 const char *info, Item *having, Procedure *procedure)
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{
  DBUG_ENTER("return_zero_rows");

  if (select_options & SELECT_DESCRIBE)
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  {
    describe_info(join, info);
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    DBUG_RETURN(0);
  }
  if (procedure)
  {
    if (result->prepare(fields))		// This hasn't been done yet
      DBUG_RETURN(-1);
  }
  if (send_row)
  {
    for (TABLE_LIST *table=tables; table ; table=table->next)
      mark_as_null_row(table->table);		// All fields are NULL
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    if (having && having->val_int() == 0)
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      send_row=0;
  }
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  if (!(result->send_fields(fields,1)))
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  {
    if (send_row)
      result->send_data(fields);
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    if (tables)				// Not from do_select()
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    {
      /* Close open cursors */
      for (TABLE_LIST *table=tables; table ; table=table->next)
	table->table->file->index_end();
    }
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    result->send_eof();				// Should be safe
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  }
  DBUG_RETURN(0);
}


static void clear_tables(JOIN *join)
{
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  DBUG_ENTER("clear_tables");

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  for (uint i=0 ; i < join->tables ; i++)
    mark_as_null_row(join->table[i]);		// All fields are NULL
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  DBUG_VOID_RETURN;
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}

/*****************************************************************************
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  Make som simple condition optimization:
  If there is a test 'field = const' change all refs to 'field' to 'const'
  Remove all dummy tests 'item = item', 'const op const'.
  Remove all 'item is NULL', when item can never be null!
  item->marker should be 0 for all items on entry
  Return in cond_value FALSE if condition is impossible (1 = 2)
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*****************************************************************************/

class COND_CMP :public ilink {
public:
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  static void *operator new(size_t size) {return (void*) sql_alloc((uint) size); }
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  static void operator delete(void *ptr __attribute__((unused)),
			      size_t size __attribute__((unused))) {} /*lint -e715 */

  Item *and_level;
  Item_func *cmp_func;
  COND_CMP(Item *a,Item_func *b) :and_level(a),cmp_func(b) {}
};

#ifdef __GNUC__
template class I_List<COND_CMP>;
template class I_List_iterator<COND_CMP>;
template class List<Item_func_match>;
template class List_iterator<Item_func_match>;
#endif

/*
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  change field = field to field = const for each found field = const in the
  and_level
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*/

static void
change_cond_ref_to_const(I_List<COND_CMP> *save_list,Item *and_father,
			 Item *cond, Item *field, Item *value)
{
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  DBUG_ENTER("change_cond_ref_to_const");

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  if (cond->type() == Item::COND_ITEM)
  {
    bool and_level= ((Item_cond*) cond)->functype() ==
      Item_func::COND_AND_FUNC;
    List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
    Item *item;
    while ((item=li++))
      change_cond_ref_to_const(save_list,and_level ? cond : item, item,
			       field, value);
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    DBUG_VOID_RETURN;
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  }
  if (cond->eq_cmp_result() == Item::COND_OK)
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    DBUG_VOID_RETURN;					// Not a boolean function
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  Item_bool_func2 *func=  (Item_bool_func2*) cond;
  Item *left_item=  func->arguments()[0];
  Item *right_item= func->arguments()[1];
  Item_func::Functype functype=  func->functype();

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  if (right_item->eq(field,0) && left_item != value)
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  {
    Item *tmp=value->new_item();
    if (tmp)
    {
      func->arguments()[1] = tmp;
      func->update_used_tables();
      if ((functype == Item_func::EQ_FUNC || functype == Item_func::EQUAL_FUNC)
	  && and_father != cond && !left_item->const_item())
      {
	cond->marker=1;
	COND_CMP *tmp2;
	if ((tmp2=new COND_CMP(and_father,func)))
	  save_list->push_back(tmp2);
      }
      func->set_cmp_func(item_cmp_type(func->arguments()[0]->result_type(),
				       func->arguments()[1]->result_type()));
    }
  }
3139
  else if (left_item->eq(field,0) && right_item != value)
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  {
    Item *tmp=value->new_item();
    if (tmp)
    {
      func->arguments()[0] = value = tmp;
      func->update_used_tables();
      if ((functype == Item_func::EQ_FUNC || functype == Item_func::EQUAL_FUNC)
	  && and_father != cond && !right_item->const_item())
      {
	func->arguments()[0] = func->arguments()[1]; // For easy check
	func->arguments()[1] = value;
	cond->marker=1;
	COND_CMP *tmp2;
	if ((tmp2=new COND_CMP(and_father,func)))
	  save_list->push_back(tmp2);
      }
      func->set_cmp_func(item_cmp_type(func->arguments()[0]->result_type(),
				       func->arguments()[1]->result_type()));
    }
  }
3160
  DBUG_VOID_RETURN;
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}


static void
propagate_cond_constants(I_List<COND_CMP> *save_list,COND *and_level,
			 COND *cond)
{
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  DBUG_ENTER("propagate_cond_constants");

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  if (cond->type() == Item::COND_ITEM)
  {
    bool and_level= ((Item_cond*) cond)->functype() ==
      Item_func::COND_AND_FUNC;
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    List_iterator_fast<Item> li(*((Item_cond*) cond)->argument_list());
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    Item *item;
    I_List<COND_CMP> save;
    while ((item=li++))
    {
      propagate_cond_constants(&save,and_level ? cond : item, item);
    }
    if (and_level)
    {						// Handle other found items
      I_List_iterator<COND_CMP> cond_itr(save);
      COND_CMP *cond_cmp;
      while ((cond_cmp=cond_itr++))
	if (!cond_cmp->cmp_func->arguments()[0]->const_item())
	  change_cond_ref_to_const(&save,cond_cmp->and_level,
				   cond_cmp->and_level,
				   cond_cmp->cmp_func->arguments()[0],
				   cond_cmp->cmp_func->arguments()[1]);
    }
  }
  else if (and_level != cond && !cond->marker)		// In a AND group
  {
    if (cond->type() == Item::FUNC_ITEM &&
	(((Item_func*) cond)->functype() == Item_func::EQ_FUNC ||
	 ((Item_func*) cond)->functype() == Item_func::EQUAL_FUNC))
    {
      Item_func_eq *func=(Item_func_eq*) cond;
      bool left_const= func->arguments()[0]->const_item();
      bool right_const=func->arguments()[1]->const_item();
3202 3203 3204
      if (!(left_const && right_const) &&
	  (func->arguments()[0]->result_type() ==
	   (func->arguments()[1]->result_type())))
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      {
	if (right_const)
	{
	  func->arguments()[1]=resolve_const_item(func->arguments()[1],
						  func->arguments()[0]);
	  func->update_used_tables();
	  change_cond_ref_to_const(save_list,and_level,and_level,
				   func->arguments()[0],
				   func->arguments()[1]);
	}
	else if (left_const)
	{
	  func->arguments()[0]=resolve_const_item(func->arguments()[0],
						  func->arguments()[1]);
	  func->update_used_tables();
	  change_cond_ref_to_const(save_list,and_level,and_level,
				   func->arguments()[1],
				   func->arguments()[0]);
	}
      }
    }
  }
3227
  DBUG_VOID_RETURN;
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}


static COND *
optimize_cond(COND *conds,Item::cond_result *cond_value)
{
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  DBUG_ENTER("optimize_cond");

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  if (!conds)
  {
    *cond_value= Item::COND_TRUE;
3239
    DBUG_RETURN(conds);
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  }
  /* change field = field to field = const for each found field = const */
  DBUG_EXECUTE("where",print_where(conds,"original"););
  propagate_cond_constants((I_List<COND_CMP> *) 0,conds,conds);
  /*
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    Remove all instances of item == item
    Remove all and-levels where CONST item != CONST item
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  */
  DBUG_EXECUTE("where",print_where(conds,"after const change"););
  conds=remove_eq_conds(conds,cond_value) ;
  DBUG_EXECUTE("info",print_where(conds,"after remove"););
3251
  DBUG_RETURN(conds);
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}


/*
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  Remove const and eq items. Return new item, or NULL if no condition
  cond_value is set to according:
  COND_OK    query is possible (field = constant)
  COND_TRUE  always true	( 1 = 1 )
  COND_FALSE always false	( 1 = 2 )
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*/

static COND *
remove_eq_conds(COND *cond,Item::cond_result *cond_value)
{
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  DBUG_ENTER("remove_eq_conds");

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  if (cond->type() == Item::COND_ITEM)
  {
    bool and_level= ((Item_cond*) cond)->functype()
      == Item_func::COND_AND_FUNC;
    List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
    Item::cond_result tmp_cond_value;

    *cond_value=Item::COND_UNDEF;
    Item *item;
    while ((item=li++))
    {
      Item *new_item=remove_eq_conds(item,&tmp_cond_value);
      if (!new_item)
      {
#ifdef DELETE_ITEMS
	delete item;				// This may be shared
#endif
	li.remove();
      }
      else if (item != new_item)
      {
#ifdef DELETE_ITEMS
	delete item;				// This may be shared
#endif
	VOID(li.replace(new_item));
      }
      if (*cond_value == Item::COND_UNDEF)
	*cond_value=tmp_cond_value;
      switch (tmp_cond_value) {
      case Item::COND_OK:			// Not TRUE or FALSE
	if (and_level || *cond_value == Item::COND_FALSE)
	  *cond_value=tmp_cond_value;
	break;
      case Item::COND_FALSE:
	if (and_level)
	{
	  *cond_value=tmp_cond_value;
3305
	  DBUG_RETURN((COND*) 0);			// Always false
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	}
	break;
      case Item::COND_TRUE:
	if (!and_level)
	{
	  *cond_value= tmp_cond_value;
3312
	  DBUG_RETURN((COND*) 0);			// Always true
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	}
	break;
      case Item::COND_UNDEF:			// Impossible
	break; /* purecov: deadcode */
      }
    }
    if (!((Item_cond*) cond)->argument_list()->elements ||
	*cond_value != Item::COND_OK)
3321
      DBUG_RETURN((COND*) 0);
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    if (((Item_cond*) cond)->argument_list()->elements == 1)
    {						// Remove list
      item= ((Item_cond*) cond)->argument_list()->head();
      ((Item_cond*) cond)->argument_list()->empty();
3326
      DBUG_RETURN(item);
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    }
  }
  else if (cond->type() == Item::FUNC_ITEM &&
	   ((Item_func*) cond)->functype() == Item_func::ISNULL_FUNC)
  {
    /*
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      Handles this special case for some ODBC applications:
      The are requesting the row that was just updated with a auto_increment
      value with this construct:

      SELECT * from table_name where auto_increment_column IS NULL
      This will be changed to:
      SELECT * from table_name where auto_increment_column = LAST_INSERT_ID
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    */

    Item_func_isnull *func=(Item_func_isnull*) cond;
    Item **args= func->arguments();
3344
    THD *thd=current_thd;
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    if (args[0]->type() == Item::FIELD_ITEM)
    {
      Field *field=((Item_field*) args[0])->field;
      if (field->flags & AUTO_INCREMENT_FLAG && !field->table->maybe_null &&
3349 3350
	  (thd->options & OPTION_AUTO_IS_NULL) &&
	  thd->insert_id())
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      {
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	query_cache_abort(&thd->net);
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	COND *new_cond;
	if ((new_cond= new Item_func_eq(args[0],
					new Item_int("last_insert_id()",
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						     thd->insert_id(),
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						     21))))
	{
	  cond=new_cond;
3360
	  cond->fix_fields(thd,0);
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	}
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	thd->insert_id(0);		// Clear for next request
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      }
      /* fix to replace 'NULL' dates with '0' (shreeve@uci.edu) */
      else if (((field->type() == FIELD_TYPE_DATE) ||
		(field->type() == FIELD_TYPE_DATETIME)) &&
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		(field->flags & NOT_NULL_FLAG) &&
	       !field->table->maybe_null)
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      {
	COND *new_cond;
	if ((new_cond= new Item_func_eq(args[0],new Item_int("0", 0, 2))))
	{
	  cond=new_cond;
3374
	  cond->fix_fields(thd,0);
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	}
      }
    }
  }
  else if (cond->const_item())
  {
    *cond_value= eval_const_cond(cond) ? Item::COND_TRUE : Item::COND_FALSE;
3382
    DBUG_RETURN((COND*) 0);
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  }
  else if ((*cond_value= cond->eq_cmp_result()) != Item::COND_OK)
  {						// boolan compare function
    Item *left_item=	((Item_func*) cond)->arguments()[0];
    Item *right_item= ((Item_func*) cond)->arguments()[1];
3388
    if (left_item->eq(right_item,1))
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    {
      if (!left_item->maybe_null ||
	  ((Item_func*) cond)->functype() == Item_func::EQUAL_FUNC)
3392
	DBUG_RETURN((COND*) 0);			// Compare of identical items
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    }
  }
  *cond_value=Item::COND_OK;
3396
  DBUG_RETURN(cond);					// Point at next and level
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}

/*
3400
  Return 1 if the item is a const value in all the WHERE clause
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*/

static bool
const_expression_in_where(COND *cond, Item *comp_item, Item **const_item)
{
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  DBUG_ENTER("const_expression_in_where");

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  if (cond->type() == Item::COND_ITEM)
  {
    bool and_level= (((Item_cond*) cond)->functype()
		     == Item_func::COND_AND_FUNC);
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    List_iterator_fast<Item> li(*((Item_cond*) cond)->argument_list());
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    Item *item;
    while ((item=li++))
    {
      bool res=const_expression_in_where(item, comp_item, const_item);
      if (res)					// Is a const value
      {
	if (and_level)
3420
	  DBUG_RETURN(1);
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      }
      else if (!and_level)
3423
	DBUG_RETURN(0);
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    }
3425
    DBUG_RETURN(and_level ? 0 : 1);
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  }
  else if (cond->eq_cmp_result() != Item::COND_OK)
  {						// boolan compare function
    Item_func* func= (Item_func*) cond;
    if (func->functype() != Item_func::EQUAL_FUNC &&
	func->functype() != Item_func::EQ_FUNC)
3432
      DBUG_RETURN(0);
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    Item *left_item=	((Item_func*) cond)->arguments()[0];
    Item *right_item= ((Item_func*) cond)->arguments()[1];
3435
    if (left_item->eq(comp_item,1))
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    {
      if (right_item->const_item())
      {
	if (*const_item)
3440
	  DBUG_RETURN(right_item->eq(*const_item, 1));
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	*const_item=right_item;
3442
	DBUG_RETURN(1);
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      }
    }
3445
    else if (right_item->eq(comp_item,1))
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    {
      if (left_item->const_item())
      {
	if (*const_item)
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	  DBUG_RETURN(left_item->eq(*const_item, 1));
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	*const_item=left_item;
3452
	DBUG_RETURN(1);
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      }
    }
  }
3456
  DBUG_RETURN(0);
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}


/****************************************************************************
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  Create a temp table according to a field list.
  Set distinct if duplicates could be removed
  Given fields field pointers are changed to point at tmp_table
  for send_fields
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****************************************************************************/

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Field *create_tmp_field(THD *thd, TABLE *table,Item *item, Item::Type type,
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			Item_result_field ***copy_func, Field **from_field,
			bool group, bool modify_item)
{
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  DBUG_ENTER("*create_tmp_field");

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  switch (type) {
  case Item::SUM_FUNC_ITEM:
  {
    Item_sum *item_sum=(Item_sum*) item;
    bool maybe_null=item_sum->maybe_null;
    switch (item_sum->sum_func()) {
    case Item_sum::AVG_FUNC:			/* Place for sum & count */
      if (group)
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      {
	DBUG_RETURN(new Field_string(sizeof(double)+sizeof(longlong),
				maybe_null, item->name,table,1));
      }
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      else
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      {
	DBUG_RETURN(new Field_double(item_sum->max_length,maybe_null,
				item->name, table, item_sum->decimals));
      }
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    case Item_sum::STD_FUNC:			/* Place for sum & count */
      if (group)
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      {
	DBUG_RETURN(new Field_string(sizeof(double)*2+sizeof(longlong),
				 maybe_null, item->name,table,1));
      }
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      else
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      {
	DBUG_RETURN(new Field_double(item_sum->max_length, maybe_null,
				item->name,table,item_sum->decimals));
      }
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    case Item_sum::UNIQUE_USERS_FUNC:
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      DBUG_RETURN(new Field_long(9,maybe_null,item->name,table,1));
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    default:
      switch (item_sum->result_type()) {
      case REAL_RESULT:
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	DBUG_RETURN(new Field_double(item_sum->max_length,maybe_null,
				item->name,table,item_sum->decimals));
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      case INT_RESULT:
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	DBUG_RETURN(new Field_longlong(item_sum->max_length,maybe_null,
				  item->name,table,item->unsigned_flag));
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      case STRING_RESULT:
	if (item_sum->max_length > 255)
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	  DBUG_RETURN(new Field_blob(item_sum->max_length,maybe_null,
				 item->name,table,item->binary));
	DBUG_RETURN(new Field_string(item_sum->max_length,maybe_null,
				 item->name,table,item->binary));
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      }
    }
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    thd->fatal_error=1;
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    DBUG_RETURN(0);					// Error
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  }
  case Item::FIELD_ITEM:
  {
    Field *org_field=((Item_field*) item)->field,*new_field;

    *from_field=org_field;
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    // The following should always be true
    if ((new_field= org_field->new_field(&thd->mem_root,table)))
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    {
      if (modify_item)
	((Item_field*) item)->result_field= new_field;
      else
	new_field->field_name=item->name;
      if (org_field->maybe_null())
	new_field->flags&= ~NOT_NULL_FLAG;	// Because of outer join
    }
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    DBUG_RETURN(new_field);
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  }
  case Item::PROC_ITEM:
  case Item::FUNC_ITEM:
  case Item::COND_ITEM:
  case Item::FIELD_AVG_ITEM:
  case Item::FIELD_STD_ITEM:
    /* The following can only happen with 'CREATE TABLE ... SELECT' */
  case Item::INT_ITEM:
  case Item::REAL_ITEM:
  case Item::STRING_ITEM:
  case Item::REF_ITEM:
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  case Item::NULL_ITEM:
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  {
    bool maybe_null=item->maybe_null;
    Field *new_field;
    LINT_INIT(new_field);

    switch (item->result_type()) {
    case REAL_RESULT:
      new_field=new Field_double(item->max_length,maybe_null,
				 item->name,table,item->decimals);
      break;
    case INT_RESULT:
      new_field=new Field_longlong(item->max_length,maybe_null,
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				   item->name,table, item->unsigned_flag);
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      break;
    case STRING_RESULT:
      if (item->max_length > 255)
	new_field=  new Field_blob(item->max_length,maybe_null,
				   item->name,table,item->binary);
      else
	new_field= new Field_string(item->max_length,maybe_null,
				    item->name,table,item->binary);
      break;
    }
    if (copy_func)
      *((*copy_func)++) = (Item_result_field*) item; // Save for copy_funcs
    if (modify_item)
      ((Item_result_field*) item)->result_field=new_field;
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    DBUG_RETURN(new_field);
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  }
  default:					// Dosen't have to be stored
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    DBUG_RETURN(0);
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  }
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  DBUG_RETURN(0); // impossible
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}


TABLE *
create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
		 ORDER *group, bool distinct, bool save_sum_fields,
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		 bool allow_distinct_limit, ulong select_options)
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{
  TABLE *table;
  uint	i,field_count,reclength,null_count,null_pack_length,
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        hidden_null_count, hidden_null_pack_length, hidden_field_count,
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	blob_count,group_null_items;
  bool	using_unique_constraint=0;
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  bool  not_all_columns= !(select_options & TMP_TABLE_ALL_COLUMNS);
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  char	*tmpname,path[FN_REFLEN];
  byte	*pos,*group_buff;
  uchar *null_flags;
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  Field **reg_field, **from_field, **blob_field;
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  Copy_field *copy=0;
  KEY *keyinfo;
  KEY_PART_INFO *key_part_info;
  Item_result_field **copy_func;
  MI_COLUMNDEF *recinfo;
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  uint temp_pool_slot=MY_BIT_NONE;
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  DBUG_ENTER("create_tmp_table");
3608

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  DBUG_PRINT("enter",("distinct: %d  save_sum_fields: %d  allow_distinct_limit: %d  group: %d",
		      (int) distinct, (int) save_sum_fields,
		      (int) allow_distinct_limit,test(group)));

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  statistic_increment(created_tmp_tables, &LOCK_status);
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  if (use_temp_pool)
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    temp_pool_slot = bitmap_set_next(&temp_pool);
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  if (temp_pool_slot != MY_BIT_NONE) // we got a slot
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    sprintf(path, "%s%s_%lx_%i", mysql_tmpdir, tmp_file_prefix,
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	    current_pid, temp_pool_slot);
  else // if we run out of slots or we are not using tempool
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    sprintf(path,"%s%s%lx_%lx_%x",mysql_tmpdir,tmp_file_prefix,current_pid,
            thd->thread_id, thd->tmp_table++);

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  if (group)
  {
    if (!param->quick_group)
      group=0;					// Can't use group key
    else for (ORDER *tmp=group ; tmp ; tmp=tmp->next)
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    {
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      (*tmp->item)->marker=4;			// Store null in key
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      if ((*tmp->item)->max_length >= MAX_CHAR_WIDTH)
	using_unique_constraint=1;
    }
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    if (param->group_length >= MAX_BLOB_WIDTH)
      using_unique_constraint=1;
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    if (group)
      distinct=0;				// Can't use distinct
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  }

  field_count=param->field_count+param->func_count+param->sum_func_count;
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  hidden_field_count=param->hidden_field_count;
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  if (!my_multi_malloc(MYF(MY_WME),
		       &table,sizeof(*table),
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		       &reg_field,  sizeof(Field*)*(field_count+1),
		       &blob_field, sizeof(Field*)*(field_count+1),
		       &from_field, sizeof(Field*)*field_count,
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		       &copy_func,sizeof(*copy_func)*(param->func_count+1),
		       &param->keyinfo,sizeof(*param->keyinfo),
		       &key_part_info,
		       sizeof(*key_part_info)*(param->group_parts+1),
		       &param->start_recinfo,
		       sizeof(*param->recinfo)*(field_count*2+4),
		       &tmpname,(uint) strlen(path)+1,
		       &group_buff,group && ! using_unique_constraint ?
		       param->group_length : 0,
		       NullS))
  {
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    bitmap_clear_bit(&temp_pool, temp_pool_slot);
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    DBUG_RETURN(NULL); /* purecov: inspected */
  }
  if (!(param->copy_field=copy=new Copy_field[field_count]))
  {
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    bitmap_clear_bit(&temp_pool, temp_pool_slot);
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    my_free((gptr) table,MYF(0)); /* purecov: inspected */
    DBUG_RETURN(NULL); /* purecov: inspected */
  }
  param->funcs=copy_func;
  strmov(tmpname,path);
  /* make table according to fields */

  bzero((char*) table,sizeof(*table));
  bzero((char*) reg_field,sizeof(Field*)*(field_count+1));
  bzero((char*) from_field,sizeof(Field*)*field_count);
  table->field=reg_field;
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  table->blob_field= (Field_blob**) blob_field;
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  table->real_name=table->path=tmpname;
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  /*
    This must be "" as field may refer to it after tempory table is dropped
  */
  table->table_name= (char*) "";
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  table->reginfo.lock_type=TL_WRITE;	/* Will be updated */
  table->db_stat=HA_OPEN_KEYFILE+HA_OPEN_RNDFILE;
  table->blob_ptr_size=mi_portable_sizeof_char_ptr;
  table->map=1;
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  table->tmp_table= TMP_TABLE;
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  table->db_low_byte_first=1;			// True for HEAP and MyISAM
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  table->temp_pool_slot = temp_pool_slot;
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  table->copy_blobs= 1;
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  /* Calculate which type of fields we will store in the temporary table */
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  reclength=blob_count=null_count=hidden_null_count=group_null_items=0;
  param->using_indirect_summary_function=0;
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  List_iterator_fast<Item> li(fields);
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  Item *item;
  Field **tmp_from_field=from_field;
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  while ((item=li++))
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  {
    Item::Type type=item->type();
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    if (not_all_columns)
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    {
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      if (item->with_sum_func && type != Item::SUM_FUNC_ITEM)
      {
	/*
	  Mark that the we have ignored an item that refers to a summary
	  function. We need to know this if someone is going to use
	  DISTINCT on the result.
	*/
	param->using_indirect_summary_function=1;
	continue;
      }
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      if (item->const_item() && (int) hidden_field_count <= 0)
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        continue; // We don't have to store this
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    }
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    if (type == Item::SUM_FUNC_ITEM && !group && !save_sum_fields)
    {						/* Can't calc group yet */
      ((Item_sum*) item)->result_field=0;
      for (i=0 ; i < ((Item_sum*) item)->arg_count ; i++)
      {
	Item *arg= ((Item_sum*) item)->args[i];
	if (!arg->const_item())
	{
	  Field *new_field=
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	    create_tmp_field(thd, table,arg,arg->type(),&copy_func,
			     tmp_from_field, group != 0,not_all_columns);
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	  if (!new_field)
	    goto err;					// Should be OOM
	  tmp_from_field++;
	  *(reg_field++)= new_field;
	  reclength+=new_field->pack_length();
	  if (!(new_field->flags & NOT_NULL_FLAG))
	    null_count++;
	  if (new_field->flags & BLOB_FLAG)
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	  {
	    *blob_field++= new_field;
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	    blob_count++;
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	  }
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	  ((Item_sum*) item)->args[i]= new Item_field(new_field);
	}
      }
    }
    else
    {
3746
      Field *new_field=create_tmp_field(thd, table, item,type, &copy_func,
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					tmp_from_field, group != 0,
					not_all_columns);
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      if (!new_field)
      {
	if (thd->fatal_error)
	  goto err;				// Got OOM
	continue;				// Some kindf of const item
      }
      if (type == Item::SUM_FUNC_ITEM)
	((Item_sum *) item)->result_field= new_field;
      tmp_from_field++;
      reclength+=new_field->pack_length();
      if (!(new_field->flags & NOT_NULL_FLAG))
	null_count++;
      if (new_field->flags & BLOB_FLAG)
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      {
	*blob_field++= new_field;
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	blob_count++;
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      }
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      if (item->marker == 4 && item->maybe_null)
      {
	group_null_items++;
	new_field->flags|= GROUP_FLAG;
      }
      *(reg_field++) =new_field;
    }
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    if (!--hidden_field_count)
      hidden_null_count=null_count;
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  }
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  DBUG_ASSERT(field_count >= (uint) (reg_field - table->field));
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  field_count= (uint) (reg_field - table->field);
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  *blob_field= 0;				// End marker
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  /* If result table is small; use a heap */
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  if (blob_count || using_unique_constraint ||
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      (select_options & (OPTION_BIG_TABLES | SELECT_SMALL_RESULT)) ==
      OPTION_BIG_TABLES)
  {
    table->file=get_new_handler(table,table->db_type=DB_TYPE_MYISAM);
    if (group &&
	(param->group_parts > table->file->max_key_parts() ||
	 param->group_length > table->file->max_key_length()))
      using_unique_constraint=1;
  }
  else
  {
    table->file=get_new_handler(table,table->db_type=DB_TYPE_HEAP);
  }

  if (!using_unique_constraint)
    reclength+= group_null_items;	// null flag is stored separately

  table->blob_fields=blob_count;
  if (blob_count == 0)
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  {
    /* We need to ensure that first byte is not 0 for the delete link */
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    if (param->hidden_field_count)
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      hidden_null_count++;
    else
      null_count++;
  }
  hidden_null_pack_length=(hidden_null_count+7)/8;
  null_pack_length=hidden_null_count+(null_count+7)/8;
  reclength+=null_pack_length;
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  if (!reclength)
    reclength=1;				// Dummy select

  table->fields=field_count;
  table->reclength=reclength;
  {
    uint alloc_length=ALIGN_SIZE(reclength+MI_UNIQUE_HASH_LENGTH+1);
    table->rec_buff_length=alloc_length;
    if (!(table->record[0]= (byte *) my_malloc(alloc_length*3, MYF(MY_WME))))
      goto err;
    table->record[1]= table->record[0]+alloc_length;
    table->record[2]= table->record[1]+alloc_length;
  }
  copy_func[0]=0;				// End marker

  recinfo=param->start_recinfo;
  null_flags=(uchar*) table->record[0];
  pos=table->record[0]+ null_pack_length;
  if (null_pack_length)
  {
    bzero((byte*) recinfo,sizeof(*recinfo));
    recinfo->type=FIELD_NORMAL;
    recinfo->length=null_pack_length;
    recinfo++;
    bfill(null_flags,null_pack_length,255);	// Set null fields
  }
  null_count= (blob_count == 0) ? 1 : 0;
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  hidden_field_count=param->hidden_field_count;
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  for (i=0,reg_field=table->field; i < field_count; i++,reg_field++,recinfo++)
  {
    Field *field= *reg_field;
    uint length;
    bzero((byte*) recinfo,sizeof(*recinfo));

    if (!(field->flags & NOT_NULL_FLAG))
    {
      if (field->flags & GROUP_FLAG && !using_unique_constraint)
      {
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	/*
	  We have to reserve one byte here for NULL bits,
	  as this is updated by 'end_update()'
	*/
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	*pos++=0;				// Null is stored here
	recinfo->length=1;
	recinfo->type=FIELD_NORMAL;
	recinfo++;
	bzero((byte*) recinfo,sizeof(*recinfo));
      }
      else
      {
	recinfo->null_bit= 1 << (null_count & 7);
	recinfo->null_pos= null_count/8;
      }
      field->move_field((char*) pos,null_flags+null_count/8,
			1 << (null_count & 7));
      null_count++;
    }
    else
      field->move_field((char*) pos,(uchar*) 0,0);
    field->reset();
    if (from_field[i])
    {						/* Not a table Item */
      copy->set(field,from_field[i],save_sum_fields);
      copy++;
    }
    length=field->pack_length();
    pos+= length;

    /* Make entry for create table */
    recinfo->length=length;
    if (field->flags & BLOB_FLAG)
      recinfo->type= (int) FIELD_BLOB;
    else if (!field->zero_pack() &&
	     (field->type() == FIELD_TYPE_STRING ||
	      field->type() == FIELD_TYPE_VAR_STRING) &&
	     length >= 10 && blob_count)
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      recinfo->type=FIELD_SKIP_ENDSPACE;
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    else
      recinfo->type=FIELD_NORMAL;
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    if (!--hidden_field_count)
      null_count=(null_count+7) & ~7;		// move to next byte
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  }

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  param->copy_field_end=copy;
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  param->recinfo=recinfo;
  store_record(table,2);			// Make empty default record

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  if (thd->variables.tmp_table_size == ~(ulong) 0)		// No limit
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    table->max_rows= ~(ha_rows) 0;
  else
    table->max_rows=(((table->db_type == DB_TYPE_HEAP) ?
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		      min(thd->variables.tmp_table_size,
			  thd->variables.max_heap_table_size) :
		      thd->variables.tmp_table_size)/ table->reclength);
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  set_if_bigger(table->max_rows,1);		// For dummy start options
  keyinfo=param->keyinfo;

  if (group)
  {
    DBUG_PRINT("info",("Creating group key in temporary table"));
    table->group=group;				/* Table is grouped by key */
    param->group_buff=group_buff;
    table->keys=1;
    table->uniques= test(using_unique_constraint);
    table->key_info=keyinfo;
    keyinfo->key_part=key_part_info;
    keyinfo->flags=HA_NOSAME;
    keyinfo->usable_key_parts=keyinfo->key_parts= param->group_parts;
    keyinfo->key_length=0;
    keyinfo->rec_per_key=0;
    for (; group ; group=group->next,key_part_info++)
    {
      Field *field=(*group->item)->tmp_table_field();
      bool maybe_null=(*group->item)->maybe_null;
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      key_part_info->null_bit=0;
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      key_part_info->field=  field;
      key_part_info->offset= field->offset();
      key_part_info->length= (uint16) field->pack_length();
      key_part_info->type=   (uint8) field->key_type();
      key_part_info->key_type =
	((ha_base_keytype) key_part_info->type == HA_KEYTYPE_TEXT ||
	 (ha_base_keytype) key_part_info->type == HA_KEYTYPE_VARTEXT) ?
	0 : FIELDFLAG_BINARY;
      if (!using_unique_constraint)
      {
	group->buff=(char*) group_buff;
3937
	if (!(group->field=field->new_field(&thd->mem_root,table)))
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	  goto err; /* purecov: inspected */
	if (maybe_null)
	{
	  /*
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	    To be able to group on NULL, we reserve place in group_buff
	    for the NULL flag just before the column.
	    The field data is after this flag.
	    The NULL flag is updated by 'end_update()' and 'end_write()'
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	  */
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	  keyinfo->flags|= HA_NULL_ARE_EQUAL;	// def. that NULL == NULL
	  key_part_info->null_bit=field->null_bit;
	  key_part_info->null_offset= (uint) (field->null_ptr -
					      (uchar*) table->record[0]);
	  group->field->move_field((char*) ++group->buff);
3952
	  group_buff++;
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	}
	else
	  group->field->move_field((char*) group_buff);
	group_buff+= key_part_info->length;
      }
      keyinfo->key_length+=  key_part_info->length;
    }
  }

3962
  if (distinct)
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  {
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    /*
      Create an unique key or an unique constraint over all columns
      that should be in the result.  In the temporary table, there are
      'param->hidden_field_count' extra columns, whose null bits are stored
      in the first 'hidden_null_pack_length' bytes of the row.
    */
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    DBUG_PRINT("info",("hidden_field_count: %d", param->hidden_field_count));

3972
    null_pack_length-=hidden_null_pack_length;
3973
    keyinfo->key_parts= ((field_count-param->hidden_field_count)+
3974
			 test(null_pack_length));
3975
    if (allow_distinct_limit)
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    {
      set_if_smaller(table->max_rows,thd->select_limit);
      param->end_write_records=thd->select_limit;
    }
    else
      param->end_write_records= HA_POS_ERROR;
    table->distinct=1;
    table->keys=1;
    if (blob_count)
    {
      using_unique_constraint=1;
      table->uniques=1;
    }
    if (!(key_part_info= (KEY_PART_INFO*)
	  sql_calloc((keyinfo->key_parts)*sizeof(KEY_PART_INFO))))
      goto err;
    table->key_info=keyinfo;
    keyinfo->key_part=key_part_info;
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    keyinfo->flags=HA_NOSAME | HA_NULL_ARE_EQUAL;
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    keyinfo->key_length=(uint16) reclength;
    keyinfo->name=(char*) "tmp";
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    if (null_pack_length)
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    {
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      key_part_info->null_bit=0;
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      key_part_info->offset=hidden_null_pack_length;
      key_part_info->length=null_pack_length;
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      key_part_info->field=new Field_string((char*) table->record[0],
					    (uint32) key_part_info->length,
					    (uchar*) 0,
					    (uint) 0,
					    Field::NONE,
					    NullS, table, (bool) 1);
      key_part_info->key_type=FIELDFLAG_BINARY;
      key_part_info->type=    HA_KEYTYPE_BINARY;
      key_part_info++;
    }
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    /* Create a distinct key over the columns we are going to return */
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    for (i=param->hidden_field_count, reg_field=table->field + i ;
	 i < field_count;
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	 i++, reg_field++, key_part_info++)
    {
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      key_part_info->null_bit=0;
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      key_part_info->field=    *reg_field;
      key_part_info->offset=   (*reg_field)->offset();
      key_part_info->length=   (uint16) (*reg_field)->pack_length();
      key_part_info->type=     (uint8) (*reg_field)->key_type();
      key_part_info->key_type =
	((ha_base_keytype) key_part_info->type == HA_KEYTYPE_TEXT ||
	 (ha_base_keytype) key_part_info->type == HA_KEYTYPE_VARTEXT) ?
	0 : FIELDFLAG_BINARY;
    }
  }
  if (thd->fatal_error)				// If end of memory
    goto err;					 /* purecov: inspected */
  table->db_record_offset=1;
  if (table->db_type == DB_TYPE_MYISAM)
  {
    if (create_myisam_tmp_table(table,param,select_options))
      goto err;
  }
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  /* Set table_name for easier debugging */
  table->table_name= base_name(tmpname);
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  if (!open_tmp_table(table))
    DBUG_RETURN(table);

 err:
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  /*
    Hack to ensure that free_blobs() doesn't fail if blob_field is not yet
    complete
  */
  *table->blob_field= 0;
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  free_tmp_table(thd,table);                    /* purecov: inspected */
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  bitmap_clear_bit(&temp_pool, temp_pool_slot);
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  DBUG_RETURN(NULL);				/* purecov: inspected */
}


static bool open_tmp_table(TABLE *table)
{
  int error;
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  DBUG_ENTER("open_tmp_table");

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  if ((error=table->file->ha_open(table->real_name,O_RDWR,HA_OPEN_TMP_TABLE)))
  {
    table->file->print_error(error,MYF(0)); /* purecov: inspected */
    table->db_stat=0;
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    DBUG_RETURN((1));
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  }
  /* VOID(ha_lock(table,F_WRLCK)); */		/* Single thread table */
  (void) table->file->extra(HA_EXTRA_QUICK);		/* Faster */
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  DBUG_RETURN((0));
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}


static bool create_myisam_tmp_table(TABLE *table,TMP_TABLE_PARAM *param,
4071
				    ulong options)
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{
  int error;
  MI_KEYDEF keydef;
  MI_UNIQUEDEF uniquedef;
  KEY *keyinfo=param->keyinfo;
  DBUG_ENTER("create_myisam_tmp_table");
4078

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  if (table->keys)
  {						// Get keys for ni_create
    bool using_unique_constraint=0;
    MI_KEYSEG *seg= (MI_KEYSEG*) sql_calloc(sizeof(*seg) *
					    keyinfo->key_parts);
    if (!seg)
      goto err;

    if (keyinfo->key_length >= table->file->max_key_length() ||
	keyinfo->key_parts > table->file->max_key_parts() ||
	table->uniques)
    {
      /* Can't create a key; Make a unique constraint instead of a key */
      table->keys=0;
      table->uniques=1;
      using_unique_constraint=1;
      bzero((char*) &uniquedef,sizeof(uniquedef));
      uniquedef.keysegs=keyinfo->key_parts;
      uniquedef.seg=seg;
      uniquedef.null_are_equal=1;

      /* Create extra column for hash value */
      bzero((byte*) param->recinfo,sizeof(*param->recinfo));
      param->recinfo->type= FIELD_CHECK;
      param->recinfo->length=MI_UNIQUE_HASH_LENGTH;
      param->recinfo++;
      table->reclength+=MI_UNIQUE_HASH_LENGTH;
    }
    else
    {
      /* Create an unique key */
      bzero((char*) &keydef,sizeof(keydef));
      keydef.flag=HA_NOSAME | HA_BINARY_PACK_KEY | HA_PACK_KEY;
      keydef.keysegs=  keyinfo->key_parts;
      keydef.seg= seg;
    }
    for (uint i=0; i < keyinfo->key_parts ; i++,seg++)
    {
      Field *field=keyinfo->key_part[i].field;
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      seg->flag=     0;
      seg->language= MY_CHARSET_CURRENT;
      seg->length=   keyinfo->key_part[i].length;
      seg->start=    keyinfo->key_part[i].offset;
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      if (field->flags & BLOB_FLAG)
      {
	seg->type=
	((keyinfo->key_part[i].key_type & FIELDFLAG_BINARY) ?
	 HA_KEYTYPE_VARBINARY : HA_KEYTYPE_VARTEXT);
	seg->bit_start=seg->length - table->blob_ptr_size;
	seg->flag= HA_BLOB_PART;
	seg->length=0;			// Whole blob in unique constraint
      }
      else
      {
	seg->type=
	  ((keyinfo->key_part[i].key_type & FIELDFLAG_BINARY) ?
	   HA_KEYTYPE_BINARY : HA_KEYTYPE_TEXT);
	if (!(field->flags & ZEROFILL_FLAG) &&
	    (field->type() == FIELD_TYPE_STRING ||
	     field->type() == FIELD_TYPE_VAR_STRING) &&
	    keyinfo->key_part[i].length > 4)
	  seg->flag|=HA_SPACE_PACK;
      }
4142
      if (!(field->flags & NOT_NULL_FLAG))
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      {
	seg->null_bit= field->null_bit;
	seg->null_pos= (uint) (field->null_ptr - (uchar*) table->record[0]);
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	/*
	  We are using a GROUP BY on something that contains NULL
	  In this case we have to tell MyISAM that two NULL should
	  on INSERT be compared as equal
	*/
	if (!using_unique_constraint)
	  keydef.flag|= HA_NULL_ARE_EQUAL;
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      }
    }
  }
  MI_CREATE_INFO create_info;
  bzero((char*) &create_info,sizeof(create_info));
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  if ((options & (OPTION_BIG_TABLES | SELECT_SMALL_RESULT)) ==
      OPTION_BIG_TABLES)
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    create_info.data_file_length= ~(ulonglong) 0;

  if ((error=mi_create(table->real_name,table->keys,&keydef,
		       (uint) (param->recinfo-param->start_recinfo),
		       param->start_recinfo,
		       table->uniques, &uniquedef,
		       &create_info,
		       HA_CREATE_TMP_TABLE)))
  {
    table->file->print_error(error,MYF(0));	/* purecov: inspected */
    table->db_stat=0;
    goto err;
  }
4173
  statistic_increment(created_tmp_disk_tables, &LOCK_status);
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  table->db_record_offset=1;
  DBUG_RETURN(0);
 err:
  DBUG_RETURN(1);
}


void
free_tmp_table(THD *thd, TABLE *entry)
{
  const char *save_proc_info;
  DBUG_ENTER("free_tmp_table");
  DBUG_PRINT("enter",("table: %s",entry->table_name));

  save_proc_info=thd->proc_info;
  thd->proc_info="removing tmp table";
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  free_blobs(entry);
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  if (entry->db_stat && entry->file)
  {
    (void) entry->file->close();
    delete entry->file;
  }
  if (!(test_flags & TEST_KEEP_TMP_TABLES) || entry->db_type == DB_TYPE_HEAP)
    (void) ha_delete_table(entry->db_type,entry->real_name);
  /* free blobs */
  for (Field **ptr=entry->field ; *ptr ; ptr++)
    delete *ptr;
  my_free((gptr) entry->record[0],MYF(0));
  free_io_cache(entry);
4203

4204
  bitmap_clear_bit(&temp_pool, entry->temp_pool_slot);
4205

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  my_free((gptr) entry,MYF(0));
  thd->proc_info=save_proc_info;

  DBUG_VOID_RETURN;
}

/*
* If a HEAP table gets full, create a MyISAM table and copy all rows to this
*/

bool create_myisam_from_heap(TABLE *table, TMP_TABLE_PARAM *param, int error,
			     bool ignore_last_dupp_key_error)
{
  TABLE new_table;
  const char *save_proc_info;
  THD *thd=current_thd;
  int write_err;
  DBUG_ENTER("create_myisam_from_heap");

  if (table->db_type != DB_TYPE_HEAP || error != HA_ERR_RECORD_FILE_FULL)
  {
    table->file->print_error(error,MYF(0));
    DBUG_RETURN(1);
  }
  new_table= *table;
  new_table.db_type=DB_TYPE_MYISAM;
  if (!(new_table.file=get_new_handler(&new_table,DB_TYPE_MYISAM)))
    DBUG_RETURN(1);				// End of memory

  save_proc_info=thd->proc_info;
  thd->proc_info="converting HEAP to MyISAM";

  if (create_myisam_tmp_table(&new_table,param,
4239
			      thd->lex.select_lex.options | thd->options))
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    goto err2;
  if (open_tmp_table(&new_table))
    goto err1;
  table->file->index_end();
  table->file->rnd_init();
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  if (table->no_rows)
  {
4247 4248
    new_table.file->extra(HA_EXTRA_NO_ROWS);
    new_table.no_rows=1;
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  }

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  /* copy all old rows */
  while (!table->file->rnd_next(new_table.record[1]))
  {
    if ((write_err=new_table.file->write_row(new_table.record[1])))
      goto err;
  }
  /* copy row that filled HEAP table */
  if ((write_err=new_table.file->write_row(table->record[0])))
  {
    if (write_err != HA_ERR_FOUND_DUPP_KEY &&
	write_err != HA_ERR_FOUND_DUPP_UNIQUE || !ignore_last_dupp_key_error)
    goto err;
  }

  /* remove heap table and change to use myisam table */
  (void) table->file->rnd_end();
  (void) table->file->close();
  (void) table->file->delete_table(table->real_name);
  delete table->file;
  table->file=0;
  *table =new_table;
  table->file->change_table_ptr(table);
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  thd->proc_info= (!strcmp(save_proc_info,"Copying to tmp table") ?
		   "Copying to tmp table on disk" : save_proc_info);
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  DBUG_RETURN(0);

 err:
  DBUG_PRINT("error",("Got error: %d",write_err));
  table->file->print_error(error,MYF(0));	// Give table is full error
  (void) table->file->rnd_end();
  (void) new_table.file->close();
 err1:
  new_table.file->delete_table(new_table.real_name);
  delete new_table.file;
 err2:
  thd->proc_info=save_proc_info;
  DBUG_RETURN(1);
}


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/****************************************************************************
  Make a join of all tables and write it on socket or to table
  Return:  0 if ok
           1 if error is sent
          -1 if error should be sent
****************************************************************************/
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static int
do_select(JOIN *join,List<Item> *fields,TABLE *table,Procedure *procedure)
{
  int error;
  JOIN_TAB *join_tab;
  int (*end_select)(JOIN *, struct st_join_table *,bool);
  DBUG_ENTER("do_select");

  join->procedure=procedure;
  /*
4308
    Tell the client how many fields there are in a row
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  */
  if (!table)
    join->result->send_fields(*fields,1);
  else
  {
    VOID(table->file->extra(HA_EXTRA_WRITE_CACHE));
    empty_record(table);
  }
  join->tmp_table=table;			/* Save for easy recursion */
  join->fields= fields;

  /* Set up select_end */
  if (table)
  {
    if (table->group && join->tmp_table_param.sum_func_count)
    {
      if (table->keys)
      {
4327
	DBUG_PRINT("info",("Using end_update"));
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	end_select=end_update;
	table->file->index_init(0);
      }
      else
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      {
	DBUG_PRINT("info",("Using end_unique_update"));
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	end_select=end_unique_update;
4335
      }
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    }
    else if (join->sort_and_group)
    {
      DBUG_PRINT("info",("Using end_write_group"));
      end_select=end_write_group;
    }
    else
    {
      DBUG_PRINT("info",("Using end_write"));
      end_select=end_write;
    }
  }
  else
  {
    if (join->sort_and_group || (join->procedure &&
				 join->procedure->flags & PROC_GROUP))
      end_select=end_send_group;
    else
      end_select=end_send;
  }
  join->join_tab[join->tables-1].next_select=end_select;

  join_tab=join->join_tab+join->const_tables;
  join->send_records=0;
  if (join->tables == join->const_tables)
  {
    if (!(error=(*end_select)(join,join_tab,0)) || error == -3)
      error=(*end_select)(join,join_tab,1);
  }
  else
  {
    error=sub_select(join,join_tab,0);
    if (error >= 0)
      error=sub_select(join,join_tab,1);
    if (error == -3)
      error=0;					/* select_limit used */
  }
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  /* Return 1 if error is sent;  -1 if error should be sent */
4375
  if (error < 0)
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  {
    join->result->send_error(0,NullS);		/* purecov: inspected */
    error=1;					// Error sent
  }
4380
  else
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  {
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    error=0;
    if (!table)					// If sending data to client
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    {
      join_free(join);				// Unlock all cursors
      if (join->result->send_eof())
4387
	error= 1;				// Don't send error
4388
    }
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    DBUG_PRINT("info",("%ld records output",join->send_records));
  }
  if (table)
  {
4393
    int tmp;
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    if ((tmp=table->file->extra(HA_EXTRA_NO_CACHE)))
    {
      my_errno=tmp;
      error= -1;
    }
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    if ((tmp=table->file->index_end()))
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    {
      my_errno=tmp;
      error= -1;
    }
4404
    if (error == -1)
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      table->file->print_error(my_errno,MYF(0));
  }
4407
  DBUG_RETURN(error);
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}


static int
sub_select_cache(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
{
  int error;
4415
  DBUG_ENTER("sub_select_cache");
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  if (end_of_records)
  {
    if ((error=flush_cached_records(join,join_tab,FALSE)) < 0)
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      DBUG_RETURN(error); /* purecov: inspected */
    DBUG_RETURN(sub_select(join,join_tab,end_of_records));
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  }
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  if (join->thd->killed)		// If aborted by user
  {
    my_error(ER_SERVER_SHUTDOWN,MYF(0)); /* purecov: inspected */
4426
    DBUG_RETURN(-2);				 /* purecov: inspected */
4427
  }
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  if (join_tab->use_quick != 2 || test_if_quick_select(join_tab) <= 0)
  {
    if (!store_record_in_cache(&join_tab->cache))
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      DBUG_RETURN(0);					// There is more room in cache
    DBUG_RETURN(flush_cached_records(join,join_tab,FALSE));
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  }
  if ((error=flush_cached_records(join,join_tab,TRUE)) < 0)
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    DBUG_RETURN(error); /* purecov: inspected */
  DBUG_RETURN(sub_select(join,join_tab,end_of_records)); /* Use ordinary select */
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}


static int
sub_select(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
{
4443
  DBUG_ENTER("sub_select");
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  join_tab->table->null_row=0;
  if (end_of_records)
4447
    DBUG_RETURN((*join_tab->next_select)(join,join_tab+1,end_of_records));
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  /* Cache variables for faster loop */
  int error;
  bool found=0;
  COND *on_expr=join_tab->on_expr, *select_cond=join_tab->select_cond;

  if (!(error=(*join_tab->read_first_record)(join_tab)))
  {
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    bool not_exists_optimize= join_tab->table->reginfo.not_exists_optimize;
    bool not_used_in_distinct=join_tab->not_used_in_distinct;
    ha_rows found_records=join->found_records;
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    READ_RECORD *info= &join_tab->read_record;

    do
    {
      if (join->thd->killed)			// Aborted by user
      {
	my_error(ER_SERVER_SHUTDOWN,MYF(0));	/* purecov: inspected */
4466
	DBUG_RETURN(-2);				/* purecov: inspected */
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      }
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      join->examined_rows++;
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      if (!on_expr || on_expr->val_int())
      {
	found=1;
	if (not_exists_optimize)
	  break;			// Searching after not null columns
	if (!select_cond || select_cond->val_int())
	{
4476
	  if ((error=(*join_tab->next_select)(join,join_tab+1,0)) < 0)
4477
	    DBUG_RETURN(error);
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	  if (not_used_in_distinct && found_records != join->found_records)
4479
	    DBUG_RETURN(0);
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	}
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	else
	  info->file->unlock_row();
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      }
    } while (!(error=info->read_record(info)));
  }
4486
  if (error > 0)				// Fatal error
4487
    DBUG_RETURN(-1);
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  if (!found && on_expr)
  {						// OUTER JOIN
    restore_record(join_tab->table,2);		// Make empty record
    mark_as_null_row(join_tab->table);		// For group by without error
    if (!select_cond || select_cond->val_int())
    {
4495
      if ((error=(*join_tab->next_select)(join,join_tab+1,0)) < 0)
4496
	DBUG_RETURN(error);				/* purecov: inspected */
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    }
  }
4499
  DBUG_RETURN(0);
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}


static int
flush_cached_records(JOIN *join,JOIN_TAB *join_tab,bool skipp_last)
{
  int error;
  READ_RECORD *info;
4508
  DBUG_ENTER("flush_cached_records");
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  if (!join_tab->cache.records)
4511
    DBUG_RETURN(0);				/* Nothing to do */
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  if (skipp_last)
    (void) store_record_in_cache(&join_tab->cache); // Must save this for later
  if (join_tab->use_quick == 2)
  {
    if (join_tab->select->quick)
    {					/* Used quick select last. reset it */
      delete join_tab->select->quick;
      join_tab->select->quick=0;
    }
  }
 /* read through all records */
  if ((error=join_init_read_record(join_tab)))
  {
    reset_cache(&join_tab->cache);
    join_tab->cache.records=0; join_tab->cache.ptr_record= (uint) ~0;
4527
    DBUG_RETURN(-error);			/* No records or error */
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  }

  for (JOIN_TAB *tmp=join->join_tab; tmp != join_tab ; tmp++)
  {
    tmp->status=tmp->table->status;
    tmp->table->status=0;
  }

  info= &join_tab->read_record;
  do
  {
    if (join->thd->killed)
    {
      my_error(ER_SERVER_SHUTDOWN,MYF(0)); /* purecov: inspected */
4542
      DBUG_RETURN(-2);				// Aborted by user /* purecov: inspected */
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    }
    SQL_SELECT *select=join_tab->select;
    if (!error && (!join_tab->cache.select ||
		   !join_tab->cache.select->skipp_record()))
    {
      uint i;
      reset_cache(&join_tab->cache);
      for (i=(join_tab->cache.records- (skipp_last ? 1 : 0)) ; i-- > 0 ;)
      {
	read_cached_record(join_tab);
	if (!select || !select->skipp_record())
	  if ((error=(join_tab->next_select)(join,join_tab+1,0)) < 0)
4555
	    DBUG_RETURN(error); /* purecov: inspected */
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      }
    }
  } while (!(error=info->read_record(info)));

  if (skipp_last)
    read_cached_record(join_tab);		// Restore current record
  reset_cache(&join_tab->cache);
  join_tab->cache.records=0; join_tab->cache.ptr_record= (uint) ~0;
  if (error > 0)				// Fatal error
4565
    DBUG_RETURN(-1);					/* purecov: inspected */
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  for (JOIN_TAB *tmp2=join->join_tab; tmp2 != join_tab ; tmp2++)
    tmp2->table->status=tmp2->status;
4568
  DBUG_RETURN(0);
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}


/*****************************************************************************
4573 4574
  The different ways to read a record
  Returns -1 if row was not found, 0 if row was found and 1 on errors
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*****************************************************************************/
static int
4577
join_read_const_table(JOIN_TAB *tab, POSITION *pos)
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{
  int error;
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  DBUG_ENTER("join_read_const_table");
  TABLE *table=tab->table;
  table->const_table=1;
  table->null_row=0;
  table->status=STATUS_NO_RECORD;
  
  if (tab->type == JT_SYSTEM)
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  {
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    if ((error=join_read_system(tab)))
    {						// Info for DESCRIBE
      tab->info="const row not found";
      /* Mark for EXPLAIN that the row was not found */
      pos->records_read=0.0;
      if (!table->outer_join || error > 0)
	DBUG_RETURN(error);
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    }
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  }
  else
  {
    if ((error=join_read_const(tab)))
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    {
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      tab->info="unique row not found";
      /* Mark for EXPLAIN that the row was not found */
      pos->records_read=0.0;
      if (!table->outer_join || error > 0)
	DBUG_RETURN(error);
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    }
  }
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  if (tab->on_expr && !table->null_row)
  {
    if ((table->null_row= test(tab->on_expr->val_int() == 0)))
      empty_record(table);
    }
  if (!table->null_row)
    table->maybe_null=0;
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  DBUG_RETURN(0);
}


static int
join_read_system(JOIN_TAB *tab)
{
  TABLE *table= tab->table;
  int error;
4624 4625
  DBUG_ENTER("join_read_system");

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  if (table->status & STATUS_GARBAGE)		// If first read
  {
4628 4629
    if ((error=table->file->read_first_row(table->record[0],
					   table->primary_key)))
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    {
      if (error != HA_ERR_END_OF_FILE)
      {
	table->file->print_error(error,MYF(0));
4634
	DBUG_RETURN(1);
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      }
      table->null_row=1;			// This is ok.
      empty_record(table);			// Make empty record
4638
      DBUG_RETURN(-1);
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    }
    store_record(table,1);
  }
  else if (!table->status)			// Only happens with left join
    restore_record(table,1);			// restore old record
  table->null_row=0;
4645
  DBUG_RETURN(table->status ? -1 : 0);
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}


static int
join_read_const(JOIN_TAB *tab)
{
  int error;
  TABLE *table= tab->table;
4654 4655
  DBUG_ENTER("join_read_const");

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  if (table->status & STATUS_GARBAGE)		// If first read
  {
    if (cp_buffer_from_ref(&tab->ref))
      error=HA_ERR_KEY_NOT_FOUND;
    else
    {
      error=table->file->index_read_idx(table->record[0],tab->ref.key,
					(byte*) tab->ref.key_buff,
					tab->ref.key_length,HA_READ_KEY_EXACT);
    }
    if (error)
    {
      table->null_row=1;
      empty_record(table);
      if (error != HA_ERR_KEY_NOT_FOUND)
      {
	sql_print_error("read_const: Got error %d when reading table %s",
4673
			error, table->path);
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	table->file->print_error(error,MYF(0));
4675
	DBUG_RETURN(1);
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      }
4677
      DBUG_RETURN(-1);
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    }
    store_record(table,1);
  }
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  else if (!(table->status & ~STATUS_NULL_ROW))	// Only happens with left join
  {
    table->status=0;
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    restore_record(table,1);			// restore old record
4685
  }
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  table->null_row=0;
4687
  DBUG_RETURN(table->status ? -1 : 0);
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}


static int
join_read_key(JOIN_TAB *tab)
{
  int error;
  TABLE *table= tab->table;
4696
  DBUG_ENTER("join_read_key");
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  if (cmp_buffer_with_ref(tab) ||
4699
      (table->status & (STATUS_GARBAGE | STATUS_NO_PARENT | STATUS_NULL_ROW)))
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  {
    if (tab->ref.key_err)
    {
      table->status=STATUS_NOT_FOUND;
4704
      DBUG_RETURN(-1);
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    }
    error=table->file->index_read(table->record[0],
				  tab->ref.key_buff,
				  tab->ref.key_length,HA_READ_KEY_EXACT);
    if (error && error != HA_ERR_KEY_NOT_FOUND)
    {
      sql_print_error("read_key: Got error %d when reading table '%s'",error,
4712
		      table->path);
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      table->file->print_error(error,MYF(0));
4714
      DBUG_RETURN(1);
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    }
  }
4717
  table->null_row=0;
4718
  DBUG_RETURN(table->status ? -1 : 0);
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}


static int
join_read_always_key(JOIN_TAB *tab)
{
  int error;
  TABLE *table= tab->table;
4727
  DBUG_ENTER("join_read_always_key");
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  if (cp_buffer_from_ref(&tab->ref))
4730
    DBUG_RETURN(-1);
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  if ((error=table->file->index_read(table->record[0],
				     tab->ref.key_buff,
				     tab->ref.key_length,HA_READ_KEY_EXACT)))
  {
    if (error != HA_ERR_KEY_NOT_FOUND)
    {
      sql_print_error("read_const: Got error %d when reading table %s",error,
4738
		      table->path);
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      table->file->print_error(error,MYF(0));
4740
      DBUG_RETURN(1);
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    }
4742
    DBUG_RETURN(-1); /* purecov: inspected */
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  }
4744
  DBUG_RETURN(0);
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}

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/*
  This function is used when optimizing away ORDER BY in 
  SELECT * FROM t1 WHERE a=1 ORDER BY a DESC,b DESC
*/
  
static int
join_read_last_key(JOIN_TAB *tab)
{
  int error;
  TABLE *table= tab->table;
4757
  DBUG_ENTER("join_read_last_key");
4758 4759

  if (cp_buffer_from_ref(&tab->ref))
4760
    DBUG_RETURN(-1);
4761 4762 4763 4764 4765 4766 4767 4768 4769
  if ((error=table->file->index_read_last(table->record[0],
					  tab->ref.key_buff,
					  tab->ref.key_length)))
  {
    if (error != HA_ERR_KEY_NOT_FOUND)
    {
      sql_print_error("read_const: Got error %d when reading table %s",error,
		      table->path);
      table->file->print_error(error,MYF(0));
4770
      DBUG_RETURN(1);
4771
    }
4772
    DBUG_RETURN(-1); /* purecov: inspected */
4773
  }
4774
  DBUG_RETURN(0);
4775 4776
}

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	/* ARGSUSED */
static int
join_no_more_records(READ_RECORD *info __attribute__((unused)))
{
4782 4783
  DBUG_ENTER("join_no_more_records");
  DBUG_RETURN(-1);
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}


static int
4788
join_read_next_same(READ_RECORD *info)
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{
  int error;
  TABLE *table= info->table;
  JOIN_TAB *tab=table->reginfo.join_tab;
4793
  DBUG_ENTER("join_read_next_same");
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  if ((error=table->file->index_next_same(table->record[0],
					  tab->ref.key_buff,
					  tab->ref.key_length)))
  {
    if (error != HA_ERR_END_OF_FILE)
    {
      sql_print_error("read_next: Got error %d when reading table %s",error,
4802
		      table->path);
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      table->file->print_error(error,MYF(0));
4804
      DBUG_RETURN(1);
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    }
    table->status= STATUS_GARBAGE;
4807
    DBUG_RETURN(-1);
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  }
4809
  DBUG_RETURN(0);
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}

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static int
join_read_prev_same(READ_RECORD *info)
{
  int error;
  TABLE *table= info->table;
  JOIN_TAB *tab=table->reginfo.join_tab;
4818
  DBUG_ENTER("join_read_prev_same");
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  if ((error=table->file->index_prev(table->record[0])))
  {
    if (error != HA_ERR_END_OF_FILE)
    {
      sql_print_error("read_next: Got error %d when reading table %s",error,
		      table->path);
      table->file->print_error(error,MYF(0));
      error= 1;
    }
    else
    {
      table->status= STATUS_GARBAGE;
      error= -1;
    }
  }
  else if (key_cmp(table, tab->ref.key_buff, tab->ref.key,
		   tab->ref.key_length))
  {
    table->status=STATUS_NOT_FOUND;
4839
    error= -1;
4840
  }
4841
  DBUG_RETURN(error);
4842 4843
}

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static int
join_init_quick_read_record(JOIN_TAB *tab)
{
4848 4849
  DBUG_ENTER("join_init_quick_read_record");

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  if (test_if_quick_select(tab) == -1)
4851 4852
    DBUG_RETURN(-1);					/* No possible records */
  DBUG_RETURN(join_init_read_record(tab));
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}


static int
test_if_quick_select(JOIN_TAB *tab)
{
  delete tab->select->quick;
4860 4861
  DBUG_ENTER("test_if_quick_select");

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  tab->select->quick=0;
4863
  DBUG_RETURN(tab->select->test_quick_select(tab->keys,(table_map) 0,HA_POS_ERROR));
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}


static int
join_init_read_record(JOIN_TAB *tab)
{
4870 4871
  DBUG_ENTER("join_init_read_record");

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  if (tab->select && tab->select->quick)
    tab->select->quick->reset();
4874 4875
  init_read_record(&tab->read_record, tab->join->thd, tab->table,
		   tab->select,1,1);
4876
  DBUG_RETURN((*tab->read_record.read_record)(&tab->read_record));
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}

static int
4880
join_read_first(JOIN_TAB *tab)
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{
  int error;
  TABLE *table=tab->table;
4884 4885
  DBUG_ENTER("join_read_first");

4886 4887
  if (!table->key_read && (table->used_keys & ((key_map) 1 << tab->index)) &&
      !table->no_keyread)
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  {
    table->key_read=1;
    table->file->extra(HA_EXTRA_KEYREAD);
  }
  tab->table->status=0;
4893
  tab->read_record.read_record=join_read_next;
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  tab->read_record.table=table;
  tab->read_record.file=table->file;
  tab->read_record.index=tab->index;
  tab->read_record.record=table->record[0];
  error=tab->table->file->index_first(tab->table->record[0]);
  if (error)
  {
    if (error != HA_ERR_KEY_NOT_FOUND && error != HA_ERR_END_OF_FILE)
    {
4903 4904
      sql_print_error("read_first_with_key: Got error %d when reading table",
		      error);
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      table->file->print_error(error,MYF(0));
4906
      DBUG_RETURN(1);
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    }
4908
    DBUG_RETURN(-1);
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  }
4910
  DBUG_RETURN(0);
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}

4913

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static int
4915
join_read_next(READ_RECORD *info)
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{
  int error=info->file->index_next(info->record);
4918 4919
  DBUG_ENTER("join_read_next");

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  if (error)
  {
    if (error != HA_ERR_END_OF_FILE)
    {
      sql_print_error("read_next_with_key: Got error %d when reading table %s",
4925
		      error, info->table->path);
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      info->file->print_error(error,MYF(0));
4927
      DBUG_RETURN(1);
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    }
4929
    DBUG_RETURN(-1);
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  }
4931
  DBUG_RETURN(0);
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}

static int
4935
join_read_last(JOIN_TAB *tab)
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{
  TABLE *table=tab->table;
  int error;
4939 4940
  DBUG_ENTER("join_read_last");

4941 4942
  if (!table->key_read && (table->used_keys & ((key_map) 1 << tab->index)) &&
      !table->no_keyread)
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  {
    table->key_read=1;
    table->file->extra(HA_EXTRA_KEYREAD);
  }
  tab->table->status=0;
4948
  tab->read_record.read_record=join_read_prev;
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  tab->read_record.table=table;
  tab->read_record.file=table->file;
  tab->read_record.index=tab->index;
  tab->read_record.record=table->record[0];
  error=tab->table->file->index_last(tab->table->record[0]);
  if (error)
  {
    if (error != HA_ERR_END_OF_FILE)
    {
4958
      sql_print_error("read_last_with_key: Got error %d when reading table",
4959
		      error, table->path);
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      table->file->print_error(error,MYF(0));
4961
      DBUG_RETURN(1);
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    }
4963
    DBUG_RETURN(-1);
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  }
4965
  DBUG_RETURN(0);
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}

4968

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static int
4970
join_read_prev(READ_RECORD *info)
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{
  int error=info->file->index_prev(info->record);
4973 4974
  DBUG_ENTER("join_read_prev");

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  if (error)
  {
    if (error != HA_ERR_END_OF_FILE)
    {
      sql_print_error("read_prev_with_key: Got error %d when reading table: %s",
4980
		      error,info->table->path);
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      info->file->print_error(error,MYF(0));
4982
      DBUG_RETURN(1);
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    }
4984
    DBUG_RETURN(-1);
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  }
4986
  DBUG_RETURN(0);
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}

4989

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static int
join_ft_read_first(JOIN_TAB *tab)
{
  int error;
  TABLE *table= tab->table;
4995
  DBUG_ENTER("join_ft_read_first");
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#if NOT_USED_YET
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  if (cp_buffer_from_ref(&tab->ref))       // as ft-key doesn't use store_key's
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    DBUG_RETURN(-1);                             // see also FT_SELECT::init()
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#endif
5001
  table->file->ft_init();
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  error=table->file->ft_read(table->record[0]);
  if (error)
  {
    if (error != HA_ERR_END_OF_FILE)
    {
5008
      sql_print_error("ft_read_first: Got error %d when reading table %s",
5009
                      error, table->path);
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      table->file->print_error(error,MYF(0));
5011
      DBUG_RETURN(1);
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    }
5013
    DBUG_RETURN(-1);
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  }
5015
  DBUG_RETURN(0);
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}

static int
join_ft_read_next(READ_RECORD *info)
{
  int error=info->file->ft_read(info->table->record[0]);
5022 5023
  DBUG_ENTER("join_ft_read_next");

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  if (error)
  {
    if (error != HA_ERR_END_OF_FILE)
    {
      sql_print_error("ft_read_next: Got error %d when reading table %s",
5029
                      error, info->table->path);
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      info->file->print_error(error,MYF(0));
5031
      DBUG_RETURN(1);
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    }
5033
    DBUG_RETURN(-1);
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  }
5035
  DBUG_RETURN(0);
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}


/*****************************************************************************
5040 5041 5042
  The different end of select functions
  These functions returns < 0 when end is reached, 0 on ok and > 0 if a
  fatal error (like table corruption) was detected
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*****************************************************************************/

5045
/* ARGSUSED */
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static int
end_send(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
	 bool end_of_records)
{
  DBUG_ENTER("end_send");
  if (!end_of_records)
  {
    int error;
5054
    if (join->having && join->having->val_int() == 0)
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      DBUG_RETURN(0);				// Didn't match having
5056
    error=0;
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    if (join->procedure)
      error=join->procedure->send_row(*join->fields);
5059
    else if (join->do_send_rows)
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      error=join->result->send_data(*join->fields);
    if (error)
      DBUG_RETURN(-1); /* purecov: inspected */
5063 5064
    if (++join->send_records >= join->thd->select_limit &&
	join->do_send_rows)
5065 5066 5067
    {
      if (join->select_options & OPTION_FOUND_ROWS)
      {
5068
	JOIN_TAB *jt=join->join_tab;
5069
	if ((join->tables == 1) && !join->tmp_table && !join->sort_and_group
5070
	    && !join->send_group_parts && !join->having && !jt->select_cond &&
5071
	    !(jt->select && jt->select->quick) &&
5072
	    !(jt->table->file->table_flags() & HA_NOT_EXACT_COUNT))
5073
	{
5074
	  /* Join over all rows in table;  Return number of found rows */
5075 5076
	  TABLE *table=jt->table;

5077
	  join->select_options ^= OPTION_FOUND_ROWS;
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	  if (table->record_pointers ||
	      (table->io_cache && my_b_inited(table->io_cache)))
	  {
	    /* Using filesort */
	    join->send_records= table->found_records;
	  }
	  else
	  {
	    table->file->info(HA_STATUS_VARIABLE);
	    join->send_records = table->file->records;
	  }
5089 5090 5091 5092 5093 5094 5095
	}
	else 
	{
	  join->do_send_rows=0;
	  join->thd->select_limit = HA_POS_ERROR;
	  DBUG_RETURN(0);
	}
5096
      }
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      DBUG_RETURN(-3);				// Abort nicely
5098
    }
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  }
  else
  {
    if (join->procedure && join->procedure->end_of_records())
      DBUG_RETURN(-1);
  }
  DBUG_RETURN(0);
}


	/* ARGSUSED */
static int
end_send_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
	       bool end_of_records)
{
  int idx= -1;
  DBUG_ENTER("end_send_group");

  if (!join->first_record || end_of_records ||
      (idx=test_if_group_changed(join->group_fields)) >= 0)
  {
    if (join->first_record || (end_of_records && !join->group))
    {
      if (join->procedure)
	join->procedure->end_group();
      if (idx < (int) join->send_group_parts)
      {
5126
	int error=0;
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	if (join->procedure)
	{
5129
	  if (join->having && join->having->val_int() == 0)
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	    error= -1;				// Didn't satisfy having
5131
 	  else if (join->do_send_rows)
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	    error=join->procedure->send_row(*join->fields) ? 1 : 0;
	  if (end_of_records && join->procedure->end_of_records())
	    error= 1;				// Fatal error
	}
	else
	{
	  if (!join->first_record)
5139 5140
	  {
	    /* No matching rows for group function */
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	    clear_tables(join);
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	    copy_fields(&join->tmp_table_param);
	  }
5144
	  if (join->having && join->having->val_int() == 0)
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	    error= -1;				// Didn't satisfy having
5146
	  else if (join->do_send_rows)
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	    error=join->result->send_data(*join->fields) ? 1 : 0;
	}
	if (error > 0)
	  DBUG_RETURN(-1);			/* purecov: inspected */
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	if (end_of_records)
	{
	  join->send_records++;
	  DBUG_RETURN(0);
	}
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	if (!error &&
	    ++join->send_records >= join->thd->select_limit &&
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	    join->do_send_rows)
	{
	  if (!(join->select_options & OPTION_FOUND_ROWS))
	    DBUG_RETURN(-3);				// Abort nicely
	  join->do_send_rows=0;
	  join->thd->select_limit = HA_POS_ERROR;
        }
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      }
    }
    else
    {
      if (end_of_records)
	DBUG_RETURN(0);
      join->first_record=1;
      VOID(test_if_group_changed(join->group_fields));
    }
    if (idx < (int) join->send_group_parts)
    {
      copy_fields(&join->tmp_table_param);
      init_sum_functions(join->sum_funcs);
      if (join->procedure)
	join->procedure->add();
      DBUG_RETURN(0);
    }
  }
  if (update_sum_func(join->sum_funcs))
    DBUG_RETURN(-1);
  if (join->procedure)
    join->procedure->add();
  DBUG_RETURN(0);
}


	/* ARGSUSED */
static int
end_write(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
	  bool end_of_records)
{
  TABLE *table=join->tmp_table;
  int error;
  DBUG_ENTER("end_write");

  if (join->thd->killed)			// Aborted by user
  {
    my_error(ER_SERVER_SHUTDOWN,MYF(0));	/* purecov: inspected */
    DBUG_RETURN(-2);				/* purecov: inspected */
  }
  if (!end_of_records)
  {
    copy_fields(&join->tmp_table_param);
    copy_funcs(join->tmp_table_param.funcs);

5210
#ifdef TO_BE_DELETED
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    if (!table->uniques)			// If not unique handling
    {
      /* Copy null values from group to row */
      ORDER   *group;
      for (group=table->group ; group ; group=group->next)
      {
	Item *item= *group->item;
	if (item->maybe_null)
	{
	  Field *field=item->tmp_table_field();
5221
	  field->ptr[-1]= (byte) (field->is_null() ? 1 : 0);
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	}
      }
    }
5225
#endif
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    if (!join->having || join->having->val_int())
    {
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      join->found_records++;
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      if ((error=table->file->write_row(table->record[0])))
      {
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	if (error == HA_ERR_FOUND_DUPP_KEY ||
	    error == HA_ERR_FOUND_DUPP_UNIQUE)
	  goto end;
	if (create_myisam_from_heap(table, &join->tmp_table_param, error,1))
5235
	  DBUG_RETURN(-1);			// Not a table_is_full error
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	table->uniques=0;			// To ensure rows are the same
5237
      }
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      if (++join->send_records >= join->tmp_table_param.end_write_records &&
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	  join->do_send_rows)
      {
	if (!(join->select_options & OPTION_FOUND_ROWS))
	  DBUG_RETURN(-3);
	join->do_send_rows=0;
	join->thd->select_limit = HA_POS_ERROR;
	DBUG_RETURN(0);
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      }
    }
  }
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end:
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  DBUG_RETURN(0);
}

/* Group by searching after group record and updating it if possible */
/* ARGSUSED */

static int
end_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
	   bool end_of_records)
{
  TABLE *table=join->tmp_table;
  ORDER   *group;
  int	  error;
  DBUG_ENTER("end_update");

  if (end_of_records)
    DBUG_RETURN(0);
  if (join->thd->killed)			// Aborted by user
  {
    my_error(ER_SERVER_SHUTDOWN,MYF(0));	/* purecov: inspected */
    DBUG_RETURN(-2);				/* purecov: inspected */
  }

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  join->found_records++;
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  copy_fields(&join->tmp_table_param);		// Groups are copied twice.
  /* Make a key of group index */
  for (group=table->group ; group ; group=group->next)
  {
    Item *item= *group->item;
    item->save_org_in_field(group->field);
5280
    /* Store in the used key if the field was 0 */
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    if (item->maybe_null)
5282
      group->buff[-1]=item->null_value ? 1 : 0;
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  }
  // table->file->index_init(0);
  if (!table->file->index_read(table->record[1],
			       join->tmp_table_param.group_buff,0,
			       HA_READ_KEY_EXACT))
  {						/* Update old record */
    restore_record(table,1);
    update_tmptable_sum_func(join->sum_funcs,table);
    if ((error=table->file->update_row(table->record[1],
				       table->record[0])))
    {
      table->file->print_error(error,MYF(0));	/* purecov: inspected */
      DBUG_RETURN(-1);				/* purecov: inspected */
    }
    DBUG_RETURN(0);
  }

  /* The null bits are already set */
  KEY_PART_INFO *key_part;
  for (group=table->group,key_part=table->key_info[0].key_part;
       group ;
       group=group->next,key_part++)
    memcpy(table->record[0]+key_part->offset, group->buff, key_part->length);

  init_tmptable_sum_functions(join->sum_funcs);
  copy_funcs(join->tmp_table_param.funcs);
  if ((error=table->file->write_row(table->record[0])))
  {
    if (create_myisam_from_heap(table, &join->tmp_table_param, error, 0))
      DBUG_RETURN(-1);				// Not a table_is_full error
    /* Change method to update rows */
    table->file->index_init(0);
    join->join_tab[join->tables-1].next_select=end_unique_update;
  }
  join->send_records++;
  DBUG_RETURN(0);
}

/* Like end_update, but this is done with unique constraints instead of keys */

static int
end_unique_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
		  bool end_of_records)
{
  TABLE *table=join->tmp_table;
  int	  error;
  DBUG_ENTER("end_unique_update");

  if (end_of_records)
    DBUG_RETURN(0);
  if (join->thd->killed)			// Aborted by user
  {
    my_error(ER_SERVER_SHUTDOWN,MYF(0));	/* purecov: inspected */
    DBUG_RETURN(-2);				/* purecov: inspected */
  }

  init_tmptable_sum_functions(join->sum_funcs);
  copy_fields(&join->tmp_table_param);		// Groups are copied twice.
  copy_funcs(join->tmp_table_param.funcs);

  if (!(error=table->file->write_row(table->record[0])))
    join->send_records++;			// New group
  else
  {
    if ((int) table->file->get_dup_key(error) < 0)
    {
      table->file->print_error(error,MYF(0));	/* purecov: inspected */
      DBUG_RETURN(-1);				/* purecov: inspected */
    }
    if (table->file->rnd_pos(table->record[1],table->file->dupp_ref))
    {
      table->file->print_error(error,MYF(0));	/* purecov: inspected */
      DBUG_RETURN(-1);				/* purecov: inspected */
    }
    restore_record(table,1);
    update_tmptable_sum_func(join->sum_funcs,table);
    if ((error=table->file->update_row(table->record[1],
				       table->record[0])))
    {
      table->file->print_error(error,MYF(0));	/* purecov: inspected */
      DBUG_RETURN(-1);				/* purecov: inspected */
    }
  }
  DBUG_RETURN(0);
}


	/* ARGSUSED */
static int
end_write_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
		bool end_of_records)
{
  TABLE *table=join->tmp_table;
  int	  error;
  int	  idx= -1;
  DBUG_ENTER("end_write_group");

  if (join->thd->killed)
  {						// Aborted by user
    my_error(ER_SERVER_SHUTDOWN,MYF(0));	/* purecov: inspected */
    DBUG_RETURN(-2);				/* purecov: inspected */
  }
  if (!join->first_record || end_of_records ||
      (idx=test_if_group_changed(join->group_fields)) >= 0)
  {
    if (join->first_record || (end_of_records && !join->group))
    {
      if (join->procedure)
	join->procedure->end_group();
      if (idx < (int) join->send_group_parts)
      {
	if (!join->first_record)
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	{
	  /* No matching rows for group function */
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	  clear_tables(join);
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	  copy_fields(&join->tmp_table_param);
	}
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	copy_sum_funcs(join->sum_funcs);
	if (!join->having || join->having->val_int())
	{
	  if ((error=table->file->write_row(table->record[0])))
	  {
	    if (create_myisam_from_heap(table, &join->tmp_table_param,
					error, 0))
5407
	      DBUG_RETURN(-1);			// Not a table_is_full error
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	  }
	  else
	    join->send_records++;
	}
	if (end_of_records)
	  DBUG_RETURN(0);
      }
    }
    else
    {
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      if (end_of_records)
	DBUG_RETURN(0);
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      join->first_record=1;
      VOID(test_if_group_changed(join->group_fields));
    }
    if (idx < (int) join->send_group_parts)
    {
      copy_fields(&join->tmp_table_param);
      copy_funcs(join->tmp_table_param.funcs);
      init_sum_functions(join->sum_funcs);
      if (join->procedure)
	join->procedure->add();
      DBUG_RETURN(0);
    }
  }
  if (update_sum_func(join->sum_funcs))
    DBUG_RETURN(-1);
  if (join->procedure)
    join->procedure->add();
  DBUG_RETURN(0);
}


/*****************************************************************************
5442 5443 5444 5445 5446
  Remove calculation with tables that aren't yet read. Remove also tests
  against fields that are read through key where the table is not a
  outer join table.
  We can't remove tests that are made against columns which are stored
  in sorted order.
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*****************************************************************************/

/* Return 1 if right_item is used removable reference key on left_item */

static bool test_if_ref(Item_field *left_item,Item *right_item)
{
  Field *field=left_item->field;
5454 5455
  DBUG_ENTER("test_if_ref");

5456 5457
  // No need to change const test. We also have to keep tests on LEFT JOIN
  if (!field->table->const_table && !field->table->maybe_null)
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  {
    Item *ref_item=part_of_refkey(field->table,field);
5460
    if (ref_item && ref_item->eq(right_item,1))
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    {
      if (right_item->type() == Item::FIELD_ITEM)
5463
	DBUG_RETURN((field->eq_def(((Item_field *) right_item)->field)));
5464
      if (right_item->const_item() && !(right_item->is_null()))
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      {
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	/*
	  We can remove binary fields and numerical fields except float,
	  as float comparison isn't 100 % secure
	*/
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	if (field->binary() &&
	    (field->type() != FIELD_TYPE_FLOAT || field->decimals() == 0))
	{
5473
	  DBUG_RETURN(!store_val_in_field(field,right_item));
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	}
      }
    }
  }
5478
  DBUG_RETURN(0);					// keep test
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}


static COND *
make_cond_for_table(COND *cond,table_map tables,table_map used_table)
{
5485 5486
  DBUG_ENTER("make_cond_for_table");

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  if (used_table && !(cond->used_tables() & used_table))
5488
    DBUG_RETURN((COND*) 0);				// Already checked
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  if (cond->type() == Item::COND_ITEM)
  {
    if (((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
    {
      Item_cond_and *new_cond=new Item_cond_and;
      if (!new_cond)
5495
	DBUG_RETURN((COND*) 0);			// OOM /* purecov: inspected */
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      List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
      Item *item;
      while ((item=li++))
      {
	Item *fix=make_cond_for_table(item,tables,used_table);
	if (fix)
	  new_cond->argument_list()->push_back(fix);
      }
      switch (new_cond->argument_list()->elements) {
      case 0:
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	DBUG_RETURN((COND*) 0);			// Always true
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      case 1:
5508
	DBUG_RETURN(new_cond->argument_list()->head());
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      default:
	new_cond->used_tables_cache=((Item_cond*) cond)->used_tables_cache &
	  tables;
5512
	DBUG_RETURN(new_cond);
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      }
    }
    else
    {						// Or list
      Item_cond_or *new_cond=new Item_cond_or;
      if (!new_cond)
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	DBUG_RETURN((COND*) 0);			// OOM /* purecov: inspected */
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      List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
      Item *item;
      while ((item=li++))
      {
	Item *fix=make_cond_for_table(item,tables,0L);
	if (!fix)
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	  DBUG_RETURN((COND*) 0);			// Always true
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	new_cond->argument_list()->push_back(fix);
      }
      new_cond->used_tables_cache=((Item_cond_or*) cond)->used_tables_cache;
5530
      DBUG_RETURN(new_cond);
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    }
  }

  /*
5535 5536 5537
    Because the following test takes a while and it can be done
    table_count times, we mark each item that we have examined with the result
    of the test
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  */

  if (cond->marker == 3 || (cond->used_tables() & ~tables))
5541
    DBUG_RETURN((COND*) 0);				// Can't check this yet
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5542
  if (cond->marker == 2 || cond->eq_cmp_result() == Item::COND_OK)
5543
    DBUG_RETURN(cond);				// Not boolean op
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  if (((Item_func*) cond)->functype() == Item_func::EQ_FUNC)
  {
    Item *left_item=	((Item_func*) cond)->arguments()[0];
    Item *right_item= ((Item_func*) cond)->arguments()[1];
    if (left_item->type() == Item::FIELD_ITEM &&
	test_if_ref((Item_field*) left_item,right_item))
    {
      cond->marker=3;			// Checked when read
5553
      DBUG_RETURN((COND*) 0);
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    }
    if (right_item->type() == Item::FIELD_ITEM &&
	test_if_ref((Item_field*) right_item,left_item))
    {
      cond->marker=3;			// Checked when read
5559
      DBUG_RETURN((COND*) 0);
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    }
  }
  cond->marker=2;
5563
  DBUG_RETURN(cond);
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}

static Item *
part_of_refkey(TABLE *table,Field *field)
{
  uint ref_parts=table->reginfo.join_tab->ref.key_parts;
5570 5571
  DBUG_ENTER("part_of_refkey");

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  if (ref_parts)
  {
    KEY_PART_INFO *key_part=
      table->key_info[table->reginfo.join_tab->ref.key].key_part;

    for (uint part=0 ; part < ref_parts ; part++,key_part++)
      if (field->eq(key_part->field) &&
	  !(key_part->key_part_flag & HA_PART_KEY))
5580
	DBUG_RETURN(table->reginfo.join_tab->ref.items[part]);
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  }
5582
  DBUG_RETURN((Item*) 0);
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}


/*****************************************************************************
5587 5588 5589 5590 5591
  Test if one can use the key to resolve ORDER BY
  Returns: 1 if key is ok.
	   0 if key can't be used
	  -1 if reverse key can be used
          used_key_parts is set to key parts used if length != 0
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*****************************************************************************/

5594 5595
static int test_if_order_by_key(ORDER *order, TABLE *table, uint idx,
				uint *used_key_parts)
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{
  KEY_PART_INFO *key_part,*key_part_end;
5598 5599
  DBUG_ENTER("test_if_order_by_key");

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  key_part=table->key_info[idx].key_part;
  key_part_end=key_part+table->key_info[idx].key_parts;
  key_part_map const_key_parts=table->const_key_parts[idx];
  int reverse=0;

  for (; order ; order=order->next, const_key_parts>>=1)
  {
    Field *field=((Item_field*) (*order->item))->field;
    int flag;

    /*
      Skip key parts that are constants in the WHERE clause.
      These are already skipped in the ORDER BY by const_expression_in_where()
    */
    while (const_key_parts & 1)
    {
      key_part++; const_key_parts>>=1;
    }
    if (key_part == key_part_end || key_part->field != field)
5619
      DBUG_RETURN(0);
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    /* set flag to 1 if we can use read-next on key, else to -1 */
    flag=(order->asc == !(key_part->key_part_flag & HA_REVERSE_SORT))
      ? 1 : -1;
    if (reverse && flag != reverse)
5625
      DBUG_RETURN(0);
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    reverse=flag;				// Remember if reverse
    key_part++;
  }
5629
  *used_key_parts= (uint) (key_part - table->key_info[idx].key_part);
5630
  DBUG_RETURN(reverse);
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}

static uint find_shortest_key(TABLE *table, key_map usable_keys)
{
  uint min_length= (uint) ~0;
  uint best= MAX_KEY;
5637 5638
  DBUG_ENTER("find_shortest_key");

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  for (uint nr=0; usable_keys ; usable_keys>>=1, nr++)
  {
    if (usable_keys & 1)
    {
      if (table->key_info[nr].key_length < min_length)
      {
	min_length=table->key_info[nr].key_length;
	best=nr;
      }
    }
  }
5650
  DBUG_RETURN(best);
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}


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/*
  Test if we can skip the ORDER BY by using an index.

  If we can use an index, the JOIN_TAB / tab->select struct
  is changed to use the index.

  Return:
     0 We have to use filesort to do the sorting
     1 We can use an index.
*/
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static bool
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test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
			bool no_changes)
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{
  int ref_key;
  TABLE *table=tab->table;
  SQL_SELECT *select=tab->select;
  key_map usable_keys;
  DBUG_ENTER("test_if_skip_sort_order");

  /* Check which keys can be used to resolve ORDER BY */
  usable_keys= ~(key_map) 0;
  for (ORDER *tmp_order=order; tmp_order ; tmp_order=tmp_order->next)
  {
    if ((*tmp_order->item)->type() != Item::FIELD_ITEM)
    {
      usable_keys=0;
      break;
    }
5684
    usable_keys&=((Item_field*) (*tmp_order->item))->field->part_of_sortkey;
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  }

  ref_key= -1;
  if (tab->ref.key >= 0)			// Constant range in WHERE
    ref_key=tab->ref.key;
  else if (select && select->quick)		// Range found by opt_range
    ref_key=select->quick->index;

  if (ref_key >= 0)
  {
5695 5696 5697
    /*
      We come here when there is a REF key.
    */
5698
    int order_direction;
5699
    uint used_key_parts;
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    /* Check if we get the rows in requested sorted order by using the key */
    if ((usable_keys & ((key_map) 1 << ref_key)) &&
5702 5703
	(order_direction = test_if_order_by_key(order,table,ref_key,
						&used_key_parts)))
5704
    {
5705
      if (order_direction == -1)		// If ORDER BY ... DESC
5706
      {
5707 5708
	if (select && select->quick)
	{
5709 5710 5711 5712 5713
	  /*
	    Don't reverse the sort order, if it's already done.
	    (In some cases test_if_order_by_key() can be called multiple times
	  */
	  if (!select->quick->reverse_sorted())
5714
	  {
5715 5716 5717 5718 5719 5720 5721 5722 5723
	    // ORDER BY range_key DESC
	    QUICK_SELECT_DESC *tmp=new QUICK_SELECT_DESC(select->quick,
							 used_key_parts);
	    if (!tmp || tmp->error)
	    {
	      delete tmp;
	      DBUG_RETURN(0);		// Reverse sort not supported
	    }
	    select->quick=tmp;
5724 5725 5726 5727 5728 5729 5730
	  }
	  DBUG_RETURN(1);
	}
	if (tab->ref.key_parts < used_key_parts)
	{
	  /*
	    SELECT * FROM t1 WHERE a=1 ORDER BY a DESC,b DESC
5731 5732 5733

	    Use a traversal function that starts by reading the last row
	    with key part (A) and then traverse the index backwards.
5734
	  */
5735
	  if (table->file->index_flags(ref_key) & HA_NOT_READ_PREFIX_LAST)
5736
	    DBUG_RETURN(0);			// Use filesort
5737 5738 5739
	  tab->read_first_record=       join_read_last_key;
	  tab->read_record.read_record= join_read_prev_same;
	  /* fall through */
5740
	}
5741
      }
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5742
      DBUG_RETURN(1);			/* No need to sort */
5743
    }
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  }
  else
  {
    /* check if we can use a key to resolve the group */
    /* Tables using JT_NEXT are handled here */
    uint nr;
    key_map keys=usable_keys;

    /*
      If not used with LIMIT, only use keys if the whole query can be
      resolved with a key;  This is because filesort() is usually faster than
      retrieving all rows through an index.
    */
    if (select_limit >= table->file->records)
5758
      keys&= (table->used_keys | table->file->keys_to_use_for_scanning());
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    for (nr=0; keys ; keys>>=1, nr++)
    {
5762
      uint not_used;
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      if (keys & 1)
      {
	int flag;
5766
	if ((flag=test_if_order_by_key(order, table, nr, &not_used)))
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	{
5768 5769 5770
	  if (!no_changes)
	  {
	    tab->index=nr;
5771 5772
	    tab->read_first_record=  (flag > 0 ? join_read_first:
				      join_read_last);
5773 5774
	    table->file->index_init(nr);
	    tab->type=JT_NEXT;	// Read with index_first(), index_next()
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	    if (table->used_keys & ((key_map) 1 << nr))
	    {
	      table->key_read=1;
	      table->file->extra(HA_EXTRA_KEYREAD);
	    }
5780
	  }
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	  DBUG_RETURN(1);
	}
      }
    }
  }
  DBUG_RETURN(0);				// Can't use index.
}

5789 5790 5791 5792 5793 5794 5795 5796

/*****************************************************************************
  If not selecting by given key, create an index how records should be read
  return: 0  ok
	  -1 some fatal error
	   1  no records
*****************************************************************************/

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static int
5798 5799
create_sort_index(JOIN_TAB *tab, ORDER *order, ha_rows filesort_limit,
		  ha_rows select_limit)
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{
  SORT_FIELD *sortorder;
  uint length;
5803
  ha_rows examined_rows;
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  TABLE *table=tab->table;
  SQL_SELECT *select=tab->select;
  DBUG_ENTER("create_sort_index");

5808
  if (test_if_skip_sort_order(tab,order,select_limit,0))
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    DBUG_RETURN(0);
  if (!(sortorder=make_unireg_sortorder(order,&length)))
    goto err;				/* purecov: inspected */
  /* It's not fatal if the following alloc fails */
  table->io_cache=(IO_CACHE*) my_malloc(sizeof(IO_CACHE),
5814
					MYF(MY_WME | MY_ZEROFILL));
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  table->status=0;				// May be wrong if quick_select

  // If table has a range, move it to select
  if (select && !select->quick && tab->ref.key >= 0)
  {
    if (tab->quick)
    {
      select->quick=tab->quick;
      tab->quick=0;
      /* We can only use 'Only index' if quick key is same as ref_key */
      if (table->key_read && (uint) tab->ref.key != select->quick->index)
      {
	table->key_read=0;
	table->file->extra(HA_EXTRA_NO_KEYREAD);
      }
    }
    else
    {
      /*
	We have a ref on a const;  Change this to a range that filesort
	can use.
      */
5837
      if (!(select->quick=get_ft_or_quick_select_for_ref(table, tab)))
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	goto err;
    }
  }
5841 5842 5843
  if (table->tmp_table)
    table->file->info(HA_STATUS_VARIABLE);	// Get record count
  table->found_records=filesort(table,sortorder,length,
5844
				select, 0L, filesort_limit, &examined_rows);
5845
  tab->records=table->found_records;		// For SQL_CALC_ROWS
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  delete select;				// filesort did select
  tab->select=0;
  tab->select_cond=0;
  tab->type=JT_ALL;				// Read with normal read_record
  tab->read_first_record= join_init_read_record;
5851
  tab->join->examined_rows+=examined_rows;
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  if (table->key_read)				// Restore if we used indexes
  {
    table->key_read=0;
    table->file->extra(HA_EXTRA_NO_KEYREAD);
  }
  DBUG_RETURN(table->found_records == HA_POS_ERROR);
err:
  DBUG_RETURN(-1);
}

5862
/*
5863
  Add the HAVING criteria to table->select
5864 5865
*/

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#ifdef NOT_YET
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static bool fix_having(JOIN *join, Item **having)
{
5869 5870
  DBUG_ENTER("fix_having");

5871 5872 5873 5874
  (*having)->update_used_tables();	// Some tables may have been const
  JOIN_TAB *table=&join->join_tab[join->const_tables];
  table_map used_tables= join->const_table_map | table->table->map;

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  DBUG_EXECUTE("where",print_where(*having,"having"););
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  Item* sort_table_cond=make_cond_for_table(*having,used_tables,used_tables);
  if (sort_table_cond)
  {
    if (!table->select)
      if (!(table->select=new SQL_SELECT))
5881
	DBUG_RETURN(1);
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    if (!table->select->cond)
      table->select->cond=sort_table_cond;
    else					// This should never happen
      if (!(table->select->cond=new Item_cond_and(table->select->cond,
						  sort_table_cond)))
5887
	DBUG_RETURN(1);
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    table->select_cond=table->select->cond;
    DBUG_EXECUTE("where",print_where(table->select_cond,
				     "select and having"););
    *having=make_cond_for_table(*having,~ (table_map) 0,~used_tables);
    DBUG_EXECUTE("where",print_where(*having,"having after make_cond"););
  }
5894
  DBUG_RETURN(0);
5895
}
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#endif
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/*****************************************************************************
5900 5901 5902 5903 5904
  Remove duplicates from tmp table
  This should be recoded to add a unique index to the table and remove
  duplicates
  Table is a locked single thread table
  fields is the number of fields to check (from the end)
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*****************************************************************************/

static bool compare_record(TABLE *table, Field **ptr)
{
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  DBUG_ENTER("compare_record");

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  for (; *ptr ; ptr++)
  {
    if ((*ptr)->cmp_offset(table->rec_buff_length))
5914
      DBUG_RETURN(1);
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  }
5916
  DBUG_RETURN(0);
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}

static bool copy_blobs(Field **ptr)
{
5921 5922
  DBUG_ENTER("copy_blobs");

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  for (; *ptr ; ptr++)
  {
    if ((*ptr)->flags & BLOB_FLAG)
      if (((Field_blob *) (*ptr))->copy())
5927
	DBUG_RETURN(1);				// Error
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  }
5929
  DBUG_RETURN(0);
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}

static void free_blobs(Field **ptr)
{
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  DBUG_ENTER("free_blobs");

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  for (; *ptr ; ptr++)
  {
    if ((*ptr)->flags & BLOB_FLAG)
      ((Field_blob *) (*ptr))->free();
  }
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  DBUG_VOID_RETURN;
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}


static int
5946
remove_duplicates(JOIN *join, TABLE *entry,List<Item> &fields, Item *having)
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{
  int error;
  ulong reclength,offset;
  uint field_count;
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  THD *thd= current_thd;
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  DBUG_ENTER("remove_duplicates");

  entry->reginfo.lock_type=TL_WRITE;

  /* Calculate how many saved fields there is in list */
  field_count=0;
  List_iterator<Item> it(fields);
  Item *item;
  while ((item=it++))
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  {
    if (item->tmp_table_field() && ! item->const_item())
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      field_count++;
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  }
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  if (!field_count)
  {						// only const items
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    join->thd->select_limit=1;	// Only send first row
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    DBUG_RETURN(0);
  }
  Field **first_field=entry->field+entry->fields - field_count;
  offset=entry->field[entry->fields - field_count]->offset();
  reclength=entry->reclength-offset;

  free_io_cache(entry);				// Safety
  entry->file->info(HA_STATUS_VARIABLE);
  if (entry->db_type == DB_TYPE_HEAP ||
      (!entry->blob_fields &&
       ((ALIGN_SIZE(reclength) +sizeof(HASH_LINK)) * entry->file->records <
5980
	thd->variables.sortbuff_size)))
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    error=remove_dup_with_hash_index(join->thd, entry,
				     field_count, first_field,
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				     reclength, having);
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  else
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    error=remove_dup_with_compare(join->thd, entry, first_field, offset,
				  having);
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  free_blobs(first_field);
  DBUG_RETURN(error);
}


static int remove_dup_with_compare(THD *thd, TABLE *table, Field **first_field,
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				   ulong offset, Item *having)
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{
  handler *file=table->file;
  char *org_record,*new_record;
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  byte *record;
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  int error;
  ulong reclength=table->reclength-offset;
  DBUG_ENTER("remove_dup_with_compare");

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  org_record=(char*) (record=table->record[0])+offset;
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  new_record=(char*) table->record[1]+offset;

  file->rnd_init();
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  error=file->rnd_next(record);
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  for (;;)
  {
    if (thd->killed)
    {
      my_error(ER_SERVER_SHUTDOWN,MYF(0));
      error=0;
      goto err;
    }
    if (error)
    {
      if (error == HA_ERR_RECORD_DELETED)
	continue;
      if (error == HA_ERR_END_OF_FILE)
	break;
      goto err;
    }
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    if (having && !having->val_int())
    {
      if ((error=file->delete_row(record)))
	goto err;
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      error=file->rnd_next(record);
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      continue;
    }
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    if (copy_blobs(first_field))
    {
      my_error(ER_OUT_OF_SORTMEMORY,MYF(0));
      error=0;
      goto err;
    }
    memcpy(new_record,org_record,reclength);

    /* Read through rest of file and mark duplicated rows deleted */
    bool found=0;
    for (;;)
    {
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      if ((error=file->rnd_next(record)))
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      {
	if (error == HA_ERR_RECORD_DELETED)
	  continue;
	if (error == HA_ERR_END_OF_FILE)
	  break;
	goto err;
      }
      if (compare_record(table, first_field) == 0)
      {
6053
	if ((error=file->delete_row(record)))
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	  goto err;
      }
      else if (!found)
      {
	found=1;
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	file->position(record);	// Remember position
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      }
    }
    if (!found)
      break;					// End of file
    /* Restart search on next row */
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    error=file->restart_rnd_next(record,file->ref);
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  }

  file->extra(HA_EXTRA_NO_CACHE);
  DBUG_RETURN(0);
err:
  file->extra(HA_EXTRA_NO_CACHE);
  if (error)
    file->print_error(error,MYF(0));
  DBUG_RETURN(1);
}


/*
  Generate a hash index for each row to quickly find duplicate rows
  Note that this will not work on tables with blobs!
*/

static int remove_dup_with_hash_index(THD *thd, TABLE *table,
				      uint field_count,
				      Field **first_field,
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				      ulong key_length,
				      Item *having)
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{
  byte *key_buffer, *key_pos, *record=table->record[0];
  int error;
  handler *file=table->file;
  ulong extra_length=ALIGN_SIZE(key_length)-key_length;
  uint *field_lengths,*field_length;
  HASH hash;
  DBUG_ENTER("remove_dup_with_hash_index");

  if (!my_multi_malloc(MYF(MY_WME),
		       &key_buffer,
		       (uint) ((key_length + extra_length) *
			       (long) file->records),
		       &field_lengths,
		       (uint) (field_count*sizeof(*field_lengths)),
		       NullS))
    DBUG_RETURN(1);
  if (hash_init(&hash, (uint) file->records, 0, key_length,
		(hash_get_key) 0, 0, 0))
  {
    my_free((char*) key_buffer,MYF(0));
    DBUG_RETURN(1);
  }
  {
    Field **ptr;
    for (ptr= first_field, field_length=field_lengths ; *ptr ; ptr++)
      (*field_length++)= (*ptr)->pack_length();
  }

  file->rnd_init();
  key_pos=key_buffer;
  for (;;)
  {
    if (thd->killed)
    {
      my_error(ER_SERVER_SHUTDOWN,MYF(0));
      error=0;
      goto err;
    }
    if ((error=file->rnd_next(record)))
    {
      if (error == HA_ERR_RECORD_DELETED)
	continue;
      if (error == HA_ERR_END_OF_FILE)
	break;
      goto err;
    }
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    if (having && !having->val_int())
    {
      if ((error=file->delete_row(record)))
	goto err;
      continue;
6140
    }
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    /* copy fields to key buffer */
    field_length=field_lengths;
    for (Field **ptr= first_field ; *ptr ; ptr++)
    {
      (*ptr)->sort_string((char*) key_pos,*field_length);
      key_pos+= *field_length++;
    }
    /* Check if it exists before */
    if (hash_search(&hash,key_pos-key_length,key_length))
    {
      /* Duplicated found ; Remove the row */
      if ((error=file->delete_row(record)))
	goto err;
    }
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    else
      (void) hash_insert(&hash, key_pos-key_length);
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    key_pos+=extra_length;
  }
  my_free((char*) key_buffer,MYF(0));
  hash_free(&hash);
  file->extra(HA_EXTRA_NO_CACHE);
  (void) file->rnd_end();
  DBUG_RETURN(0);

err:
  my_free((char*) key_buffer,MYF(0));
  hash_free(&hash);
  file->extra(HA_EXTRA_NO_CACHE);
  (void) file->rnd_end();
  if (error)
    file->print_error(error,MYF(0));
  DBUG_RETURN(1);
}


6177
SORT_FIELD *make_unireg_sortorder(ORDER *order, uint *length)
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{
  uint count;
  SORT_FIELD *sort,*pos;
  DBUG_ENTER("make_unireg_sortorder");

  count=0;
  for (ORDER *tmp = order; tmp; tmp=tmp->next)
    count++;
  pos=sort=(SORT_FIELD*) sql_alloc(sizeof(SORT_FIELD)*(count+1));
  if (!pos)
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    DBUG_RETURN(0);
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  for (;order;order=order->next,pos++)
  {
    pos->field=0; pos->item=0;
    if (order->item[0]->type() == Item::FIELD_ITEM)
      pos->field= ((Item_field*) (*order->item))->field;
    else if (order->item[0]->type() == Item::SUM_FUNC_ITEM &&
	     !order->item[0]->const_item())
      pos->field= ((Item_sum*) order->item[0])->tmp_table_field();
    else if (order->item[0]->type() == Item::COPY_STR_ITEM)
    {						// Blob patch
      pos->item= ((Item_copy_string*) (*order->item))->item;
    }
    else
      pos->item= *order->item;
    pos->reverse=! order->asc;
  }
  *length=count;
  DBUG_RETURN(sort);
}


/*****************************************************************************
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  Fill join cache with packed records
  Records are stored in tab->cache.buffer and last record in
  last record is stored with pointers to blobs to support very big
  records
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******************************************************************************/

static int
join_init_cache(THD *thd,JOIN_TAB *tables,uint table_count)
{
  reg1 uint i;
  uint length,blobs,size;
  CACHE_FIELD *copy,**blob_ptr;
  JOIN_CACHE  *cache;
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  JOIN_TAB *join_tab;
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  DBUG_ENTER("join_init_cache");

  cache= &tables[table_count].cache;
  cache->fields=blobs=0;

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  join_tab=tables;
  for (i=0 ; i < table_count ; i++,join_tab++)
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  {
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    if (!join_tab->used_fieldlength)		/* Not calced yet */
      calc_used_field_length(thd, join_tab);
    cache->fields+=join_tab->used_fields;
    blobs+=join_tab->used_blobs;
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  }
  if (!(cache->field=(CACHE_FIELD*)
	sql_alloc(sizeof(CACHE_FIELD)*(cache->fields+table_count*2)+(blobs+1)*
		  sizeof(CACHE_FIELD*))))
  {
    my_free((gptr) cache->buff,MYF(0));		/* purecov: inspected */
    cache->buff=0;				/* purecov: inspected */
    DBUG_RETURN(1);				/* purecov: inspected */
  }
  copy=cache->field;
  blob_ptr=cache->blob_ptr=(CACHE_FIELD**)
    (cache->field+cache->fields+table_count*2);

  length=0;
  for (i=0 ; i < table_count ; i++)
  {
    uint null_fields=0,used_fields;

    Field **f_ptr,*field;
    for (f_ptr=tables[i].table->field,used_fields=tables[i].used_fields ;
	 used_fields ;
	 f_ptr++)
    {
      field= *f_ptr;
      if (field->query_id == thd->query_id)
      {
	used_fields--;
	length+=field->fill_cache_field(copy);
	if (copy->blob_field)
	  (*blob_ptr++)=copy;
	if (field->maybe_null())
	  null_fields++;
	copy++;
      }
    }
    /* Copy null bits from table */
    if (null_fields && tables[i].table->null_fields)
    {						/* must copy null bits */
      copy->str=(char*) tables[i].table->null_flags;
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      copy->length=tables[i].table->null_bytes;
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      copy->strip=0;
      copy->blob_field=0;
      length+=copy->length;
      copy++;
      cache->fields++;
    }
    /* If outer join table, copy null_row flag */
    if (tables[i].table->maybe_null)
    {
      copy->str= (char*) &tables[i].table->null_row;
      copy->length=sizeof(tables[i].table->null_row);
      copy->strip=0;
      copy->blob_field=0;
      length+=copy->length;
      copy++;
      cache->fields++;
    }
  }

  cache->records=0; cache->ptr_record= (uint) ~0;
  cache->length=length+blobs*sizeof(char*);
  cache->blobs=blobs;
  *blob_ptr=0;					/* End sequentel */
6301
  size=max(thd->variables.join_buff_size, cache->length);
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  if (!(cache->buff=(uchar*) my_malloc(size,MYF(0))))
    DBUG_RETURN(1);				/* Don't use cache */ /* purecov: inspected */
  cache->end=cache->buff+size;
  reset_cache(cache);
  DBUG_RETURN(0);
}


static ulong
used_blob_length(CACHE_FIELD **ptr)
{
  uint length,blob_length;
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  DBUG_ENTER("used_blob_length");

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  for (length=0 ; *ptr ; ptr++)
  {
    (*ptr)->blob_length=blob_length=(*ptr)->blob_field->get_length();
    length+=blob_length;
    (*ptr)->blob_field->get_ptr(&(*ptr)->str);
  }
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  DBUG_RETURN(length);
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}


static bool
store_record_in_cache(JOIN_CACHE *cache)
{
  ulong length;
  uchar *pos;
  CACHE_FIELD *copy,*end_field;
  bool last_record;
6333
  DBUG_ENTER("store_record_in_cache");
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  pos=cache->pos;
  end_field=cache->field+cache->fields;

  length=cache->length;
  if (cache->blobs)
    length+=used_blob_length(cache->blob_ptr);
  if ((last_record=(length+cache->length > (uint) (cache->end - pos))))
    cache->ptr_record=cache->records;

  /*
6345
    There is room in cache. Put record there
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  */
  cache->records++;
  for (copy=cache->field ; copy < end_field; copy++)
  {
    if (copy->blob_field)
    {
      if (last_record)
      {
	copy->blob_field->get_image((char*) pos,copy->length+sizeof(char*));
	pos+=copy->length+sizeof(char*);
      }
      else
      {
	copy->blob_field->get_image((char*) pos,copy->length); // blob length
	memcpy(pos+copy->length,copy->str,copy->blob_length);  // Blob data
	pos+=copy->length+copy->blob_length;
      }
    }
    else
    {
      if (copy->strip)
      {
	char *str,*end;
	for (str=copy->str,end= str+copy->length;
	     end > str && end[-1] == ' ' ;
	     end--) ;
	length=(uint) (end-str);
	memcpy(pos+1,str,length);
	*pos=(uchar) length;
	pos+=length+1;
      }
      else
      {
	memcpy(pos,copy->str,copy->length);
	pos+=copy->length;
      }
    }
  }
  cache->pos=pos;
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  DBUG_RETURN(last_record || (uint) (cache->end -pos) < cache->length);
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}


static void
reset_cache(JOIN_CACHE *cache)
{
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  DBUG_ENTER("reset_cache");

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  cache->record_nr=0;
  cache->pos=cache->buff;
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  DBUG_VOID_RETURN;
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}


static void
read_cached_record(JOIN_TAB *tab)
{
  uchar *pos;
  uint length;
  bool last_record;
  CACHE_FIELD *copy,*end_field;
6407
  DBUG_ENTER("read_cached_record");
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  last_record=tab->cache.record_nr++ == tab->cache.ptr_record;
  pos=tab->cache.pos;

  for (copy=tab->cache.field,end_field=copy+tab->cache.fields ;
       copy < end_field;
       copy++)
  {
    if (copy->blob_field)
    {
      if (last_record)
      {
	copy->blob_field->set_image((char*) pos,copy->length+sizeof(char*));
	pos+=copy->length+sizeof(char*);
      }
      else
      {
	copy->blob_field->set_ptr((char*) pos,(char*) pos+copy->length);
	pos+=copy->length+copy->blob_field->get_length();
      }
    }
    else
    {
      if (copy->strip)
      {
	memcpy(copy->str,pos+1,length=(uint) *pos);
	memset(copy->str+length,' ',copy->length-length);
	pos+=1+length;
      }
      else
      {
	memcpy(copy->str,pos,copy->length);
	pos+=copy->length;
      }
    }
  }
  tab->cache.pos=pos;
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  DBUG_VOID_RETURN;
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}


static bool
cmp_buffer_with_ref(JOIN_TAB *tab)
{
  bool diff;
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  DBUG_ENTER("cmp_buffer_with_ref");

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  if (!(diff=tab->ref.key_err))
  {
    memcpy(tab->ref.key_buff2, tab->ref.key_buff, tab->ref.key_length);
  }
  if ((tab->ref.key_err=cp_buffer_from_ref(&tab->ref)) || diff)
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    DBUG_RETURN(1);
  DBUG_RETURN(memcmp(tab->ref.key_buff2, tab->ref.key_buff, tab->ref.key_length)
    != 0);
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}


bool
cp_buffer_from_ref(TABLE_REF *ref)
{
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  DBUG_ENTER("cp_buffer_from_ref");

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  for (store_key **copy=ref->key_copy ; *copy ; copy++)
    if ((*copy)->copy())
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      DBUG_RETURN(1);					// Something went wrong
  DBUG_RETURN(0);
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}


/*****************************************************************************
6479
  Group and order functions
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*****************************************************************************/

/*
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  Find order/group item in requested columns and change the item to point at
  it. If item doesn't exists, add it first in the field list
  Return 0 if ok.
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*/

static int
find_order_in_list(THD *thd,TABLE_LIST *tables,ORDER *order,List<Item> &fields,
		   List<Item> &all_fields)
{
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  DBUG_ENTER("find_order_in_list");

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  if ((*order->item)->type() == Item::INT_ITEM)
  {						/* Order by position */
    Item *item=0;
    List_iterator<Item> li(fields);

    for (uint count= (uint) ((Item_int*) (*order->item))->value ;
	 count-- && (item=li++) ;) ;
    if (!item)
    {
      my_printf_error(ER_BAD_FIELD_ERROR,ER(ER_BAD_FIELD_ERROR),
		      MYF(0),(*order->item)->full_name(),
	       thd->where);
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      DBUG_RETURN(1);
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    }
    order->item=li.ref();
    order->in_field_list=1;
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    DBUG_RETURN(0);
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  }
  const char *save_where=thd->where;
  thd->where=0;					// No error if not found
  Item **item=find_item_in_list(*order->item,fields);
  thd->where=save_where;
  if (item)
  {
    order->item=item;				// use it
    order->in_field_list=1;
6520
    DBUG_RETURN(0);
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  }
  order->in_field_list=0;
  if ((*order->item)->fix_fields(thd,tables) || thd->fatal_error)
6524
    DBUG_RETURN(1);					// Wrong field
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  all_fields.push_front(*order->item);		// Add new field to field list
  order->item=(Item**) all_fields.head_ref();
6527
  DBUG_RETURN(0);
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}


/*
6532 6533
  Change order to point at item in select list. If item isn't a number
  and doesn't exits in the select list, add it the the field list.
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*/

6536
int setup_order(THD *thd,TABLE_LIST *tables,List<Item> &fields,
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	     List<Item> &all_fields, ORDER *order)
{
6539 6540
  DBUG_ENTER("setup_order");

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  thd->where="order clause";
  for (; order; order=order->next)
  {
    if (find_order_in_list(thd,tables,order,fields,all_fields))
6545
      DBUG_RETURN(1);
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6546
  }
6547
  DBUG_RETURN(0);
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}


static int
setup_group(THD *thd,TABLE_LIST *tables,List<Item> &fields,
	    List<Item> &all_fields, ORDER *order, bool *hidden_group_fields)
{
6555 6556
  DBUG_ENTER("setup_group");

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6557 6558
  *hidden_group_fields=0;
  if (!order)
6559
    DBUG_RETURN(0);				/* Everything is ok */
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6560

6561
  if (thd->sql_mode & MODE_ONLY_FULL_GROUP_BY)
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  {
    Item *item;
    List_iterator<Item> li(fields);
    while ((item=li++))
      item->marker=0;			/* Marker that field is not used */
  }
  uint org_fields=all_fields.elements;

  thd->where="group statement";
6571
  for (; order; order=order->next)
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  {
    if (find_order_in_list(thd,tables,order,fields,all_fields))
6574
      DBUG_RETURN(1);
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    (*order->item)->marker=1;		/* Mark found */
    if ((*order->item)->with_sum_func)
    {
      my_printf_error(ER_WRONG_GROUP_FIELD, ER(ER_WRONG_GROUP_FIELD),MYF(0),
		      (*order->item)->full_name());
6580
      DBUG_RETURN(1);
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    }
  }
6583
  if (thd->sql_mode & MODE_ONLY_FULL_GROUP_BY)
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  {
    /* Don't allow one to use fields that is not used in GROUP BY */
    Item *item;
    List_iterator<Item> li(fields);

    while ((item=li++))
    {
      if (item->type() != Item::SUM_FUNC_ITEM && !item->marker)
      {
	my_printf_error(ER_WRONG_FIELD_WITH_GROUP,
			ER(ER_WRONG_FIELD_WITH_GROUP),
			MYF(0),item->full_name());
6596
	DBUG_RETURN(1);
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      }
    }
  }
  if (org_fields != all_fields.elements)
    *hidden_group_fields=1;			// group fields is not used
6602
  DBUG_RETURN(0);
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}

/*
6606
  Add fields with aren't used at start of field list. Return FALSE if ok
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*/

static bool
setup_new_fields(THD *thd,TABLE_LIST *tables,List<Item> &fields,
		 List<Item> &all_fields, ORDER *new_field)
{
  Item	  **item;
  DBUG_ENTER("setup_new_fields");

  thd->set_query_id=1;				// Not really needed, but...
  thd->where=0;					// Don't give error
6618
  for (; new_field ; new_field=new_field->next)
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  {
    if ((item=find_item_in_list(*new_field->item,fields)))
      new_field->item=item;			/* Change to shared Item */
    else
    {
      thd->where="procedure list";
      if ((*new_field->item)->fix_fields(thd,tables))
	DBUG_RETURN(1); /* purecov: inspected */
      thd->where=0;
      all_fields.push_front(*new_field->item);
      new_field->item=all_fields.head_ref();
    }
  }
  DBUG_RETURN(0);
}

/*
6636 6637 6638
  Create a group by that consist of all non const fields. Try to use
  the fields in the order given by 'order' to allow one to optimize
  away 'order by'.
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*/

static ORDER *
create_distinct_group(ORDER *order_list,List<Item> &fields)
{
  List_iterator<Item> li(fields);
  Item *item;
  ORDER *order,*group,**prev;
6647
  DBUG_ENTER("create_distinct_group");
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  while ((item=li++))
    item->marker=0;			/* Marker that field is not used */

  prev= &group;  group=0;
  for (order=order_list ; order; order=order->next)
  {
    if (order->in_field_list)
    {
      ORDER *ord=(ORDER*) sql_memdup(order,sizeof(ORDER));
      if (!ord)
6659
	DBUG_RETURN(0);
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      *prev=ord;
      prev= &ord->next;
      (*ord->item)->marker=1;
    }
  }

  li.rewind();
  while ((item=li++))
  {
    if (item->const_item() || item->with_sum_func)
      continue;
    if (!item->marker)
    {
      ORDER *ord=(ORDER*) sql_calloc(sizeof(ORDER));
      if (!ord)
6675
	DBUG_RETURN(0);
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      ord->item=li.ref();
      ord->asc=1;
      *prev=ord;
      prev= &ord->next;
    }
  }
  *prev=0;
6683
  DBUG_RETURN(group);
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}


/*****************************************************************************
6688
  Update join with count of the different type of fields
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*****************************************************************************/

void
6692 6693
count_field_types(TMP_TABLE_PARAM *param, List<Item> &fields,
		  bool reset_with_sum_func)
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{
  List_iterator<Item> li(fields);
  Item *field;
6697
  DBUG_ENTER("count_field_types");
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6698

6699
  param->field_count=param->sum_func_count=param->func_count=
6700
    param->hidden_field_count=0;
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  param->quick_group=1;
  while ((field=li++))
  {
    Item::Type type=field->type();
    if (type == Item::FIELD_ITEM)
      param->field_count++;
    else if (type == Item::SUM_FUNC_ITEM)
    {
      if (! field->const_item())
      {
	Item_sum *sum_item=(Item_sum*) field;
	if (!sum_item->quick_group)
	  param->quick_group=0;			// UDF SUM function
	param->sum_func_count++;

	for (uint i=0 ; i < sum_item->arg_count ; i++)
	{
	  if (sum_item->args[0]->type() == Item::FIELD_ITEM)
	    param->field_count++;
	  else
	    param->func_count++;
	}
      }
    }
    else
6726
    {
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6727
      param->func_count++;
6728 6729 6730
      if (reset_with_sum_func)
	field->with_sum_func=0;
    }
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6731
  }
6732
  DBUG_VOID_RETURN;
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}


/*
  Return 1 if second is a subpart of first argument
  If first parts has different direction, change it to second part
  (group is sorted like order)
*/

static bool
test_if_subpart(ORDER *a,ORDER *b)
{
6745 6746
  DBUG_ENTER("test_if_subpart");

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  for (; a && b; a=a->next,b=b->next)
  {
6749
    if ((*a->item)->eq(*b->item,1))
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      a->asc=b->asc;
    else
6752
      DBUG_RETURN(0);
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6753
  }
6754
  DBUG_RETURN(test(!b));
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}

/*
  Return table number if there is only one table in sort order
  and group and order is compatible
  else return 0;
*/

static TABLE *
get_sort_by_table(ORDER *a,ORDER *b,TABLE_LIST *tables)
{
  table_map map= (table_map) 0;
  DBUG_ENTER("get_sort_by_table");

  if (!a)
    a=b;					// Only one need to be given
  else if (!b)
    b=a;

  for (; a && b; a=a->next,b=b->next)
  {
6776
    if (!(*a->item)->eq(*b->item,1))
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      DBUG_RETURN(0);
    map|=a->item[0]->used_tables();
  }
  if (!map || (map & RAND_TABLE_BIT))
    DBUG_RETURN(0);

6783
  for (; !(map & tables->table->map) ; tables=tables->next) ;
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  if (map != tables->table->map)
    DBUG_RETURN(0);				// More than one table
  DBUG_PRINT("exit",("sort by table: %d",tables->table->tablenr));
  DBUG_RETURN(tables->table);
}


	/* calc how big buffer we need for comparing group entries */

static void
calc_group_buffer(JOIN *join,ORDER *group)
{
6796
  uint key_length=0, parts=0, null_parts=0;
6797
  DBUG_ENTER("calc_group_buffer");
6798

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  if (group)
    join->group= 1;
  for (; group ; group=group->next)
  {
    Field *field=(*group->item)->tmp_table_field();
    if (field)
    {
      if (field->type() == FIELD_TYPE_BLOB)
	key_length+=MAX_BLOB_WIDTH;		// Can't be used as a key
      else
	key_length+=field->pack_length();
    }
    else if ((*group->item)->result_type() == REAL_RESULT)
      key_length+=sizeof(double);
    else if ((*group->item)->result_type() == INT_RESULT)
      key_length+=sizeof(longlong);
    else
      key_length+=(*group->item)->max_length;
    parts++;
    if ((*group->item)->maybe_null)
6819
      null_parts++;
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6820
  }
6821
  join->tmp_table_param.group_length=key_length+null_parts;
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6822
  join->tmp_table_param.group_parts=parts;
6823
  join->tmp_table_param.group_null_parts=null_parts;
6824
  DBUG_VOID_RETURN;
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}


/*
6829 6830
  Get a list of buffers for saveing last group
  Groups are saved in reverse order for easyer check loop
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6831 6832 6833 6834 6835
*/

static bool
alloc_group_fields(JOIN *join,ORDER *group)
{
6836 6837
  DBUG_ENTER("alloc_group_fields");

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  if (group)
  {
    for (; group ; group=group->next)
    {
      Item_buff *tmp=new_Item_buff(*group->item);
      if (!tmp || join->group_fields.push_front(tmp))
6844
	DBUG_RETURN(TRUE);
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    }
  }
  join->sort_and_group=1;			/* Mark for do_select */
6848
  DBUG_RETURN(FALSE);
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}


static int
test_if_group_changed(List<Item_buff> &list)
{
  List_iterator<Item_buff> li(list);
  int idx= -1,i;
  Item_buff *buff;
6858
  DBUG_ENTER("test_if_group_changed");
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  for (i=(int) list.elements-1 ; (buff=li++) ; i--)
  {
    if (buff->cmp())
      idx=i;
  }
6865
  DBUG_RETURN(idx);
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}



/*
6871 6872 6873 6874
  Setup copy_fields to save fields at start of new group
  Only FIELD_ITEM:s and FUNC_ITEM:s needs to be saved between groups.
  Change old item_field to use a new field with points at saved fieldvalue
  This function is only called before use of send_fields
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*/

bool
6878
setup_copy_fields(THD *thd, TMP_TABLE_PARAM *param, List<Item> &fields)
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{
  Item *pos;
  List_iterator<Item> li(fields);
  Copy_field *copy;
  DBUG_ENTER("setup_copy_fields");

  if (!(copy=param->copy_field= new Copy_field[param->field_count]))
6886
    goto err2;
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  param->copy_funcs.empty();
  while ((pos=li++))
  {
    if (pos->type() == Item::FIELD_ITEM)
    {
      Item_field *item=(Item_field*) pos;
      if (item->field->flags & BLOB_FLAG)
      {
	if (!(pos=new Item_copy_string(pos)))
	  goto err;
	VOID(li.replace(pos));
	if (param->copy_funcs.push_back(pos))
	  goto err;
	continue;
      }

      /* set up save buffer and change result_field to point at saved value */
      Field *field= item->field;
6906
      item->result_field=field->new_field(&thd->mem_root,field->table);
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      char *tmp=(char*) sql_alloc(field->pack_length()+1);
      if (!tmp)
	goto err;
      copy->set(tmp, item->result_field);
      item->result_field->move_field(copy->to_ptr,copy->to_null_ptr,1);
      copy++;
    }
    else if ((pos->type() == Item::FUNC_ITEM ||
	      pos->type() == Item::COND_ITEM) &&
	     !pos->with_sum_func)
    {						// Save for send fields
      /* TODO:
	 In most cases this result will be sent to the user.
	 This should be changed to use copy_int or copy_real depending
	 on how the value is to be used: In some cases this may be an
	 argument in a group function, like: IF(ISNULL(col),0,COUNT(*))
      */
      if (!(pos=new Item_copy_string(pos)))
	goto err;
      VOID(li.replace(pos));
      if (param->copy_funcs.push_back(pos))
	goto err;
    }
  }
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  param->copy_field_end= copy;
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  DBUG_RETURN(0);

 err:
6935
  delete [] param->copy_field;			// This is never 0
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6936
  param->copy_field=0;
6937
err2:
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  DBUG_RETURN(TRUE);
}


/*
6943
  Copy fields and null values between two tables
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*/

void
copy_fields(TMP_TABLE_PARAM *param)
{
  Copy_field *ptr=param->copy_field;
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6950
  Copy_field *end=param->copy_field_end;
6951
  DBUG_ENTER("copy_fields");
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6953
  for (; ptr != end; ptr++)
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    (*ptr->do_copy)(ptr);

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  List_iterator_fast<Item> &it=param->copy_funcs_it;
  it.rewind();
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  Item_copy_string *item;
  while ((item = (Item_copy_string*) it++))
    item->copy();
6961
  DBUG_VOID_RETURN;
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}


/*****************************************************************************
6966
  Make an array of pointer to sum_functions to speed up sum_func calculation
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*****************************************************************************/

static bool
make_sum_func_list(JOIN *join,List<Item> &fields)
{
  DBUG_ENTER("make_sum_func_list");
  Item_sum **func =
    (Item_sum**) sql_alloc(sizeof(Item_sum*)*
			   (join->tmp_table_param.sum_func_count+1));
  if (!func)
    DBUG_RETURN(TRUE);
  List_iterator<Item> it(fields);
  join->sum_funcs=func;

  Item *field;
  while ((field=it++))
  {
    if (field->type() == Item::SUM_FUNC_ITEM && !field->const_item())
    {
      *func++=(Item_sum*) field;
      /* let COUNT(DISTINCT) create the temporary table */
      if (((Item_sum*) field)->setup(join->thd))
	DBUG_RETURN(TRUE);
    }
  }
  *func=0;					// End marker
  DBUG_RETURN(FALSE);
}


/*
6998
  Change all funcs and sum_funcs to fields in tmp table
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*/

static bool
7002
change_to_use_tmp_fields(List<Item> &items)
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{
  List_iterator<Item> it(items);
  Item *item_field,*item;
7006
  DBUG_ENTER("change_to_use_tmp_fields");
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  while ((item=it++))
  {
    Field *field;
    if (item->with_sum_func && item->type() != Item::SUM_FUNC_ITEM)
      continue;
    if (item->type() == Item::FIELD_ITEM)
    {
      ((Item_field*) item)->field=
	((Item_field*) item)->result_field;
    }
    else if ((field=item->tmp_table_field()))
    {
      if (item->type() == Item::SUM_FUNC_ITEM && field->table->group)
	item_field=((Item_sum*) item)->result_item(field);
      else
	item_field=(Item*) new Item_field(field);
      if (!item_field)
7025
	DBUG_RETURN(TRUE);				// Fatal error
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      item_field->name=item->name;		/*lint -e613 */
#ifndef DBUG_OFF
      if (_db_on_ && !item_field->name)
      {
	char buff[256];
	String str(buff,sizeof(buff));
	str.length(0);
	item->print(&str);
	item_field->name=sql_strmake(str.ptr(),str.length());
      }
#endif
#ifdef DELETE_ITEMS
      delete it.replace(item_field);		/*lint -e613 */
#else
      (void) it.replace(item_field);		/*lint -e613 */
#endif
    }
  }
7044
  DBUG_RETURN(FALSE);
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}


/*
7049 7050
  Change all sum_func refs to fields to point at fields in tmp table
  Change all funcs to be fields in tmp table
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*/

static bool
change_refs_to_tmp_fields(THD *thd,List<Item> &items)
{
  List_iterator<Item> it(items);
  Item *item;
7058
  DBUG_ENTER("change_refs_to_tmp_fields");
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  while ((item= it++))
  {
    if (item->type() == Item::SUM_FUNC_ITEM)
    {
      if (!item->const_item())
      {
	Item_sum *sum_item= (Item_sum*) item;
	if (sum_item->result_field)		// If not a const sum func
	{
	  Field *result_field=sum_item->result_field;
	  for (uint i=0 ; i < sum_item->arg_count ; i++)
	  {
	    Item *arg= sum_item->args[i];
	    if (!arg->const_item())
	    {
	      if (arg->type() == Item::FIELD_ITEM)
		((Item_field*) arg)->field= result_field++;
	      else
		sum_item->args[i]= new Item_field(result_field++);
	    }
	  }
	}
      }
    }
    else if (item->with_sum_func)
      continue;
    else if ((item->type() == Item::FUNC_ITEM ||
	      item->type() == Item::COND_ITEM) &&
	     !item->const_item())
    {						/* All funcs are stored */
#ifdef DELETE_ITEMS
      delete it.replace(new Item_field(((Item_func*) item)->result_field));
#else
      (void) it.replace(new Item_field(((Item_func*) item)->result_field));
#endif
    }
    else if (item->type() == Item::FIELD_ITEM)	/* Change refs */
    {
      ((Item_field*)item)->field=((Item_field*) item)->result_field;
    }
  }
7101
  DBUG_RETURN(thd->fatal_error);
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}



/******************************************************************************
7107
  Code for calculating functions
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******************************************************************************/

static void
init_tmptable_sum_functions(Item_sum **func_ptr)
{
  Item_sum *func;
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  DBUG_ENTER("init_tmptable_sum_functions");

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  while ((func= *(func_ptr++)))
    func->reset_field();
7118
  DBUG_VOID_RETURN;
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}


	/* Update record 0 in tmp_table from record 1 */

static void
update_tmptable_sum_func(Item_sum **func_ptr,
			 TABLE *tmp_table __attribute__((unused)))
{
  Item_sum *func;
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  DBUG_ENTER("update_tmptable_sum_func");

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  while ((func= *(func_ptr++)))
    func->update_field(0);
7133
  DBUG_VOID_RETURN;
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}


	/* Copy result of sum functions to record in tmp_table */

static void
copy_sum_funcs(Item_sum **func_ptr)
{
  Item_sum *func;
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  DBUG_ENTER("copy_sum_funcs");

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  for (; (func = *func_ptr) ; func_ptr++)
    (void) func->save_in_field(func->result_field);
7147
  DBUG_VOID_RETURN;
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}


static void
init_sum_functions(Item_sum **func_ptr)
{
  Item_sum *func;
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  DBUG_ENTER("init_sum_functions");

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  for (; (func= (Item_sum*) *func_ptr) ; func_ptr++)
    func->reset();
7159
  DBUG_VOID_RETURN;
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}


static bool
update_sum_func(Item_sum **func_ptr)
{
  Item_sum *func;
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  DBUG_ENTER("update_sum_func");

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  for (; (func= (Item_sum*) *func_ptr) ; func_ptr++)
    if (func->add())
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      DBUG_RETURN(1);
  DBUG_RETURN(0);
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}

	/* Copy result of functions to record in tmp_table */

void
copy_funcs(Item_result_field **func_ptr)
{
  Item_result_field *func;
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  DBUG_ENTER("copy_funcs");

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  for (; (func = *func_ptr) ; func_ptr++)
    (void) func->save_in_field(func->result_field);
7185
  DBUG_VOID_RETURN;
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}


/*****************************************************************************
7190 7191
  Create a condition for a const reference and add this to the
  currenct select for the table
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*****************************************************************************/

static bool add_ref_to_table_cond(THD *thd, JOIN_TAB *join_tab)
{
  DBUG_ENTER("add_ref_to_table_cond");
  if (!join_tab->ref.key_parts)
    DBUG_RETURN(FALSE);

  Item_cond_and *cond=new Item_cond_and();
  TABLE *table=join_tab->table;
  int error;
  if (!cond)
    DBUG_RETURN(TRUE);

  for (uint i=0 ; i < join_tab->ref.key_parts ; i++)
  {
    Field *field=table->field[table->key_info[join_tab->ref.key].key_part[i].fieldnr-1];
    Item *value=join_tab->ref.items[i];
    cond->add(new Item_func_equal(new Item_field(field),value));
  }
  if (thd->fatal_error)
    DBUG_RETURN(TRUE);
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  /*
    Here we pass 0 as the first argument to fix_fields that don't need
    to do any stack checking (This is already done in the initial fix_fields).
  */
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  cond->fix_fields((THD *) 0,(TABLE_LIST *) 0);
  if (join_tab->select)
  {
    error=(int) cond->add(join_tab->select->cond);
    join_tab->select_cond=join_tab->select->cond=cond;
  }
  else if ((join_tab->select=make_select(join_tab->table, 0, 0, cond,&error)))
    join_tab->select_cond=cond;

  DBUG_RETURN(error ? TRUE : FALSE);
}

/****************************************************************************
7232
  Send a description about what how the select will be done to stdout
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****************************************************************************/

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7235
static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
7236
			    bool distinct,const char *message)
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{
  List<Item> field_list;
  Item *item;
7240
  List<Item> item_list;
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  THD *thd=join->thd;
7242
  MYSQL_LOCK *save_lock;
7243
  SELECT_LEX *select_lex = &(join->thd->lex.select_lex);
7244
  select_result *result=join->result;
7245
  Item *item_null= new Item_null();
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7246
  DBUG_ENTER("select_describe");
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7248
  /* Don't log this into the slow query log */
7249
  select_lex->options&= ~(QUERY_NO_INDEX_USED | QUERY_NO_GOOD_INDEX_USED);
7250
  thd->offset_limit=0;
7251
  if (thd->lex.select == select_lex)
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  {
    field_list.push_back(new Item_empty_string("table",NAME_LEN));
    field_list.push_back(new Item_empty_string("type",10));
    field_list.push_back(item=new Item_empty_string("possible_keys",
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						  NAME_LEN*MAX_KEY));
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    item->maybe_null=1;
    field_list.push_back(item=new Item_empty_string("key",NAME_LEN));
    item->maybe_null=1;
    field_list.push_back(item=new Item_int("key_len",0,3));
    item->maybe_null=1;
    field_list.push_back(item=new Item_empty_string("ref",
						    NAME_LEN*MAX_REF_PARTS));
    item->maybe_null=1;
    field_list.push_back(new Item_real("rows",0.0,0,10));
    field_list.push_back(new Item_empty_string("Extra",255));
7267
    if (result->send_fields(field_list,1))
7268
      DBUG_VOID_RETURN;
7269
  }
7270

7271
  if (message)
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  {
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    Item *empty= new Item_empty_string("",0);
    for (uint i=0 ; i < 7; i++)
      item_list.push_back(empty);
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    item_list.push_back(new Item_string(message,strlen(message)));
    if (result->send_data(item_list))
      result->send_error(0,NullS);
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  }
  else
  {
    table_map used_tables=0;
    for (uint i=0 ; i < join->tables ; i++)
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    {
7285 7286
      JOIN_TAB *tab=join->join_tab+i;
      TABLE *table=tab->table;
7287
      char buff[512],*buff_ptr=buff;
7288
      char buff1[512], buff2[512], buff3[512];
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      String tmp1(buff1,sizeof(buff1));
      String tmp2(buff2,sizeof(buff2));
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      tmp1.length(0);
      tmp2.length(0);
7293
      item_list.empty();
7294

7295 7296
      if (tab->type == JT_ALL && tab->select && tab->select->quick)
	tab->type= JT_RANGE;
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      item_list.push_back(new Item_string(table->table_name,
					  strlen(table->table_name)));
      item_list.push_back(new Item_string(join_type_str[tab->type],
					  strlen(join_type_str[tab->type])));
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      key_map bits;
      uint j;
      for (j=0,bits=tab->keys ; bits ; j++,bits>>=1)
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      {
7305 7306
	if (bits & 1)
	{
7307 7308 7309
	  if (tmp1.length())
	    tmp1.append(',');
	  tmp1.append(table->key_info[j].name);
7310
	}
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      }
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      if (tmp1.length())
	item_list.push_back(new Item_string(tmp1.ptr(),tmp1.length()));
7314
      else
7315
	item_list.push_back(item_null);
7316
      if (tab->ref.key_parts)
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      {
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	KEY *key_info=table->key_info+ tab->ref.key;
	item_list.push_back(new Item_string(key_info->name,
					    strlen(key_info->name)));
7321
	item_list.push_back(new Item_int((int32) tab->ref.key_length));
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	for (store_key **ref=tab->ref.key_copy ; *ref ; ref++)
	{
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	  if (tmp2.length())
	    tmp2.append(',');
	  tmp2.append((*ref)->name());
7327
	}
7328
	item_list.push_back(new Item_string(tmp2.ptr(),tmp2.length()));
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      }
      else if (tab->type == JT_NEXT)
      {
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	KEY *key_info=table->key_info+ tab->index;
	item_list.push_back(new Item_string(key_info->name,
					    strlen(key_info->name)));
	item_list.push_back(new Item_int((int32) key_info->key_length));
	item_list.push_back(item_null);
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      }
      else if (tab->select && tab->select->quick)
      {
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	KEY *key_info=table->key_info+ tab->select->quick->index;
	item_list.push_back(new Item_string(key_info->name,
					    strlen(key_info->name)));
7343
	item_list.push_back(new Item_int((int32) tab->select->quick->max_used_key_length));
7344
	item_list.push_back(item_null);
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      }
      else
      {
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	item_list.push_back(item_null);
	item_list.push_back(item_null);
	item_list.push_back(item_null);
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      }
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      sprintf(buff3,"%.0f",join->best_positions[i].records_read);
      item_list.push_back(new Item_string(buff3,strlen(buff3)));
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      my_bool key_read=table->key_read;
      if (tab->type == JT_NEXT &&
	  ((table->used_keys & ((key_map) 1 << tab->index))))
	key_read=1;
      
      if (tab->info)
7360
	item_list.push_back(new Item_string(tab->info,strlen(tab->info)));
7361
      else if (tab->select)
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      {
7363 7364
	if (tab->use_quick == 2)
	{
7365
	  sprintf(buff_ptr,"; Range checked for each record (index map: %u)",
7366 7367 7368 7369
		  tab->keys);
	  buff_ptr=strend(buff_ptr);
	}
	else
7370
	  buff_ptr=strmov(buff_ptr,"; Using where");
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      }
7372
      if (key_read)
7373
	buff_ptr= strmov(buff_ptr,"; Using index");
7374
      if (table->reginfo.not_exists_optimize)
7375
	buff_ptr= strmov(buff_ptr,"; Not exists");
7376
      if (need_tmp_table)
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      {
7378
	need_tmp_table=0;
7379
	buff_ptr= strmov(buff_ptr,"; Using temporary");
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      }
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      if (need_order)
      {
	need_order=0;
7384
	buff_ptr= strmov(buff_ptr,"; Using filesort");
7385
      }
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      if (distinct && test_all_bits(used_tables,thd->used_tables))
	buff_ptr= strmov(buff_ptr,"; Distinct");
      if (buff_ptr == buff)
	buff_ptr+= 2;
      item_list.push_back(new Item_string(buff+2,(uint) (buff_ptr - buff)-2));
7391 7392
      // For next iteration
      used_tables|=table->map;
7393 7394
      if (result->send_data(item_list))
	result->send_error(0,NullS);
7395
    }
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  }
7397
  if (!thd->lex.select->next)			// Not union
7398 7399 7400 7401 7402 7403
  {
    save_lock=thd->lock;
    thd->lock=(MYSQL_LOCK *)0;
    result->send_eof();
    thd->lock=save_lock;
  }
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  DBUG_VOID_RETURN;
}


7408
static void describe_info(JOIN *join, const char *info)
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7409
{
7410
  THD *thd= join->thd;
7411
  DBUG_ENTER("describe_info");
7412 7413 7414 7415

  if (thd->lex.select_lex.next)			/* If in UNION */
  {
    select_describe(join,FALSE,FALSE,FALSE,info);
7416
    DBUG_VOID_RETURN;
7417
  }
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  List<Item> field_list;
  String *packet= &thd->packet;

7421
  /* Don't log this into the slow query log */
7422 7423
  thd->lex.select_lex.options&= ~(QUERY_NO_INDEX_USED |
				  QUERY_NO_GOOD_INDEX_USED);
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  field_list.push_back(new Item_empty_string("Comment",80));
  if (send_fields(thd,field_list,1))
7426
    DBUG_VOID_RETURN; /* purecov: inspected */
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  packet->length(0);
  net_store_data(packet,info);
  if (!my_net_write(&thd->net,(char*) packet->ptr(),packet->length()))
    send_eof(&thd->net);
7431
  DBUG_VOID_RETURN;
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}