table.cc

/*
   Copyright (c) 2000, 2011, Oracle and/or its affiliates.
   Copyright (c) 2008, 2013, Monty Program 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; version 2 of the License.

   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 */


/* Some general useful functions */

#include "my_global.h"                          /* NO_EMBEDDED_ACCESS_CHECKS */
#include "sql_priv.h"
#include "unireg.h"                    // REQUIRED: for other includes
#include "table.h"
#include "key.h"                                // find_ref_key
#include "sql_table.h"                          // build_table_filename,
                                                // primary_key_name
#include "sql_trigger.h"
#include "sql_parse.h"                          // free_items
#include "strfunc.h"                            // unhex_type2
#include "sql_partition.h"       // mysql_unpack_partition,
                                 // fix_partition_func, partition_info
#include "sql_acl.h"             // *_ACL, acl_getroot_no_password
#include "sql_base.h"            // release_table_share
#include "create_options.h"
#include <m_ctype.h>
#include "my_md5.h"
#include "my_bit.h"
#include "sql_select.h"
#include "sql_derived.h"
#include "sql_statistics.h"
#include "discover.h"
#include "mdl.h"                 // MDL_wait_for_graph_visitor

/* INFORMATION_SCHEMA name */
LEX_STRING INFORMATION_SCHEMA_NAME= {C_STRING_WITH_LEN("information_schema")};

/* PERFORMANCE_SCHEMA name */
LEX_STRING PERFORMANCE_SCHEMA_DB_NAME= {C_STRING_WITH_LEN("performance_schema")};

/* MYSQL_SCHEMA name */
LEX_STRING MYSQL_SCHEMA_NAME= {C_STRING_WITH_LEN("mysql")};

/* GENERAL_LOG name */
LEX_STRING GENERAL_LOG_NAME= {C_STRING_WITH_LEN("general_log")};

/* SLOW_LOG name */
LEX_STRING SLOW_LOG_NAME= {C_STRING_WITH_LEN("slow_log")};

/* 
  Keyword added as a prefix when parsing the defining expression for a
  virtual column read from the column definition saved in the frm file
*/
LEX_STRING parse_vcol_keyword= { C_STRING_WITH_LEN("PARSE_VCOL_EXPR ") };

	/* Functions defined in this file */

static void fix_type_pointers(const char ***array, TYPELIB *point_to_type,
			      uint types, char **names);
static uint find_field(Field **fields, uchar *record, uint start, uint length);

inline bool is_system_table_name(const char *name, uint length);

/**************************************************************************
  Object_creation_ctx implementation.
**************************************************************************/

Object_creation_ctx *Object_creation_ctx::set_n_backup(THD *thd)
{
  Object_creation_ctx *backup_ctx;
  DBUG_ENTER("Object_creation_ctx::set_n_backup");

  backup_ctx= create_backup_ctx(thd);
  change_env(thd);

  DBUG_RETURN(backup_ctx);
}

void Object_creation_ctx::restore_env(THD *thd, Object_creation_ctx *backup_ctx)
{
  if (!backup_ctx)
    return;

  backup_ctx->change_env(thd);

  delete backup_ctx;
}

/**************************************************************************
  Default_object_creation_ctx implementation.
**************************************************************************/

Default_object_creation_ctx::Default_object_creation_ctx(THD *thd)
  : m_client_cs(thd->variables.character_set_client),
    m_connection_cl(thd->variables.collation_connection)
{ }

Default_object_creation_ctx::Default_object_creation_ctx(
  CHARSET_INFO *client_cs, CHARSET_INFO *connection_cl)
  : m_client_cs(client_cs),
    m_connection_cl(connection_cl)
{ }

Object_creation_ctx *
Default_object_creation_ctx::create_backup_ctx(THD *thd) const
{
  return new Default_object_creation_ctx(thd);
}

void Default_object_creation_ctx::change_env(THD *thd) const
{
  thd->variables.character_set_client= m_client_cs;
  thd->variables.collation_connection= m_connection_cl;

  thd->update_charset();
}

/**************************************************************************
  View_creation_ctx implementation.
**************************************************************************/

View_creation_ctx *View_creation_ctx::create(THD *thd)
{
  View_creation_ctx *ctx= new (thd->mem_root) View_creation_ctx(thd);

  return ctx;
}

/*************************************************************************/

View_creation_ctx * View_creation_ctx::create(THD *thd,
                                              TABLE_LIST *view)
{
  View_creation_ctx *ctx= new (thd->mem_root) View_creation_ctx(thd);

  /* Throw a warning if there is NULL cs name. */

  if (!view->view_client_cs_name.str ||
      !view->view_connection_cl_name.str)
  {
    push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
                        ER_VIEW_NO_CREATION_CTX,
                        ER(ER_VIEW_NO_CREATION_CTX),
                        (const char *) view->db,
                        (const char *) view->table_name);

    ctx->m_client_cs= system_charset_info;
    ctx->m_connection_cl= system_charset_info;

    return ctx;
  }

  /* Resolve cs names. Throw a warning if there is unknown cs name. */

  bool invalid_creation_ctx;

  invalid_creation_ctx= resolve_charset(view->view_client_cs_name.str,
                                        system_charset_info,
                                        &ctx->m_client_cs);

  invalid_creation_ctx= resolve_collation(view->view_connection_cl_name.str,
                                          system_charset_info,
                                          &ctx->m_connection_cl) ||
                        invalid_creation_ctx;

  if (invalid_creation_ctx)
  {
    sql_print_warning("View '%s'.'%s': there is unknown charset/collation "
                      "names (client: '%s'; connection: '%s').",
                      (const char *) view->db,
                      (const char *) view->table_name,
                      (const char *) view->view_client_cs_name.str,
                      (const char *) view->view_connection_cl_name.str);

    push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
                        ER_VIEW_INVALID_CREATION_CTX,
                        ER(ER_VIEW_INVALID_CREATION_CTX),
                        (const char *) view->db,
                        (const char *) view->table_name);
  }

  return ctx;
}

/*************************************************************************/

/* Get column name from column hash */

static uchar *get_field_name(Field **buff, size_t *length,
                             my_bool not_used __attribute__((unused)))
{
  *length= (uint) strlen((*buff)->field_name);
  return (uchar*) (*buff)->field_name;
}


/*
  Returns pointer to '.frm' extension of the file name.

  SYNOPSIS
    fn_rext()
    name       file name

  DESCRIPTION
    Checks file name part starting with the rightmost '.' character,
    and returns it if it is equal to '.frm'. 

  TODO
    It is a good idea to get rid of this function modifying the code
    to garantee that the functions presently calling fn_rext() always
    get arguments in the same format: either with '.frm' or without '.frm'.

  RETURN VALUES
    Pointer to the '.frm' extension. If there is no extension,
    or extension is not '.frm', pointer at the end of file name.
*/

char *fn_rext(char *name)
{
  char *res= strrchr(name, '.');
  if (res && !strcmp(res, reg_ext))
    return res;
  return name + strlen(name);
}

TABLE_CATEGORY get_table_category(const LEX_STRING *db, const LEX_STRING *name)
{
  DBUG_ASSERT(db != NULL);
  DBUG_ASSERT(name != NULL);

  if (is_infoschema_db(db->str, db->length))
    return TABLE_CATEGORY_INFORMATION;

  if ((db->length == PERFORMANCE_SCHEMA_DB_NAME.length) &&
      (my_strcasecmp(system_charset_info,
                     PERFORMANCE_SCHEMA_DB_NAME.str,
                     db->str) == 0))
    return TABLE_CATEGORY_PERFORMANCE;

  if ((db->length == MYSQL_SCHEMA_NAME.length) &&
      (my_strcasecmp(system_charset_info,
                     MYSQL_SCHEMA_NAME.str,
                     db->str) == 0))
  {
    if (is_system_table_name(name->str, name->length))
      return TABLE_CATEGORY_SYSTEM;

    if ((name->length == GENERAL_LOG_NAME.length) &&
        (my_strcasecmp(system_charset_info,
                       GENERAL_LOG_NAME.str,
                       name->str) == 0))
      return TABLE_CATEGORY_LOG;

    if ((name->length == SLOW_LOG_NAME.length) &&
        (my_strcasecmp(system_charset_info,
                       SLOW_LOG_NAME.str,
                       name->str) == 0))
      return TABLE_CATEGORY_LOG;
  }

  return TABLE_CATEGORY_USER;
}


/*
  Allocate a setup TABLE_SHARE structure

  SYNOPSIS
    alloc_table_share()
    TABLE_LIST		Take database and table name from there
    key			Table cache key (db \0 table_name \0...)
    key_length		Length of key

  RETURN
    0  Error (out of memory)
    #  Share
*/

TABLE_SHARE *alloc_table_share(const char *db, const char *table_name,
                               char *key, uint key_length)
{
  MEM_ROOT mem_root;
  TABLE_SHARE *share;
  char *key_buff, *path_buff;
  char path[FN_REFLEN];
  uint path_length;
  DBUG_ENTER("alloc_table_share");
  DBUG_PRINT("enter", ("table: '%s'.'%s'", db, table_name));

  path_length= build_table_filename(path, sizeof(path) - 1,
                                    db, table_name, "", 0);
  init_sql_alloc(&mem_root, TABLE_ALLOC_BLOCK_SIZE, 0, MYF(0));
  if (multi_alloc_root(&mem_root,
                       &share, sizeof(*share),
                       &key_buff, key_length,
                       &path_buff, path_length + 1,
                       NULL))
  {
    bzero((char*) share, sizeof(*share));

    share->set_table_cache_key(key_buff, key, key_length);

    share->path.str= path_buff;
    share->path.length= path_length;
    strmov(share->path.str, path);
    share->normalized_path.str=    share->path.str;
    share->normalized_path.length= path_length;
    share->table_category= get_table_category(& share->db, & share->table_name);
    share->set_refresh_version();
    share->open_errno= ENOENT;

    /*
      Since alloc_table_share() can be called without any locking (for
      example, ha_create_table... functions), we do not assign a table
      map id here.  Instead we assign a value that is not used
      elsewhere, and then assign a table map id inside open_table()
      under the protection of the LOCK_open mutex.
    */
    share->table_map_id= ~0UL;
    share->cached_row_logging_check= -1;

    share->used_tables.empty();
    share->free_tables.empty();
    share->m_flush_tickets.empty();

    init_sql_alloc(&share->stats_cb.mem_root, TABLE_ALLOC_BLOCK_SIZE, 0, MYF(0));

    memcpy((char*) &share->mem_root, (char*) &mem_root, sizeof(mem_root));
    mysql_mutex_init(key_TABLE_SHARE_LOCK_ha_data,
                     &share->LOCK_ha_data, MY_MUTEX_INIT_FAST);
  }
  DBUG_RETURN(share);
}


/*
  Initialize share for temporary tables

  SYNOPSIS
    init_tmp_table_share()
    thd         thread handle
    share	Share to fill
    key		Table_cache_key, as generated from create_table_def_key.
		must start with db name.    
    key_length	Length of key
    table_name	Table name
    path	Path to file (possible in lower case) without .frm

  NOTES
    This is different from alloc_table_share() because temporary tables
    don't have to be shared between threads or put into the table def
    cache, so we can do some things notable simpler and faster

    If table is not put in thd->temporary_tables (happens only when
    one uses OPEN TEMPORARY) then one can specify 'db' as key and
    use key_length= 0 as neither table_cache_key or key_length will be used).
*/

void init_tmp_table_share(THD *thd, TABLE_SHARE *share, const char *key,
                          uint key_length, const char *table_name,
                          const char *path)
{
  DBUG_ENTER("init_tmp_table_share");
  DBUG_PRINT("enter", ("table: '%s'.'%s'", key, table_name));

  bzero((char*) share, sizeof(*share));
  /*
    This can't be MY_THREAD_SPECIFIC for slaves as they are freed
    during cleanup() from Relay_log_info::close_temporary_tables()
  */
  init_sql_alloc(&share->mem_root, TABLE_ALLOC_BLOCK_SIZE, 0, 
                 MYF(thd->slave_thread ? 0 : MY_THREAD_SPECIFIC));
  share->table_category=         TABLE_CATEGORY_TEMPORARY;
  share->tmp_table=              INTERNAL_TMP_TABLE;
  share->db.str=                 (char*) key;
  share->db.length=		 strlen(key);
  share->table_cache_key.str=    (char*) key;
  share->table_cache_key.length= key_length;
  share->table_name.str=         (char*) table_name;
  share->table_name.length=      strlen(table_name);
  share->path.str=               (char*) path;
  share->normalized_path.str=    (char*) path;
  share->path.length= share->normalized_path.length= strlen(path);
  share->frm_version= 		 FRM_VER_TRUE_VARCHAR;

  share->cached_row_logging_check= -1;

  /*
    table_map_id is also used for MERGE tables to suppress repeated
    compatibility checks.
  */
  share->table_map_id= (ulong) thd->query_id;

  share->used_tables.empty();
  share->free_tables.empty();
  share->m_flush_tickets.empty();

  DBUG_VOID_RETURN;
}


/**
  Release resources (plugins) used by the share and free its memory.
  TABLE_SHARE is self-contained -- it's stored in its own MEM_ROOT.
  Free this MEM_ROOT.
*/

void TABLE_SHARE::destroy()
{
  uint idx;
  KEY *info_it;

  if (tmp_table == NO_TMP_TABLE)
    mysql_mutex_lock(&LOCK_ha_data);
  free_root(&stats_cb.mem_root, MYF(0));
  stats_cb.stats_can_be_read= FALSE;
  stats_cb.stats_is_read= FALSE;
  if (tmp_table == NO_TMP_TABLE)
    mysql_mutex_unlock(&LOCK_ha_data);

  /* The mutex is initialized only for shares that are part of the TDC */
  if (tmp_table == NO_TMP_TABLE)
    mysql_mutex_destroy(&LOCK_ha_data);
  my_hash_free(&name_hash);

  plugin_unlock(NULL, db_plugin);
  db_plugin= NULL;

  /* Release fulltext parsers */
  info_it= key_info;
  for (idx= keys; idx; idx--, info_it++)
  {
    if (info_it->flags & HA_USES_PARSER)
    {
      plugin_unlock(NULL, info_it->parser);
      info_it->flags= 0;
    }
  }
  if (ha_data_destroy)
  {
    ha_data_destroy(ha_data);
    ha_data_destroy= NULL;
  }
#ifdef WITH_PARTITION_STORAGE_ENGINE
  if (ha_part_data_destroy)
  {
    ha_part_data_destroy(ha_part_data);
    ha_part_data_destroy= NULL;
  }
#endif /* WITH_PARTITION_STORAGE_ENGINE */
  /*
    Make a copy since the share is allocated in its own root,
    and free_root() updates its argument after freeing the memory.
  */
  MEM_ROOT own_root= mem_root;
  free_root(&own_root, MYF(0));
}

/*
  Free table share and memory used by it

  SYNOPSIS
    free_table_share()
    share		Table share
*/

void free_table_share(TABLE_SHARE *share)
{
  DBUG_ENTER("free_table_share");
  DBUG_PRINT("enter", ("table: %s.%s", share->db.str, share->table_name.str));
  DBUG_ASSERT(share->ref_count == 0);

  if (share->m_flush_tickets.is_empty())
  {
    /*
      No threads are waiting for this share to be flushed (the
      share is not old, is for a temporary table, or just nobody
      happens to be waiting for it). Destroy it.
    */
    share->destroy();
  }
  else
  {
    Wait_for_flush_list::Iterator it(share->m_flush_tickets);
    Wait_for_flush *ticket;
    /*
      We're about to iterate over a list that is used
      concurrently. Make sure this never happens without a lock.
    */
    mysql_mutex_assert_owner(&LOCK_open);

    while ((ticket= it++))
      (void) ticket->get_ctx()->m_wait.set_status(MDL_wait::GRANTED);
    /*
      If there are threads waiting for this share to be flushed,
      the last one to receive the notification will destroy the
      share. At this point the share is removed from the table
      definition cache, so is OK to proceed here without waiting
      for this thread to do the work.
    */
  }
  DBUG_VOID_RETURN;
}


/**
  Return TRUE if a table name matches one of the system table names.
  Currently these are:

  help_category, help_keyword, help_relation, help_topic,
  proc, event
  time_zone, time_zone_leap_second, time_zone_name, time_zone_transition,
  time_zone_transition_type

  This function trades accuracy for speed, so may return false
  positives. Presumably mysql.* database is for internal purposes only
  and should not contain user tables.
*/

inline bool is_system_table_name(const char *name, uint length)
{
  CHARSET_INFO *ci= system_charset_info;

  return (
          /* mysql.proc table */
          (length == 4 &&
           my_tolower(ci, name[0]) == 'p' && 
           my_tolower(ci, name[1]) == 'r' &&
           my_tolower(ci, name[2]) == 'o' &&
           my_tolower(ci, name[3]) == 'c') ||

          (length > 4 &&
           (
            /* one of mysql.help* tables */
            (my_tolower(ci, name[0]) == 'h' &&
             my_tolower(ci, name[1]) == 'e' &&
             my_tolower(ci, name[2]) == 'l' &&
             my_tolower(ci, name[3]) == 'p') ||

            /* one of mysql.time_zone* tables */
            (my_tolower(ci, name[0]) == 't' &&
             my_tolower(ci, name[1]) == 'i' &&
             my_tolower(ci, name[2]) == 'm' &&
             my_tolower(ci, name[3]) == 'e') ||

            /* one of mysql.*_stat tables */
            (my_tolower(ci, name[length-5]) == 's' &&
             my_tolower(ci, name[length-4]) == 't' &&
             my_tolower(ci, name[length-3]) == 'a' &&
             my_tolower(ci, name[length-2]) == 't' &&
             my_tolower(ci, name[length-1]) == 's') ||
           
            /* mysql.event table */
            (my_tolower(ci, name[0]) == 'e' &&
             my_tolower(ci, name[1]) == 'v' &&
             my_tolower(ci, name[2]) == 'e' &&
             my_tolower(ci, name[3]) == 'n' &&
             my_tolower(ci, name[4]) == 't')
            )
           )
         );
}


/*
  Read table definition from a binary / text based .frm file
  
  SYNOPSIS
  open_table_def()
  thd		Thread handler
  share		Fill this with table definition
  db_flags	Bit mask of the following flags: OPEN_VIEW

  NOTES
    This function is called when the table definition is not cached in
    table_def_cache
    The data is returned in 'share', which is alloced by
    alloc_table_share().. The code assumes that share is initialized.
*/

enum open_frm_error open_table_def(THD *thd, TABLE_SHARE *share, uint flags)
{
  bool error_given= false;
  File file;
  MY_STAT stats;
  uchar *buf;
  uchar head[FRM_HEADER_SIZE];
  char	path[FN_REFLEN];
  size_t frmlen;
  DBUG_ENTER("open_table_def");
  DBUG_PRINT("enter", ("table: '%s'.'%s'  path: '%s'", share->db.str,
                       share->table_name.str, share->normalized_path.str));

  share->error= OPEN_FRM_OPEN_ERROR;

  strxmov(path, share->normalized_path.str, reg_ext, NullS);
  file= mysql_file_open(key_file_frm, path, O_RDONLY | O_SHARE, MYF(0));
  if (file < 0)
  {
    if ((flags & GTS_TABLE) && (flags & GTS_FORCE_DISCOVERY))
    {
      ha_discover_table(thd, share);
      error_given= true;
    }
    goto err_not_open;
  }

  if (mysql_file_read(file, head, sizeof(head), MYF(MY_NABP)))
  {
    share->error = my_errno == HA_ERR_FILE_TOO_SHORT
                      ? OPEN_FRM_CORRUPTED : OPEN_FRM_READ_ERROR;
    goto err;
  }

  if (memcmp(head, STRING_WITH_LEN("TYPE=VIEW\n")) == 0)
  {
    share->is_view= 1;
    share->error= flags & GTS_VIEW ? OPEN_FRM_OK : OPEN_FRM_NOT_A_TABLE;
    goto err;
  }
  if (!is_binary_frm_header(head))
  {
    /* No handling of text based files yet */
    share->error = OPEN_FRM_CORRUPTED;
    goto err;
  }
  if (!(flags & GTS_TABLE))
  {
    share->error = OPEN_FRM_NOT_A_VIEW;
    goto err;
  }

  if (my_fstat(file, &stats, MYF(0)))
    goto err;

  frmlen= min(FRM_MAX_SIZE, stats.st_size); // safety

  if (!(buf= (uchar*)my_malloc(frmlen, MYF(MY_THREAD_SPECIFIC|MY_WME))))
    goto err;

  memcpy(buf, head, sizeof(head));

  if (mysql_file_read(file, buf + sizeof(head),
                      frmlen - sizeof(head), MYF(MY_NABP)))
  {
    share->error = my_errno == HA_ERR_FILE_TOO_SHORT
                      ? OPEN_FRM_CORRUPTED : OPEN_FRM_READ_ERROR;
    my_free(buf);
    goto err;
  }
  mysql_file_close(file, MYF(MY_WME));

  share->init_from_binary_frm_image(thd, false, buf, frmlen);
  error_given= true; // init_from_binary_frm_image has already called my_error()
  my_free(buf);

  goto err_not_open;

err:
  mysql_file_close(file, MYF(MY_WME));

err_not_open:
  if (share->error && !error_given)
  {
    share->open_errno= my_errno;
    open_table_error(share, share->error, share->open_errno);
  }

  DBUG_RETURN(share->error);
}


/**
  Read data from a binary .frm file image into a TABLE_SHARE

  @note
  frm bytes at the following offsets are unused in MariaDB 10.0:

  8..9    (used to be the number of "form names")
  28..29  (used to be key_info_length)

  They're still set, for compatibility reasons, but never read.

  42..46 are unused since 5.0 (were for RAID support)
  Also, there're few unused bytes in forminfo.

*/

int TABLE_SHARE::init_from_binary_frm_image(THD *thd, bool write,
                                            const uchar *frm_image,
                                            size_t frm_length)
{
  TABLE_SHARE *share= this;
  uint new_frm_ver, field_pack_length, new_field_pack_flag;
  uint interval_count, interval_parts, read_length, int_length;
  uint db_create_options, keys, key_parts, n_length;
  uint com_length, null_bit_pos;
  uint extra_rec_buf_length;
  uint i,j;
  bool use_hash;
  char *keynames, *names, *comment_pos;
  const uchar *forminfo, *extra2;
  const uchar *frm_image_end = frm_image + frm_length;
  uchar *record, *null_flags, *null_pos;
  const uchar *disk_buff, *strpos;
  ulong pos, record_offset; 
  ulong *rec_per_key= NULL;
  ulong rec_buff_length;
  handler *handler_file= 0;
  KEY	*keyinfo;
  KEY_PART_INFO *key_part= NULL;
  Field  **field_ptr, *reg_field;
  const char **interval_array;
  enum legacy_db_type legacy_db_type;
  my_bitmap_map *bitmaps;
  bool null_bits_are_used;
  uint vcol_screen_length, UNINIT_VAR(options_len);
  char *vcol_screen_pos;
  const uchar *options= 0;
  KEY first_keyinfo;
  uint len;
  KEY_PART_INFO *first_key_part= NULL;
  uint ext_key_parts= 0;
  uint first_key_parts= 0;
  plugin_ref se_plugin= 0;
  keyinfo= &first_keyinfo;
  share->ext_key_parts= 0;
  MEM_ROOT **root_ptr, *old_root;
  DBUG_ENTER("TABLE_SHARE::init_from_binary_frm_image");

  root_ptr= my_pthread_getspecific_ptr(MEM_ROOT**, THR_MALLOC);
  old_root= *root_ptr;
  *root_ptr= &share->mem_root;

  if (write && write_frm_image(frm_image, frm_length))
    goto err;

  if (frm_length < FRM_HEADER_SIZE + FRM_FORMINFO_SIZE)
    goto err;

  new_field_pack_flag= frm_image[27];
  new_frm_ver= (frm_image[2] - FRM_VER);
  field_pack_length= new_frm_ver < 2 ? 11 : 17;

  /* Length of the MariaDB extra2 segment in the form file. */
  len = uint2korr(frm_image+4);
  extra2= frm_image + 64;

  if (*extra2 != '/')   // old frm had '/' there
  {
    const uchar *e2end= extra2 + len;
    while (extra2 < e2end)
    {
      uchar type= *extra2++;
      size_t length= *extra2++;
      if (!length)
      {
        length= uint2korr(extra2);
        extra2+=2;
        if (length < 256)
          goto err;
      }
      switch (type) {
      case EXTRA2_TABLEDEF_VERSION:
        if (tabledef_version.str) // see init_from_sql_statement_string()
        {
          if (length != tabledef_version.length ||
              memcmp(extra2, tabledef_version.str, length))
            goto err;
        }
        else
        {
          uchar *buf= (uchar*) alloc_root(&mem_root, length);
          if (!buf)
            goto err;
          memcpy(buf, extra2, length);
          tabledef_version.str= buf;
          tabledef_version.length= length;
        }
        break;
      case EXTRA2_ENGINE_TABLEOPTS:
        if (options)
          goto err;
        /* remember but delay parsing until we have read fields and keys */
        options= extra2;
        options_len= length;
        break;
      default:
        /* abort frm parsing if it's an unknown but important extra2 value */
        if (type >= 128)
          goto err;
      }
      extra2+= length;
    }
    if (extra2 > e2end)
      goto err;
  }

  if (frm_length < FRM_HEADER_SIZE + len ||
      !(pos= uint4korr(frm_image + FRM_HEADER_SIZE + len)))
    goto err;

  forminfo= frm_image + pos;
  if (forminfo + FRM_FORMINFO_SIZE >= frm_image_end)
    goto err;

  share->frm_version= frm_image[2];
  /*
    Check if .frm file created by MySQL 5.0. In this case we want to
    display CHAR fields as CHAR and not as VARCHAR.
    We do it this way as we want to keep the old frm version to enable
    MySQL 4.1 to read these files.
  */
  if (share->frm_version == FRM_VER_TRUE_VARCHAR -1 && frm_image[33] == 5)
    share->frm_version= FRM_VER_TRUE_VARCHAR;

#ifdef WITH_PARTITION_STORAGE_ENGINE
  if (frm_image[61] &&
      !(share->default_part_db_type= 
        ha_checktype(thd, (enum legacy_db_type) (uint) frm_image[61], 1, 0)))
    goto err;
  DBUG_PRINT("info", ("default_part_db_type = %u", frm_image[61]));
#endif
  legacy_db_type= (enum legacy_db_type) (uint) frm_image[3];
  /*
    if the storage engine is dynamic, no point in resolving it by its
    dynamically allocated legacy_db_type. We will resolve it later by name.
  */
  if (legacy_db_type > DB_TYPE_UNKNOWN && 
      legacy_db_type < DB_TYPE_FIRST_DYNAMIC)
    se_plugin= ha_lock_engine(NULL, ha_checktype(thd, legacy_db_type, 0, 0));
  share->db_create_options= db_create_options= uint2korr(frm_image+30);
  share->db_options_in_use= share->db_create_options;
  share->mysql_version= uint4korr(frm_image+51);
  share->null_field_first= 0;
  if (!frm_image[32])				// New frm file in 3.23
  {
    share->avg_row_length= uint4korr(frm_image+34);
    share->transactional= (ha_choice) (frm_image[39] & 3);
    share->page_checksum= (ha_choice) ((frm_image[39] >> 2) & 3);
    share->row_type= (enum row_type) frm_image[40];
    share->table_charset= get_charset((((uint) frm_image[41]) << 8) + 
                                        (uint) frm_image[38],MYF(0));
    share->null_field_first= 1;
  }
  if (!share->table_charset)
  {
    /* unknown charset in frm_image[38] or pre-3.23 frm */
    if (use_mb(default_charset_info))
    {
      /* Warn that we may be changing the size of character columns */
      sql_print_warning("'%s' had no or invalid character set, "
                        "and default character set is multi-byte, "
                        "so character column sizes may have changed",
                        share->path.str);
    }
    share->table_charset= default_charset_info;
  }
  share->db_record_offset= 1;
  if (db_create_options & HA_OPTION_LONG_BLOB_PTR)
    share->blob_ptr_size= portable_sizeof_char_ptr;
  share->max_rows= uint4korr(frm_image+18);
  share->min_rows= uint4korr(frm_image+22);

  /* Read keyinformation */
  disk_buff= frm_image + uint2korr(frm_image+6);

  if (disk_buff + 6 >= frm_image_end)
    goto err;

  if (disk_buff[0] & 0x80)
  {
    share->keys=      keys=      (disk_buff[1] << 7) | (disk_buff[0] & 0x7f);
    share->key_parts= key_parts= uint2korr(disk_buff+2);
  }
  else
  {
    share->keys=      keys=      disk_buff[0];
    share->key_parts= key_parts= disk_buff[1];
  }
  share->keys_for_keyread.init(0);
  share->keys_in_use.init(keys);

  /*
    At this point we don't have enough information read from the frm file
    to get a proper handlerton for the interesting engine in order to get
    properties of this engine.
  */   
  /* Currently only InnoDB can use extended keys */
  share->set_use_ext_keys_flag(legacy_db_type == DB_TYPE_INNODB);

  len= (uint) uint2korr(disk_buff+4);
  if (!keys)
  {  
    if (!(keyinfo = (KEY*) alloc_root(&share->mem_root, len)))
      goto err;
    bzero((char*) keyinfo, len);
    key_part= reinterpret_cast<KEY_PART_INFO*> (keyinfo+keys);
  }
  strpos= disk_buff+6;

  /*
    If share->use_ext_keys is set to TRUE we assume that any key
    can be extended by the components of the primary key whose
    definition is read first from the frm file.
    For each key only those fields of the assumed primary key are
    added that are not included in the proper key definition. 
    If after all it turns out that there is no primary key the
    added components are removed from each key.

    When in the future we support others schemes of extending of
    secondary keys with components of the primary key we'll have
    to change the type of this flag for an enumeration type.                 
  */   

  for (i=0 ; i < keys ; i++, keyinfo++)
  {
    if (new_frm_ver >= 3)
    {
      if (strpos + 8 >= frm_image_end)
        goto err;
      keyinfo->flags=	   (uint) uint2korr(strpos) ^ HA_NOSAME;
      keyinfo->key_length= (uint) uint2korr(strpos+2);
      keyinfo->key_parts=  (uint) strpos[4];
      keyinfo->algorithm=  (enum ha_key_alg) strpos[5];
      keyinfo->block_size= uint2korr(strpos+6);
      strpos+=8;
    }
    else
    {
      if (strpos + 4 >= frm_image_end)
        goto err;
      keyinfo->flags=	 ((uint) strpos[0]) ^ HA_NOSAME;
      keyinfo->key_length= (uint) uint2korr(strpos+1);
      keyinfo->key_parts=  (uint) strpos[3];
      keyinfo->algorithm= HA_KEY_ALG_UNDEF;
      strpos+=4;
    }

    if (i == 0)
    {
      ext_key_parts= key_parts +
	             (share->use_ext_keys ? first_keyinfo.key_parts*(keys-1) : 0); 
    
      n_length=keys * sizeof(KEY) + ext_key_parts * sizeof(KEY_PART_INFO);
      if (!(keyinfo= (KEY*) alloc_root(&share->mem_root,
				       n_length + len)))
        goto err;                                   /* purecov: inspected */
      bzero((char*) keyinfo,n_length);
      share->key_info= keyinfo;
      key_part= reinterpret_cast<KEY_PART_INFO*> (keyinfo + keys);

      if (!(rec_per_key= (ulong*) alloc_root(&share->mem_root,
                                             sizeof(ulong) * ext_key_parts)))
        goto err;
      first_key_part= key_part;
      first_key_parts= first_keyinfo.key_parts;
      keyinfo->flags= first_keyinfo.flags;
      keyinfo->key_length= first_keyinfo.key_length;
      keyinfo->key_parts= first_keyinfo.key_parts;
      keyinfo->algorithm= first_keyinfo.algorithm;
      if (new_frm_ver >= 3)
        keyinfo->block_size= first_keyinfo.block_size;
    }

    keyinfo->key_part=	 key_part;
    keyinfo->rec_per_key= rec_per_key;
    for (j=keyinfo->key_parts ; j-- ; key_part++)
    {
      if (strpos + (new_frm_ver >= 1 ? 9 : 7) >= frm_image_end)
        goto err;
      *rec_per_key++=0;
      key_part->fieldnr=	(uint16) (uint2korr(strpos) & FIELD_NR_MASK);
      key_part->offset= (uint) uint2korr(strpos+2)-1;
      key_part->key_type=	(uint) uint2korr(strpos+5);
      // key_part->field=	(Field*) 0;	// Will be fixed later
      if (new_frm_ver >= 1)
      {
	key_part->key_part_flag= *(strpos+4);
	key_part->length=	(uint) uint2korr(strpos+7);
	strpos+=9;
      }
      else
      {
	key_part->length=	*(strpos+4);
	key_part->key_part_flag=0;
	if (key_part->length > 128)
	{
	  key_part->length&=127;		/* purecov: inspected */
	  key_part->key_part_flag=HA_REVERSE_SORT; /* purecov: inspected */
	}
	strpos+=7;
      }
      key_part->store_length=key_part->length;
    }
    keyinfo->ext_key_parts= keyinfo->key_parts;
    keyinfo->ext_key_flags= keyinfo->flags;
    keyinfo->ext_key_part_map= 0;
    if (share->use_ext_keys && i)
    {
      keyinfo->ext_key_part_map= 0;
      for (j= 0; 
           j < first_key_parts && keyinfo->ext_key_parts < MAX_REF_PARTS;
           j++)
      {
        uint key_parts= keyinfo->key_parts;
        KEY_PART_INFO* curr_key_part= keyinfo->key_part;
        KEY_PART_INFO* curr_key_part_end= curr_key_part+key_parts;
        for ( ; curr_key_part < curr_key_part_end; curr_key_part++)
        {
          if (curr_key_part->fieldnr == first_key_part[j].fieldnr)
            break;
        }
        if (curr_key_part == curr_key_part_end)
        {
          *key_part++= first_key_part[j];
          *rec_per_key++= 0;
          keyinfo->ext_key_parts++;
          keyinfo->ext_key_part_map|= 1 << j;
        }
      }
      if (j == first_key_parts)
        keyinfo->ext_key_flags= keyinfo->flags | HA_EXT_NOSAME;
    }
    share->ext_key_parts+= keyinfo->ext_key_parts;  
  }
  keynames=(char*) key_part;
  strpos+= strnmov(keynames, (char *) strpos, frm_image_end - strpos) - keynames;
  if (*strpos++) // key names are \0-terminated
    goto err;

  //reading index comments
  for (keyinfo= share->key_info, i=0; i < keys; i++, keyinfo++)
  {
    if (keyinfo->flags & HA_USES_COMMENT)
    {
      if (strpos + 2 >= frm_image_end)
        goto err;
      keyinfo->comment.length= uint2korr(strpos);
      strpos+= 2;

      if (strpos + keyinfo->comment.length >= frm_image_end)
        goto err;
      keyinfo->comment.str= strmake_root(&share->mem_root, (char*) strpos,
                                         keyinfo->comment.length);
      strpos+= keyinfo->comment.length;
    } 
    DBUG_ASSERT(test(keyinfo->flags & HA_USES_COMMENT) == 
               (keyinfo->comment.length > 0));
  }

  share->reclength = uint2korr((frm_image+16));
  share->stored_rec_length= share->reclength;
  if (frm_image[26] == 1)
    share->system= 1;				/* one-record-database */

  record_offset= (ulong) (uint2korr(frm_image+6)+
                          ((uint2korr(frm_image+14) == 0xffff ?
                            uint4korr(frm_image+47) : uint2korr(frm_image+14))));

  if (record_offset + share->reclength >= frm_length)
    goto err;
 
  if ((n_length= uint4korr(frm_image+55)))
  {
    /* Read extra data segment */
    const uchar *next_chunk, *buff_end;
    DBUG_PRINT("info", ("extra segment size is %u bytes", n_length));
    next_chunk= frm_image + record_offset + share->reclength;
    buff_end= next_chunk + n_length;

    if (buff_end >= frm_image_end)
      goto err;

    share->connect_string.length= uint2korr(next_chunk);
    if (!(share->connect_string.str= strmake_root(&share->mem_root,
                                                  (char*) next_chunk + 2,
                                                  share->connect_string.
                                                  length)))
    {
      goto err;
    }
    next_chunk+= share->connect_string.length + 2;
    if (next_chunk + 2 < buff_end)
    {
      uint str_db_type_length= uint2korr(next_chunk);
      LEX_STRING name;
      name.str= (char*) next_chunk + 2;
      name.length= str_db_type_length;

      plugin_ref tmp_plugin= ha_resolve_by_name(thd, &name);
      if (tmp_plugin != NULL && !plugin_equals(tmp_plugin, se_plugin))
      {
        if (se_plugin)
        {
          /* bad file, legacy_db_type did not match the name */
          goto err;
        }
        /*
          tmp_plugin is locked with a local lock.
          we unlock the old value of se_plugin before
          replacing it with a globally locked version of tmp_plugin
        */
        plugin_unlock(NULL, se_plugin);
        se_plugin= plugin_lock(NULL, tmp_plugin);
      }
#ifdef WITH_PARTITION_STORAGE_ENGINE
      else if (str_db_type_length == 9 &&
               !strncmp((char *) next_chunk + 2, "partition", 9))
      {
        /*
          Use partition handler
          tmp_plugin is locked with a local lock.
          we unlock the old value of se_plugin before
          replacing it with a globally locked version of tmp_plugin
        */
        /* Check if the partitioning engine is ready */
        if (!plugin_is_ready(&name, MYSQL_STORAGE_ENGINE_PLUGIN))
        {
          my_error(ER_OPTION_PREVENTS_STATEMENT, MYF(0),
                   "--skip-partition");
          goto err;
        }
        plugin_unlock(NULL, se_plugin);
        se_plugin= ha_lock_engine(NULL, partition_hton);
      }
#endif
      else if (!tmp_plugin)
      {
        /* purecov: begin inspected */
        name.str[name.length]=0;
        my_error(ER_UNKNOWN_STORAGE_ENGINE, MYF(0), name.str);
        goto err;
        /* purecov: end */
      }
      next_chunk+= str_db_type_length + 2;
    }
    if (next_chunk + 5 < buff_end)
    {
      uint32 partition_info_str_len = uint4korr(next_chunk);
#ifdef WITH_PARTITION_STORAGE_ENGINE
      if ((share->partition_info_buffer_size=
             share->partition_info_str_len= partition_info_str_len))
      {
        if (!(share->partition_info_str= (char*)
              memdup_root(&share->mem_root, next_chunk + 4,
                          partition_info_str_len + 1)))
        {
          goto err;
        }
      }
#else
      if (partition_info_str_len)
      {
        DBUG_PRINT("info", ("WITH_PARTITION_STORAGE_ENGINE is not defined"));
        goto err;
      }
#endif
      next_chunk+= 5 + partition_info_str_len;
    }
    if (share->mysql_version >= 50110 && next_chunk < buff_end)
    {
      /* New auto_partitioned indicator introduced in 5.1.11 */
#ifdef WITH_PARTITION_STORAGE_ENGINE
      share->auto_partitioned= *next_chunk;
#endif
      next_chunk++;
    }
    keyinfo= share->key_info;
    for (i= 0; i < keys; i++, keyinfo++)
    {
      if (keyinfo->flags & HA_USES_PARSER)
      {
        LEX_STRING parser_name;
        if (next_chunk >= buff_end)
        {
          DBUG_PRINT("error",
                     ("fulltext key uses parser that is not defined in .frm"));
          goto err;
        }
        parser_name.str= (char*) next_chunk;
        parser_name.length= strlen((char*) next_chunk);
        next_chunk+= parser_name.length + 1;
        keyinfo->parser= my_plugin_lock_by_name(NULL, &parser_name,
                                                MYSQL_FTPARSER_PLUGIN);
        if (! keyinfo->parser)
        {
          my_error(ER_PLUGIN_IS_NOT_LOADED, MYF(0), parser_name.str);
          goto err;
        }
      }
    }

    if (forminfo[46] == (uchar)255)
    {
      //reading long table comment
      if (next_chunk + 2 > buff_end)
      {
          DBUG_PRINT("error",
                     ("long table comment is not defined in .frm"));
          goto err;
      }
      share->comment.length = uint2korr(next_chunk);
      if (! (share->comment.str= strmake_root(&share->mem_root,
             (char*)next_chunk + 2, share->comment.length)))
      {
          goto err;
      }
      next_chunk+= 2 + share->comment.length;
    }

    DBUG_ASSERT(next_chunk <= buff_end);

    if (share->db_create_options & HA_OPTION_TEXT_CREATE_OPTIONS_legacy)
    {
      if (options)
        goto err;
      options_len= uint4korr(next_chunk);
      options= next_chunk + 4;
      next_chunk+= options_len + 4;
    }
    DBUG_ASSERT(next_chunk <= buff_end);
  }
  share->key_block_size= uint2korr(frm_image+62);

  if (share->db_plugin && !plugin_equals(share->db_plugin, se_plugin))
    goto err; // wrong engine (someone changed the frm under our feet?)

  extra_rec_buf_length= uint2korr(frm_image+59);
  rec_buff_length= ALIGN_SIZE(share->reclength + 1 + extra_rec_buf_length);
  share->rec_buff_length= rec_buff_length;
  if (!(record= (uchar *) alloc_root(&share->mem_root,
                                     rec_buff_length)))
    goto err;                          /* purecov: inspected */
  share->default_values= record;
  memcpy(record, frm_image + record_offset, share->reclength);

  disk_buff= frm_image + pos + FRM_FORMINFO_SIZE;

  share->fields= uint2korr(forminfo+258);
  pos= uint2korr(forminfo+260);   /* Length of all screens */
  n_length= uint2korr(forminfo+268);
  interval_count= uint2korr(forminfo+270);
  interval_parts= uint2korr(forminfo+272);
  int_length= uint2korr(forminfo+274);
  share->null_fields= uint2korr(forminfo+282);
  com_length= uint2korr(forminfo+284);
  vcol_screen_length= uint2korr(forminfo+286);
  share->vfields= 0;
  share->default_fields= 0;
  share->stored_fields= share->fields;
  if (forminfo[46] != (uchar)255)
  {
    share->comment.length=  (int) (forminfo[46]);
    share->comment.str= strmake_root(&share->mem_root, (char*) forminfo+47,
                                     share->comment.length);
  }

  DBUG_PRINT("info",("i_count: %d  i_parts: %d  index: %d  n_length: %d  int_length: %d  com_length: %d  vcol_screen_length: %d", interval_count,interval_parts, share->keys,n_length,int_length, com_length, vcol_screen_length));


  if (!(field_ptr = (Field **)
	alloc_root(&share->mem_root,
		   (uint) ((share->fields+1)*sizeof(Field*)+
			   interval_count*sizeof(TYPELIB)+
			   (share->fields+interval_parts+
			    keys+3)*sizeof(char *)+
			   (n_length+int_length+com_length+
			       vcol_screen_length)))))
    goto err;                           /* purecov: inspected */

  share->field= field_ptr;
  read_length=(uint) (share->fields * field_pack_length +
		      pos+ (uint) (n_length+int_length+com_length+
		                   vcol_screen_length));
  strpos= disk_buff+pos;

  share->intervals= (TYPELIB*) (field_ptr+share->fields+1);
  interval_array= (const char **) (share->intervals+interval_count);
  names= (char*) (interval_array+share->fields+interval_parts+keys+3);
  if (!interval_count)
    share->intervals= 0;			// For better debugging
  memcpy((char*) names, strpos+(share->fields*field_pack_length),
	 (uint) (n_length+int_length));
  comment_pos= names+(n_length+int_length);
  memcpy(comment_pos, disk_buff+read_length-com_length-vcol_screen_length, 
         com_length);
  vcol_screen_pos= names+(n_length+int_length+com_length);
  memcpy(vcol_screen_pos, disk_buff+read_length-vcol_screen_length, 
         vcol_screen_length);

  fix_type_pointers(&interval_array, &share->fieldnames, 1, &names);
  if (share->fieldnames.count != share->fields)
    goto err;
  fix_type_pointers(&interval_array, share->intervals, interval_count,
		    &names);

  {
    /* Set ENUM and SET lengths */
    TYPELIB *interval;
    for (interval= share->intervals;
         interval < share->intervals + interval_count;
         interval++)
    {
      uint count= (uint) (interval->count + 1) * sizeof(uint);
      if (!(interval->type_lengths= (uint *) alloc_root(&share->mem_root,
                                                        count)))
        goto err;
      for (count= 0; count < interval->count; count++)
      {
        char *val= (char*) interval->type_names[count];
        interval->type_lengths[count]= strlen(val);
      }
      interval->type_lengths[count]= 0;
    }
  }

  if (keynames)
    fix_type_pointers(&interval_array, &share->keynames, 1, &keynames);

 /* Allocate handler */
  if (!(handler_file= get_new_handler(share, thd->mem_root,
                                      plugin_data(se_plugin, handlerton *))))
    goto err;

  record= share->default_values-1;              /* Fieldstart = 1 */
  null_bits_are_used= share->null_fields != 0;
  if (share->null_field_first)
  {
    null_flags= null_pos= record+1;
    null_bit_pos= (db_create_options & HA_OPTION_PACK_RECORD) ? 0 : 1;
    /*
      null_bytes below is only correct under the condition that
      there are no bit fields.  Correct values is set below after the
      table struct is initialized
    */
    share->null_bytes= (share->null_fields + null_bit_pos + 7) / 8;
  }
#ifndef WE_WANT_TO_SUPPORT_VERY_OLD_FRM_FILES
  else
  {
    share->null_bytes= (share->null_fields+7)/8;
    null_flags= null_pos= record + 1 + share->reclength - share->null_bytes;
    null_bit_pos= 0;
  }
#endif

  use_hash= share->fields >= MAX_FIELDS_BEFORE_HASH;
  if (use_hash)
    use_hash= !my_hash_init(&share->name_hash,
                            system_charset_info,
                            share->fields,0,0,
                            (my_hash_get_key) get_field_name,0,0);

  for (i=0 ; i < share->fields; i++, strpos+=field_pack_length, field_ptr++)
  {
    uint pack_flag, interval_nr, unireg_type, recpos, field_length;
    uint vcol_info_length=0;
    uint vcol_expr_length=0;
    enum_field_types field_type;
    CHARSET_INFO *charset=NULL;
    Field::geometry_type geom_type= Field::GEOM_GEOMETRY;
    LEX_STRING comment;
    Virtual_column_info *vcol_info= 0;
    bool fld_stored_in_db= TRUE;

    if (new_frm_ver >= 3)
    {
      /* new frm file in 4.1 */
      field_length= uint2korr(strpos+3);
      recpos=	    uint3korr(strpos+5);
      pack_flag=    uint2korr(strpos+8);
      unireg_type=  (uint) strpos[10];
      interval_nr=  (uint) strpos[12];
      uint comment_length=uint2korr(strpos+15);
      field_type=(enum_field_types) (uint) strpos[13];

      /* charset and geometry_type share the same byte in frm */
      if (field_type == MYSQL_TYPE_GEOMETRY)
      {
#ifdef HAVE_SPATIAL
	geom_type= (Field::geometry_type) strpos[14];
	charset= &my_charset_bin;
#else
	goto err;
#endif
      }
      else
      {
        uint csid= strpos[14] + (((uint) strpos[11]) << 8);
        if (!csid)
          charset= &my_charset_bin;
        else if (!(charset= get_charset(csid, MYF(0))))
        {
          const char *csname= get_charset_name((uint) csid);
          char tmp[10];
          if (!csname || csname[0] =='?')
          {
            my_snprintf(tmp, sizeof(tmp), "#%d", csid);
            csname= tmp;
          }
          my_printf_error(ER_UNKNOWN_COLLATION,
                          "Unknown collation '%s' in table '%-.64s' definition", 
                          MYF(0), csname, share->table_name.str);
          goto err;
        }
      }

      if ((uchar)field_type == (uchar)MYSQL_TYPE_VIRTUAL)
      {
        DBUG_ASSERT(interval_nr); // Expect non-null expression
        /* 
          The interval_id byte in the .frm file stores the length of the
          expression statement for a virtual column.
        */
        vcol_info_length= interval_nr;
        interval_nr= 0;
      }

      if (!comment_length)
      {
	comment.str= (char*) "";
	comment.length=0;
      }
      else
      {
	comment.str=    (char*) comment_pos;
	comment.length= comment_length;
	comment_pos+=   comment_length;
      }

      if (vcol_info_length)
      {
        /*
          Get virtual column data stored in the .frm file as follows:
          byte 1      = 1 | 2
          byte 2      = sql_type
          byte 3      = flags (as of now, 0 - no flags, 1 - field is physically stored)
          [byte 4]    = optional interval_id for sql_type (only if byte 1 == 2) 
          next byte ...  = virtual column expression (text data)
        */
        vcol_info= new Virtual_column_info();
        bool opt_interval_id= (uint)vcol_screen_pos[0] == 2;
        field_type= (enum_field_types) (uchar) vcol_screen_pos[1];
        if (opt_interval_id)
          interval_nr= (uint)vcol_screen_pos[3];
        else if ((uint)vcol_screen_pos[0] != 1)
          goto err;

        fld_stored_in_db= (bool) (uint) vcol_screen_pos[2];
        vcol_expr_length= vcol_info_length -
                          (uint)(FRM_VCOL_HEADER_SIZE(opt_interval_id));
        if (!(vcol_info->expr_str.str=
              (char *)memdup_root(&share->mem_root,
                                  vcol_screen_pos +
                                  (uint) FRM_VCOL_HEADER_SIZE(opt_interval_id),
                                  vcol_expr_length)))
          goto err;
        if (opt_interval_id)
          interval_nr= (uint) vcol_screen_pos[3];
        vcol_info->expr_str.length= vcol_expr_length;
        vcol_screen_pos+= vcol_info_length;
        share->vfields++;
      }
    }
    else
    {
      field_length= (uint) strpos[3];
      recpos=	    uint2korr(strpos+4),
      pack_flag=    uint2korr(strpos+6);
      pack_flag&=   ~FIELDFLAG_NO_DEFAULT;     // Safety for old files
      unireg_type=  (uint) strpos[8];
      interval_nr=  (uint) strpos[10];

      /* old frm file */
      field_type= (enum_field_types) f_packtype(pack_flag);
      if (f_is_binary(pack_flag))
      {
        /*
          Try to choose the best 4.1 type:
          - for 4.0 "CHAR(N) BINARY" or "VARCHAR(N) BINARY" 
            try to find a binary collation for character set.
          - for other types (e.g. BLOB) just use my_charset_bin. 
        */
        if (!f_is_blob(pack_flag))
        {
          // 3.23 or 4.0 string
          if (!(charset= get_charset_by_csname(share->table_charset->csname,
                                               MY_CS_BINSORT, MYF(0))))
            charset= &my_charset_bin;
        }
        else
          charset= &my_charset_bin;
      }
      else
        charset= share->table_charset;
      bzero((char*) &comment, sizeof(comment));
    }

    if (interval_nr && charset->mbminlen > 1)
    {
      /* Unescape UCS2 intervals from HEX notation */
      TYPELIB *interval= share->intervals + interval_nr - 1;
      unhex_type2(interval);
    }
    
#ifndef TO_BE_DELETED_ON_PRODUCTION
    if (field_type == MYSQL_TYPE_NEWDECIMAL && !share->mysql_version)
    {
      /*
        Fix pack length of old decimal values from 5.0.3 -> 5.0.4
        The difference is that in the old version we stored precision
        in the .frm table while we now store the display_length
      */
      uint decimals= f_decimals(pack_flag);
      field_length= my_decimal_precision_to_length(field_length,
                                                   decimals,
                                                   f_is_dec(pack_flag) == 0);
      sql_print_error("Found incompatible DECIMAL field '%s' in %s; "
                      "Please do \"ALTER TABLE '%s' FORCE\" to fix it!",
                      share->fieldnames.type_names[i], share->table_name.str,
                      share->table_name.str);
      push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                          ER_CRASHED_ON_USAGE,
                          "Found incompatible DECIMAL field '%s' in %s; "
                          "Please do \"ALTER TABLE '%s' FORCE\" to fix it!",
                          share->fieldnames.type_names[i],
                          share->table_name.str,
                          share->table_name.str);
      share->crashed= 1;                        // Marker for CHECK TABLE
    }
#endif

    *field_ptr= reg_field=
      make_field(share, record+recpos,
		 (uint32) field_length,
		 null_pos, null_bit_pos,
		 pack_flag,
		 field_type,
		 charset,
		 geom_type,
		 (Field::utype) MTYP_TYPENR(unireg_type),
		 (interval_nr ?
		  share->intervals+interval_nr-1 :
		  (TYPELIB*) 0),
		 share->fieldnames.type_names[i]);
    if (!reg_field)				// Not supported field type
      goto err;


    reg_field->field_index= i;
    reg_field->comment=comment;
    reg_field->vcol_info= vcol_info;
    reg_field->stored_in_db= fld_stored_in_db;
    if (field_type == MYSQL_TYPE_BIT && !f_bit_as_char(pack_flag))
    {
      null_bits_are_used= 1;
      if ((null_bit_pos+= field_length & 7) > 7)
      {
        null_pos++;
        null_bit_pos-= 8;
      }
    }
    if (!(reg_field->flags & NOT_NULL_FLAG))
    {
      if (!(null_bit_pos= (null_bit_pos + 1) & 7))
        null_pos++;
    }
    if (f_no_default(pack_flag))
      reg_field->flags|= NO_DEFAULT_VALUE_FLAG;

    if (reg_field->unireg_check == Field::NEXT_NUMBER)
      share->found_next_number_field= field_ptr;

    if (use_hash && my_hash_insert(&share->name_hash, (uchar*) field_ptr))
      goto err;
    if (!reg_field->stored_in_db)
    {
      share->stored_fields--;
      if (share->stored_rec_length>=recpos)
        share->stored_rec_length= recpos-1;
    }
    if (reg_field->has_insert_default_function() ||
        reg_field->has_update_default_function())
      ++share->default_fields;
  }
  *field_ptr=0;					// End marker
  /* Sanity checks: */
  DBUG_ASSERT(share->fields>=share->stored_fields);
  DBUG_ASSERT(share->reclength>=share->stored_rec_length);

  /* Fix key->name and key_part->field */
  if (key_parts)
  {
    uint add_first_key_parts= 0;
    uint primary_key=(uint) (find_type(primary_key_name, &share->keynames,
                                       FIND_TYPE_NO_PREFIX) - 1);
    longlong ha_option= handler_file->ha_table_flags();
    keyinfo= share->key_info;

    if (share->use_ext_keys)
    { 
      if (primary_key >= MAX_KEY)
      {
        add_first_key_parts= 0;
        share->set_use_ext_keys_flag(FALSE);
      }
      else
      {
        add_first_key_parts= first_key_parts;
        /* 
          Do not add components of the primary key starting from
          the major component defined over the beginning of a field.
	*/
	for (i= 0; i < first_key_parts; i++)
	{
          uint fieldnr= keyinfo[0].key_part[i].fieldnr;
          if (share->field[fieldnr-1]->key_length() !=
              keyinfo[0].key_part[i].length)
	  {
            add_first_key_parts= i;
            break;
          }
        }
      }   
    }

    for (uint key=0 ; key < share->keys ; key++,keyinfo++)
    {
      uint usable_parts= 0;
      keyinfo->name=(char*) share->keynames.type_names[key];
      keyinfo->name_length= strlen(keyinfo->name);
      keyinfo->cache_name=
        (uchar*) alloc_root(&share->mem_root,
                            share->table_cache_key.length+
                            keyinfo->name_length + 1);
      if (keyinfo->cache_name)           // If not out of memory
      {
        uchar *pos= keyinfo->cache_name;
        memcpy(pos, share->table_cache_key.str, share->table_cache_key.length);
        memcpy(pos + share->table_cache_key.length, keyinfo->name,
               keyinfo->name_length+1);
      }

      if (ext_key_parts > share->key_parts && key)
      {
        KEY_PART_INFO *new_key_part= (keyinfo-1)->key_part +
                                     (keyinfo-1)->ext_key_parts;

        /* 
          Do not extend the key that contains a component
          defined over the beginning of a field.
	*/ 
        for (i= 0; i < keyinfo->key_parts; i++)
	{
          uint fieldnr= keyinfo->key_part[i].fieldnr;
          if (share->field[fieldnr-1]->key_length() !=
              keyinfo->key_part[i].length)
	  {
            add_first_key_parts= 0;
            break;
          }
        }

        if (add_first_key_parts < keyinfo->ext_key_parts-keyinfo->key_parts)
	{
          share->ext_key_parts-= keyinfo->ext_key_parts;
          key_part_map ext_key_part_map= keyinfo->ext_key_part_map;
          keyinfo->ext_key_parts= keyinfo->key_parts;
          keyinfo->ext_key_flags= keyinfo->flags;
	  keyinfo->ext_key_part_map= 0; 
          for (i= 0; i < add_first_key_parts; i++)
	  {
            if (ext_key_part_map & 1<<i)
	    {
              keyinfo->ext_key_part_map|= 1<<i;
	      keyinfo->ext_key_parts++;
            }
          }
          share->ext_key_parts+= keyinfo->ext_key_parts;
        }
        if (new_key_part != keyinfo->key_part)
	{
          memmove(new_key_part, keyinfo->key_part,
                  sizeof(KEY_PART_INFO) * keyinfo->ext_key_parts);
          keyinfo->key_part= new_key_part;
        }
      }
    
      /* Fix fulltext keys for old .frm files */
      if (share->key_info[key].flags & HA_FULLTEXT)
	share->key_info[key].algorithm= HA_KEY_ALG_FULLTEXT;

      if (primary_key >= MAX_KEY && (keyinfo->flags & HA_NOSAME))
      {
	/*
	  If the UNIQUE key doesn't have NULL columns and is not a part key
	  declare this as a primary key.
	*/
	primary_key=key;
        key_part= keyinfo->key_part;
	for (i=0 ; i < keyinfo->key_parts ;i++)
	{
	  uint fieldnr= key_part[i].fieldnr;
	  if (!fieldnr ||
	      share->field[fieldnr-1]->null_ptr ||
	      share->field[fieldnr-1]->key_length() !=
	      key_part[i].length)
	  {
	    primary_key=MAX_KEY;		// Can't be used
	    break;
	  }
	}
      }

      key_part= keyinfo->key_part;
      uint key_parts= share->use_ext_keys ? keyinfo->ext_key_parts :
	                                    keyinfo->key_parts;
      for (i=0; i < key_parts; key_part++, i++)
      {
        Field *field;
	if (new_field_pack_flag <= 1)
	  key_part->fieldnr= (uint16) find_field(share->field,
                                                 share->default_values,
                                                 (uint) key_part->offset,
                                                 (uint) key_part->length);
	if (!key_part->fieldnr)
          goto err;

        field= key_part->field= share->field[key_part->fieldnr-1];
        key_part->type= field->key_type();
        if (field->null_ptr)
        {
          key_part->null_offset=(uint) ((uchar*) field->null_ptr -
                                        share->default_values);
          key_part->null_bit= field->null_bit;
          key_part->store_length+=HA_KEY_NULL_LENGTH;
          keyinfo->flags|=HA_NULL_PART_KEY;
          keyinfo->key_length+= HA_KEY_NULL_LENGTH;
        }
        if (field->type() == MYSQL_TYPE_BLOB ||
            field->real_type() == MYSQL_TYPE_VARCHAR ||
            field->type() == MYSQL_TYPE_GEOMETRY)
        {
          if (field->type() == MYSQL_TYPE_BLOB ||
              field->type() == MYSQL_TYPE_GEOMETRY)
            key_part->key_part_flag|= HA_BLOB_PART;
          else
            key_part->key_part_flag|= HA_VAR_LENGTH_PART;
          key_part->store_length+=HA_KEY_BLOB_LENGTH;
          keyinfo->key_length+= HA_KEY_BLOB_LENGTH;
        }
        if (field->type() == MYSQL_TYPE_BIT)
          key_part->key_part_flag|= HA_BIT_PART;

        if (i == 0 && key != primary_key)
          field->flags |= (((keyinfo->flags & HA_NOSAME) &&
                           (keyinfo->key_parts == 1)) ?
                           UNIQUE_KEY_FLAG : MULTIPLE_KEY_FLAG);
        if (i == 0)
          field->key_start.set_bit(key);
        if (field->key_length() == key_part->length &&
            !(field->flags & BLOB_FLAG))
        {
          if (handler_file->index_flags(key, i, 0) & HA_KEYREAD_ONLY)
          {
            share->keys_for_keyread.set_bit(key);
            field->part_of_key.set_bit(key);
            if (i < keyinfo->key_parts)
              field->part_of_key_not_clustered.set_bit(key);
          }
          if (handler_file->index_flags(key, i, 1) & HA_READ_ORDER)
            field->part_of_sortkey.set_bit(key);
        }
        if (!(key_part->key_part_flag & HA_REVERSE_SORT) &&
            usable_parts == i)
          usable_parts++;			// For FILESORT
        field->flags|= PART_KEY_FLAG;
        if (key == primary_key)
        {
          field->flags|= PRI_KEY_FLAG;
          /*
            If this field is part of the primary key and all keys contains
            the primary key, then we can use any key to find this column
          */
          if (ha_option & HA_PRIMARY_KEY_IN_READ_INDEX)
          {
            if (field->key_length() == key_part->length &&
                !(field->flags & BLOB_FLAG))
              field->part_of_key= share->keys_in_use;
            if (field->part_of_sortkey.is_set(key))
              field->part_of_sortkey= share->keys_in_use;
          }
        }
        if (field->key_length() != key_part->length)
        {
#ifndef TO_BE_DELETED_ON_PRODUCTION
          if (field->type() == MYSQL_TYPE_NEWDECIMAL)
          {
            /*
              Fix a fatal error in decimal key handling that causes crashes
              on Innodb. We fix it by reducing the key length so that
              InnoDB never gets a too big key when searching.
              This allows the end user to do an ALTER TABLE to fix the
              error.
            */
            keyinfo->key_length-= (key_part->length - field->key_length());
            key_part->store_length-= (uint16)(key_part->length -
                                              field->key_length());
            key_part->length= (uint16)field->key_length();
            sql_print_error("Found wrong key definition in %s; "
                            "Please do \"ALTER TABLE '%s' FORCE \" to fix it!",
                            share->table_name.str,
                            share->table_name.str);
            push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                                ER_CRASHED_ON_USAGE,
                                "Found wrong key definition in %s; "
                                "Please do \"ALTER TABLE '%s' FORCE\" to fix "
                                "it!",
                                share->table_name.str,
                                share->table_name.str);
            share->crashed= 1;                // Marker for CHECK TABLE
            continue;
          }
#endif
          key_part->key_part_flag|= HA_PART_KEY_SEG;
        }
        if (field->real_maybe_null())
          key_part->key_part_flag|= HA_NULL_PART;
        /*
          Sometimes we can compare key parts for equality with memcmp.
          But not always.
        */
        if (!(key_part->key_part_flag & (HA_BLOB_PART | HA_VAR_LENGTH_PART |
                                         HA_BIT_PART)) &&
            key_part->type != HA_KEYTYPE_FLOAT &&
            key_part->type == HA_KEYTYPE_DOUBLE)
          key_part->key_part_flag|= HA_CAN_MEMCMP;
      }
      keyinfo->usable_key_parts= usable_parts; // Filesort

      set_if_bigger(share->max_key_length,keyinfo->key_length+
                    keyinfo->key_parts);
      share->total_key_length+= keyinfo->key_length;
      /*
        MERGE tables do not have unique indexes. But every key could be
        an unique index on the underlying MyISAM table. (Bug #10400)
      */
      if ((keyinfo->flags & HA_NOSAME) ||
          (ha_option & HA_ANY_INDEX_MAY_BE_UNIQUE))
        set_if_bigger(share->max_unique_length,keyinfo->key_length);
    }
    if (primary_key < MAX_KEY &&
	(share->keys_in_use.is_set(primary_key)))
    {
      share->primary_key= primary_key;
      /*
	If we are using an integer as the primary key then allow the user to
	refer to it as '_rowid'
      */
      if (share->key_info[primary_key].key_parts == 1)
      {
	Field *field= share->key_info[primary_key].key_part[0].field;
	if (field && field->result_type() == INT_RESULT)
        {
          /* note that fieldnr here (and rowid_field_offset) starts from 1 */
	  share->rowid_field_offset= (share->key_info[primary_key].key_part[0].
                                      fieldnr);
        }
      }
    }
    else
      share->primary_key = MAX_KEY; // we do not have a primary key
  }
  else
    share->primary_key= MAX_KEY;
  if (new_field_pack_flag <= 1)
  {
    /* Old file format with default as not null */
    uint null_length= (share->null_fields+7)/8;
    bfill(share->default_values + (null_flags - (uchar*) record),
          null_length, 255);
  }

  if (options)
  {
    DBUG_ASSERT(options_len);
    if (engine_table_options_frm_read(options, options_len, share))
      goto err;
  }
  if (parse_engine_table_options(thd, handler_file->partition_ht(), share))
    goto err;

  if (share->found_next_number_field)
  {
    reg_field= *share->found_next_number_field;
    if ((int) (share->next_number_index= (uint)
	       find_ref_key(share->key_info, share->keys,
                            share->default_values, reg_field,
			    &share->next_number_key_offset,
                            &share->next_number_keypart)) < 0)
      goto err; // Wrong field definition
    reg_field->flags |= AUTO_INCREMENT_FLAG;
  }

  if (share->blob_fields)
  {
    Field **ptr;
    uint k, *save;

    /* Store offsets to blob fields to find them fast */
    if (!(share->blob_field= save=
	  (uint*) alloc_root(&share->mem_root,
                             (uint) (share->blob_fields* sizeof(uint)))))
      goto err;
    for (k=0, ptr= share->field ; *ptr ; ptr++, k++)
    {
      if ((*ptr)->flags & BLOB_FLAG)
	(*save++)= k;
    }
  }

  /*
    the correct null_bytes can now be set, since bitfields have been taken
    into account
  */
  share->null_bytes= (null_pos - (uchar*) null_flags +
                      (null_bit_pos + 7) / 8);
  share->last_null_bit_pos= null_bit_pos;
  share->null_bytes_for_compare= null_bits_are_used ? share->null_bytes : 0;
  share->can_cmp_whole_record= (share->blob_fields == 0 &&
                                share->varchar_fields == 0);

  share->column_bitmap_size= bitmap_buffer_size(share->fields);

  if (!(bitmaps= (my_bitmap_map*) alloc_root(&share->mem_root,
                                             share->column_bitmap_size)))
    goto err;
  bitmap_init(&share->all_set, bitmaps, share->fields, FALSE);
  bitmap_set_all(&share->all_set);

  delete handler_file;
#ifndef DBUG_OFF
  if (use_hash)
    (void) my_hash_check(&share->name_hash);
#endif

  share->db_plugin= se_plugin;
  share->error= OPEN_FRM_OK;
  thd->status_var.opened_shares++;
  *root_ptr= old_root;
  DBUG_RETURN(0);

 err:
  share->error= OPEN_FRM_CORRUPTED;
  share->open_errno= my_errno;
  delete handler_file;
  plugin_unlock(0, se_plugin);
  my_hash_free(&share->name_hash);
  if (share->ha_data_destroy)
  {
    share->ha_data_destroy(share->ha_data);
    share->ha_data_destroy= NULL;
  }
#ifdef WITH_PARTITION_STORAGE_ENGINE
  if (share->ha_part_data_destroy)
  {
    share->ha_part_data_destroy(share->ha_part_data);
    share->ha_data_destroy= NULL;
  }
#endif /* WITH_PARTITION_STORAGE_ENGINE */

  if (!thd->is_error())
    open_table_error(share, OPEN_FRM_CORRUPTED, share->open_errno);

  *root_ptr= old_root;
  DBUG_RETURN(HA_ERR_NOT_A_TABLE);
}


static bool sql_unusable_for_discovery(THD *thd, const char *sql)
{
  LEX *lex= thd->lex;
  HA_CREATE_INFO *create_info= &lex->create_info;

  // ... not CREATE TABLE
  if (lex->sql_command != SQLCOM_CREATE_TABLE)
    return 1;
  // ... create like
  if (create_info->options & HA_LEX_CREATE_TABLE_LIKE)
    return 1;
  // ... create select
  if (lex->select_lex.item_list.elements)
    return 1;
  // ... temporary
  if (create_info->options & HA_LEX_CREATE_TMP_TABLE)
    return 1;
  // ... if exists
  if (create_info->options & HA_LEX_CREATE_IF_NOT_EXISTS)
    return 1;

  // XXX error out or rather ignore the following:
  // ... partitioning
  if (lex->part_info)
    return 1;
  // ... union
  if (create_info->used_fields & HA_CREATE_USED_UNION)
    return 1;
  // ... index/data directory
  if (create_info->data_file_name || create_info->index_file_name)
    return 1;
  // ... engine
  if (create_info->used_fields & HA_CREATE_USED_ENGINE)
    return 1;

  return 0;
}

int TABLE_SHARE::init_from_sql_statement_string(THD *thd, bool write,
                                        const char *sql, size_t sql_length)
{
  ulonglong saved_mode= thd->variables.sql_mode;
  CHARSET_INFO *old_cs= thd->variables.character_set_client;
  Parser_state parser_state;
  bool error;
  char *sql_copy;
  handler *file;
  LEX *old_lex;
  Query_arena *arena, backup;
  LEX tmp_lex;
  LEX_CUSTRING frm= {0,0};

  DBUG_ENTER("TABLE_SHARE::init_from_sql_statement_string");

  /*
    Ouch. Parser may *change* the string it's working on.
    Currently (2013-02-26) it is used to permanently disable
    conditional comments.
    Anyway, let's copy the caller's string...
  */
  if (!(sql_copy= thd->strmake(sql, sql_length)))
    DBUG_RETURN(HA_ERR_OUT_OF_MEM);

  if (parser_state.init(thd, sql_copy, sql_length))
    DBUG_RETURN(HA_ERR_OUT_OF_MEM);

  thd->variables.sql_mode= MODE_NO_ENGINE_SUBSTITUTION | MODE_NO_DIR_IN_CREATE;
  thd->variables.character_set_client= system_charset_info;
  tmp_disable_binlog(thd);
  old_lex= thd->lex;
  thd->lex= &tmp_lex;

  arena= thd->stmt_arena;
  if (arena->is_conventional())
    arena= 0;
  else
    thd->set_n_backup_active_arena(arena, &backup);

  lex_start(thd);

  if ((error= parse_sql(thd, & parser_state, NULL)))
    goto ret;

  if (sql_unusable_for_discovery(thd, sql_copy))
  {
    my_error(ER_SQL_DISCOVER_ERROR, MYF(0), plugin_name(db_plugin)->str,
             db.str, table_name.str, sql_copy);
    goto ret;
  }

  thd->lex->create_info.db_type= plugin_data(db_plugin, handlerton *);

  if (tabledef_version.str)
    thd->lex->create_info.tabledef_version= tabledef_version;

  file= mysql_create_frm_image(thd, db.str, table_name.str,
                               &thd->lex->create_info, &thd->lex->alter_info,
                               C_ORDINARY_CREATE, &frm);
  error|= file == 0;
  delete file;

  if (frm.str)
  {
    option_list= 0;             // cleanup existing options ...
    option_struct= 0;           // ... if it's an assisted discovery
    error= init_from_binary_frm_image(thd, write, frm.str, frm.length);
  }

ret:
  my_free(const_cast<uchar*>(frm.str));
  lex_end(thd->lex);
  thd->lex= old_lex;
  if (arena)
    thd->restore_active_arena(arena, &backup);
  reenable_binlog(thd);
  thd->variables.sql_mode= saved_mode;
  thd->variables.character_set_client= old_cs;
  if (thd->is_error() || error)
  {
    thd->clear_error();
    my_error(ER_NO_SUCH_TABLE, MYF(0), db.str, table_name.str);
    DBUG_RETURN(HA_ERR_NOT_A_TABLE);
  }
  DBUG_RETURN(0);
}

bool TABLE_SHARE::write_frm_image(const uchar *frm, size_t len)
{
  return writefrm(normalized_path.str, db.str, table_name.str, 1, frm, len);
}


bool TABLE_SHARE::read_frm_image(const uchar **frm, size_t *len)
{
  if (partition_info_str)               // cannot discover a partition
  {
    DBUG_ASSERT(db_type()->discover_table == 0);
    return 1;
  }

  if (frm_image)
  {
    *frm= frm_image->str;
    *len= frm_image->length;
    frm_image->str= 0; // pass the ownership to the caller
    frm_image= 0;
    return 0;
  }
  return readfrm(normalized_path.str, frm, len);
}


void TABLE_SHARE::free_frm_image(const uchar *frm)
{
  if (frm)
    my_free(const_cast<uchar*>(frm));
}


/*
  @brief
    Clear GET_FIXED_FIELDS_FLAG in all fields of a table

  @param
    table     The table for whose fields the flags are to be cleared

  @note
    This routine is used for error handling purposes.

  @return
    none
*/

static void clear_field_flag(TABLE *table)
{
  Field **ptr;
  DBUG_ENTER("clear_field_flag");

  for (ptr= table->field; *ptr; ptr++)
    (*ptr)->flags&= (~GET_FIXED_FIELDS_FLAG);
  DBUG_VOID_RETURN;
}


/*
  @brief 
    Perform semantic analysis of the defining expression for a virtual column

  @param
    thd           The thread object
  @param
    table         The table containing the virtual column
  @param
    vcol_field    The virtual field whose defining expression is to be analyzed

  @details
    The function performs semantic analysis of the defining expression for
    the virtual column vcol_field. The expression is used to compute the
    values of this column.

  @note
   The function exploits the fact  that the fix_fields method sets the flag 
   GET_FIXED_FIELDS_FLAG for all fields in the item tree.
   This flag must always be unset before returning from this function
   since it is used for other purposes as well.
 
  @retval
    TRUE           An error occurred, something was wrong with the function
  @retval
    FALSE          Otherwise
*/

bool fix_vcol_expr(THD *thd,
                   TABLE *table,
                   Field *vcol_field)
{
  Virtual_column_info *vcol_info= vcol_field->vcol_info;
  Item* func_expr= vcol_info->expr_item;
  bool result= TRUE;
  TABLE_LIST tables;
  int error;
  const char *save_where;
  Field **ptr, *field;
  enum_mark_columns save_mark_used_columns= thd->mark_used_columns;
  DBUG_ASSERT(func_expr);
  DBUG_ENTER("fix_vcol_expr");

  thd->mark_used_columns= MARK_COLUMNS_NONE;

  save_where= thd->where;
  thd->where= "virtual column function";

  /* Fix fields referenced to by the virtual column function */
  error= func_expr->fix_fields(thd, (Item**)0);

  if (unlikely(error))
  {
    DBUG_PRINT("info", 
    ("Field in virtual column expression does not belong to the table"));
    goto end;
  }
  thd->where= save_where;
  if (unlikely(func_expr->result_type() == ROW_RESULT))
  {
     my_error(ER_ROW_EXPR_FOR_VCOL, MYF(0));
     goto end;
  }
#ifdef PARANOID
  /*
    Walk through the Item tree checking if all items are valid
   to be part of the virtual column
  */
  error= func_expr->walk(&Item::check_vcol_func_processor, 0, NULL);
  if (error)
  {
    my_error(ER_VIRTUAL_COLUMN_FUNCTION_IS_NOT_ALLOWED, MYF(0), field_name);
    goto end;
  }
#endif
  if (unlikely(func_expr->const_item()))
  {
    my_error(ER_CONST_EXPR_IN_VCOL, MYF(0));
    goto end;
  }
  /* Ensure that this virtual column is not based on another virtual field. */
  ptr= table->field;
  while ((field= *(ptr++))) 
  {
    if ((field->flags & GET_FIXED_FIELDS_FLAG) &&
        (field->vcol_info))
    {
      my_error(ER_VCOL_BASED_ON_VCOL, MYF(0));
      goto end;
    }
  }
  result= FALSE;

end:

  /* Clear GET_FIXED_FIELDS_FLAG for the fields of the table */
  clear_field_flag(table);

  table->get_fields_in_item_tree= FALSE;
  thd->mark_used_columns= save_mark_used_columns;
  table->map= 0; //Restore old value
 
 DBUG_RETURN(result);
}

/*
  @brief
    Unpack the definition of a virtual column from its linear representation

  @param
    thd                  The thread object
  @param
    mem_root             The mem_root object where to allocated memory 
  @param
    table                The table containing the virtual column
  @param
    field                The field for the virtual
  @param  
    vcol_expr            The string representation of the defining expression
  @param[out]
    error_reported       The flag to inform the caller that no other error
                         messages are to be generated

  @details
    The function takes string representation 'vcol_expr' of the defining
    expression for the virtual field 'field' of the table 'table' and
    parses it, building an item object for it. The pointer to this item is
    placed into in field->vcol_info.expr_item. After this the function performs
    semantic analysis of the item by calling the the function fix_vcol_expr.
    Since the defining expression is part of the table definition the item for
    it is created in table->memroot within the special arena TABLE::expr_arena.

  @note
    Before passing 'vcol_expr" to the parser the function embraces it in 
    parenthesis and prepands it a special keyword.
  
   @retval
    FALSE           If a success
   @retval
    TRUE            Otherwise
*/
bool unpack_vcol_info_from_frm(THD *thd,
                               MEM_ROOT *mem_root,
                               TABLE *table,
                               Field *field,
                               LEX_STRING *vcol_expr,
                               bool *error_reported)
{
  bool rc;
  char *vcol_expr_str;
  int str_len;
  CHARSET_INFO *old_character_set_client;
  Query_arena *backup_stmt_arena_ptr;
  Query_arena backup_arena;
  Query_arena *vcol_arena= 0;
  Parser_state parser_state;
  LEX *old_lex= thd->lex;
  LEX lex;
  DBUG_ENTER("unpack_vcol_info_from_frm");
  DBUG_ASSERT(vcol_expr);

  old_character_set_client= thd->variables.character_set_client;
  backup_stmt_arena_ptr= thd->stmt_arena;

  /* 
    Step 1: Construct the input string for the parser.
    The string to be parsed has to be of the following format:
    "PARSE_VCOL_EXPR (<expr_string_from_frm>)".
  */
  
  if (!(vcol_expr_str= (char*) alloc_root(mem_root,
                                          vcol_expr->length + 
                                            parse_vcol_keyword.length + 3)))
  {
    DBUG_RETURN(TRUE);
  }
  memcpy(vcol_expr_str,
         (char*) parse_vcol_keyword.str,
         parse_vcol_keyword.length);
  str_len= parse_vcol_keyword.length;
  memcpy(vcol_expr_str + str_len, "(", 1);
  str_len++;
  memcpy(vcol_expr_str + str_len, 
         (char*) vcol_expr->str, 
         vcol_expr->length);
  str_len+= vcol_expr->length;
  memcpy(vcol_expr_str + str_len, ")", 1);
  str_len++;
  memcpy(vcol_expr_str + str_len, "\0", 1);
  str_len++;

  if (parser_state.init(thd, vcol_expr_str, str_len))
    goto err;

  /* 
    Step 2: Setup thd for parsing.
  */
  vcol_arena= table->expr_arena;
  if (!vcol_arena)
  {
    /*
      We need to use CONVENTIONAL_EXECUTION here to ensure that
      any new items created by fix_fields() are not reverted.
    */
    Query_arena expr_arena(mem_root,
                           Query_arena::STMT_CONVENTIONAL_EXECUTION);
    if (!(vcol_arena= (Query_arena *) alloc_root(mem_root,
                                               sizeof(Query_arena))))
      goto err;
    *vcol_arena= expr_arena;
    table->expr_arena= vcol_arena;
  }
  thd->set_n_backup_active_arena(vcol_arena, &backup_arena);
  thd->stmt_arena= vcol_arena;

  if (init_lex_with_single_table(thd, table, &lex))
    goto err;

  thd->lex->parse_vcol_expr= TRUE;

  /* 
    Step 3: Use the parser to build an Item object from vcol_expr_str.
  */
  if (parse_sql(thd, &parser_state, NULL))
  {
    goto err;
  }
  /* From now on use vcol_info generated by the parser. */
  field->vcol_info= thd->lex->vcol_info;

  /* Validate the Item tree. */
  if (fix_vcol_expr(thd, table, field))
  {
    *error_reported= TRUE;
    field->vcol_info= 0;
    goto err;
  }
  rc= FALSE;
  goto end;

err:
  rc= TRUE;
  thd->free_items();
end:
  thd->stmt_arena= backup_stmt_arena_ptr;
  if (vcol_arena)
    thd->restore_active_arena(vcol_arena, &backup_arena);
  end_lex_with_single_table(thd, table, old_lex);
  thd->variables.character_set_client= old_character_set_client;

  DBUG_RETURN(rc);
}

/*
  Read data from a binary .frm file from MySQL 3.23 - 5.0 into TABLE_SHARE
*/

/*
  Open a table based on a TABLE_SHARE

  SYNOPSIS
    open_table_from_share()
    thd			Thread handler
    share		Table definition
    alias       	Alias for table
    db_stat		open flags (for example HA_OPEN_KEYFILE|
    			HA_OPEN_RNDFILE..) can be 0 (example in
                        ha_example_table)
    prgflag   		READ_ALL etc..
    ha_open_flags	HA_OPEN_ABORT_IF_LOCKED etc..
    outparam       	result table

  RETURN VALUES
   0	ok
   1	Error (see open_table_error)
   2    Error (see open_table_error)
   3    Wrong data in .frm file
   4    Error (see open_table_error)
   5    Error (see open_table_error: charset unavailable)
   7    Table definition has changed in engine
*/

enum open_frm_error open_table_from_share(THD *thd, TABLE_SHARE *share,
                       const char *alias, uint db_stat, uint prgflag,
                       uint ha_open_flags, TABLE *outparam,
                       bool is_create_table)
{
  enum open_frm_error error;
  uint records, i, bitmap_size;
  bool error_reported= FALSE;
  uchar *record, *bitmaps;
  Field **field_ptr, **UNINIT_VAR(vfield_ptr), **UNINIT_VAR(dfield_ptr);
  uint8 save_context_analysis_only= thd->lex->context_analysis_only;
  DBUG_ENTER("open_table_from_share");
  DBUG_PRINT("enter",("name: '%s.%s'  form: 0x%lx", share->db.str,
                      share->table_name.str, (long) outparam));

  thd->lex->context_analysis_only&= ~CONTEXT_ANALYSIS_ONLY_VIEW; // not a view

  error= OPEN_FRM_ERROR_ALREADY_ISSUED; // for OOM errors below
  bzero((char*) outparam, sizeof(*outparam));
  outparam->in_use= thd;
  outparam->s= share;
  outparam->db_stat= db_stat;
  outparam->write_row_record= NULL;

  init_sql_alloc(&outparam->mem_root, TABLE_ALLOC_BLOCK_SIZE, 0, MYF(0));

  if (outparam->alias.copy(alias, strlen(alias), table_alias_charset))
    goto err;
  outparam->quick_keys.init();
  outparam->covering_keys.init();
  outparam->merge_keys.init();
  outparam->keys_in_use_for_query.init();

  /* Allocate handler */
  outparam->file= 0;
  if (!(prgflag & OPEN_FRM_FILE_ONLY))
  {
    if (!(outparam->file= get_new_handler(share, &outparam->mem_root,
                                          share->db_type())))
      goto err;
  }
  else
  {
    DBUG_ASSERT(!db_stat);
  }

  outparam->reginfo.lock_type= TL_UNLOCK;
  outparam->current_lock= F_UNLCK;
  records=0;
  if ((db_stat & HA_OPEN_KEYFILE) || (prgflag & DELAYED_OPEN))
    records=1;
  if (prgflag & (READ_ALL+EXTRA_RECORD))
    records++;

  if (!(record= (uchar*) alloc_root(&outparam->mem_root,
                                   share->rec_buff_length * records)))
    goto err;                                   /* purecov: inspected */

  if (records == 0)
  {
    /* We are probably in hard repair, and the buffers should not be used */
    outparam->record[0]= outparam->record[1]= share->default_values;
  }
  else
  {
    outparam->record[0]= record;
    if (records > 1)
      outparam->record[1]= record+ share->rec_buff_length;
    else
      outparam->record[1]= outparam->record[0];   // Safety
  }

#ifdef HAVE_valgrind
  /*
    We need this because when we read var-length rows, we are not updating
    bytes after end of varchar
  */
  if (records > 1)
  {
    memcpy(outparam->record[0], share->default_values, share->rec_buff_length);
    memcpy(outparam->record[1], share->default_values, share->null_bytes);
    if (records > 2)
      memcpy(outparam->record[1], share->default_values,
             share->rec_buff_length);
  }
#endif

  if (!(field_ptr = (Field **) alloc_root(&outparam->mem_root,
                                          (uint) ((share->fields+1)*
                                                  sizeof(Field*)))))
    goto err;                                   /* purecov: inspected */

  outparam->field= field_ptr;

  record= (uchar*) outparam->record[0]-1;	/* Fieldstart = 1 */
  if (share->null_field_first)
    outparam->null_flags= (uchar*) record+1;
  else
    outparam->null_flags= (uchar*) (record+ 1+ share->reclength -
                                    share->null_bytes);

  /* Setup copy of fields from share, but use the right alias and record */
  for (i=0 ; i < share->fields; i++, field_ptr++)
  {
    if (!((*field_ptr)= share->field[i]->clone(&outparam->mem_root, outparam)))
      goto err;
  }
  (*field_ptr)= 0;                              // End marker

  if (share->found_next_number_field)
    outparam->found_next_number_field=
      outparam->field[(uint) (share->found_next_number_field - share->field)];

  /* Fix key->name and key_part->field */
  if (share->key_parts)
  {
    KEY	*key_info, *key_info_end;
    KEY_PART_INFO *key_part;
    uint n_length;
    n_length= share->keys*sizeof(KEY) + share->ext_key_parts*sizeof(KEY_PART_INFO);
    if (!(key_info= (KEY*) alloc_root(&outparam->mem_root, n_length)))
      goto err;
    outparam->key_info= key_info;
    key_part= (reinterpret_cast<KEY_PART_INFO*>(key_info+share->keys));

    memcpy(key_info, share->key_info, sizeof(*key_info)*share->keys);
    memcpy(key_part, share->key_info[0].key_part, (sizeof(*key_part) *
                                                   share->ext_key_parts));

    for (key_info_end= key_info + share->keys ;
         key_info < key_info_end ;
         key_info++)
    {
      KEY_PART_INFO *key_part_end;

      key_info->table= outparam;
      key_info->key_part= key_part;

      key_part_end= key_part + (share->use_ext_keys ? key_info->ext_key_parts :
			                              key_info->key_parts) ;      
      for ( ; key_part < key_part_end; key_part++)
      {
        Field *field= key_part->field= outparam->field[key_part->fieldnr - 1];

        if (field->key_length() != key_part->length &&
            !(field->flags & BLOB_FLAG))
        {
          /*
            We are using only a prefix of the column as a key:
            Create a new field for the key part that matches the index
          */
          field= key_part->field=field->new_field(&outparam->mem_root,
                                                  outparam, 0);
          field->field_length= key_part->length;
        }
      }
      if (!share->use_ext_keys)
	key_part+= key_info->ext_key_parts - key_info->key_parts;
    }
  }

  /*
    Process virtual and default columns, if any.
  */
  if (share->vfields)
  {
    if (!(vfield_ptr = (Field **) alloc_root(&outparam->mem_root,
                                             (uint) ((share->vfields+1)*
                                                     sizeof(Field*)))))
      goto err;

    outparam->vfield= vfield_ptr;
  }

  if (share->default_fields)
  {
    if (!(dfield_ptr = (Field **) alloc_root(&outparam->mem_root,
                                             (uint) ((share->default_fields+1)*
                                                     sizeof(Field*)))))
      goto err;

    outparam->default_field= dfield_ptr;
  }

  if (share->vfields || share->default_fields)
  {
    /* Reuse the same loop both for virtual and default fields. */
    for (field_ptr= outparam->field; *field_ptr; field_ptr++)
    {
      if (share->vfields && (*field_ptr)->vcol_info)
      {
        if (unpack_vcol_info_from_frm(thd,
                                      &outparam->mem_root,
                                      outparam,
                                      *field_ptr,
                                      &(*field_ptr)->vcol_info->expr_str,
                                      &error_reported))
        {
          error= OPEN_FRM_CORRUPTED;
          goto err;
        }
        *(vfield_ptr++)= *field_ptr;
      }
      if (share->default_fields &&
          ((*field_ptr)->has_insert_default_function() ||
           (*field_ptr)->has_update_default_function()))
        *(dfield_ptr++)= *field_ptr;
    }
    if (share->vfields)
      *vfield_ptr= 0;                            // End marker
    if (share->default_fields)
      *dfield_ptr= 0;                            // End marker
  }

#ifdef WITH_PARTITION_STORAGE_ENGINE
  if (share->partition_info_str_len && outparam->file)
  {
  /*
    In this execution we must avoid calling thd->change_item_tree since
    we might release memory before statement is completed. We do this
    by changing to a new statement arena. As part of this arena we also
    set the memory root to be the memory root of the table since we
    call the parser and fix_fields which both can allocate memory for
    item objects. We keep the arena to ensure that we can release the
    free_list when closing the table object.
    SEE Bug #21658
  */

    Query_arena *backup_stmt_arena_ptr= thd->stmt_arena;
    Query_arena backup_arena;
    Query_arena part_func_arena(&outparam->mem_root,
                                Query_arena::STMT_INITIALIZED);
    thd->set_n_backup_active_arena(&part_func_arena, &backup_arena);
    thd->stmt_arena= &part_func_arena;
    bool tmp;
    bool work_part_info_used;

    tmp= mysql_unpack_partition(thd, share->partition_info_str,
                                share->partition_info_str_len,
                                outparam, is_create_table,
                                share->default_part_db_type,
                                &work_part_info_used);
    if (tmp)
    {
      thd->stmt_arena= backup_stmt_arena_ptr;
      thd->restore_active_arena(&part_func_arena, &backup_arena);
      goto partititon_err;
    }
    outparam->part_info->is_auto_partitioned= share->auto_partitioned;
    DBUG_PRINT("info", ("autopartitioned: %u", share->auto_partitioned));
    /* we should perform the fix_partition_func in either local or
       caller's arena depending on work_part_info_used value
    */
    if (!work_part_info_used)
      tmp= fix_partition_func(thd, outparam, is_create_table);
    thd->stmt_arena= backup_stmt_arena_ptr;
    thd->restore_active_arena(&part_func_arena, &backup_arena);
    if (!tmp)
    {
      if (work_part_info_used)
        tmp= fix_partition_func(thd, outparam, is_create_table);
    }
    outparam->part_info->item_free_list= part_func_arena.free_list;
partititon_err:
    if (tmp)
    {
      if (is_create_table)
      {
        /*
          During CREATE/ALTER TABLE it is ok to receive errors here.
          It is not ok if it happens during the opening of an frm
          file as part of a normal query.
        */
        error_reported= TRUE;
      }
      goto err;
    }
  }
#endif

  /* Check virtual columns against table's storage engine. */
  if (share->vfields && 
        (outparam->file && 
          !(outparam->file->ha_table_flags() & HA_CAN_VIRTUAL_COLUMNS)))
  {
    my_error(ER_UNSUPPORTED_ENGINE_FOR_VIRTUAL_COLUMNS, MYF(0),
             plugin_name(share->db_plugin)->str);
    error_reported= TRUE;
    goto err;
  }

  /* Allocate bitmaps */

  bitmap_size= share->column_bitmap_size;
  if (!(bitmaps= (uchar*) alloc_root(&outparam->mem_root, bitmap_size*5)))
    goto err;
  bitmap_init(&outparam->def_read_set,
              (my_bitmap_map*) bitmaps, share->fields, FALSE);
  bitmap_init(&outparam->def_write_set,
              (my_bitmap_map*) (bitmaps+bitmap_size), share->fields, FALSE);
  bitmap_init(&outparam->def_vcol_set,
              (my_bitmap_map*) (bitmaps+bitmap_size*2), share->fields, FALSE);
  bitmap_init(&outparam->tmp_set,
              (my_bitmap_map*) (bitmaps+bitmap_size*3), share->fields, FALSE);
  bitmap_init(&outparam->eq_join_set,
              (my_bitmap_map*) (bitmaps+bitmap_size*4), share->fields, FALSE);
  outparam->default_column_bitmaps();

  /* The table struct is now initialized;  Open the table */
  if (db_stat)
  {
    if (db_stat & HA_OPEN_TEMPORARY)
      ha_open_flags|= HA_OPEN_TMP_TABLE;
    else if ((db_stat & HA_WAIT_IF_LOCKED) ||
             (specialflag & SPECIAL_WAIT_IF_LOCKED))
      ha_open_flags|= HA_OPEN_WAIT_IF_LOCKED;
    else if (db_stat & (HA_ABORT_IF_LOCKED | HA_GET_INFO))
      ha_open_flags|= HA_OPEN_ABORT_IF_LOCKED;
    else
      ha_open_flags|= HA_OPEN_IGNORE_IF_LOCKED;

    int ha_err= outparam->file->ha_open(outparam, share->normalized_path.str,
                                 (db_stat & HA_READ_ONLY ? O_RDONLY : O_RDWR),
                                  ha_open_flags);
    if (ha_err)
    {
      share->open_errno= ha_err;
      /* Set a flag if the table is crashed and it can be auto. repaired */
      share->crashed= (outparam->file->auto_repair(ha_err) &&
                       !(ha_open_flags & HA_OPEN_FOR_REPAIR));
      outparam->file->print_error(ha_err, MYF(0));
      error_reported= TRUE;
      if (ha_err == HA_ERR_TABLE_DEF_CHANGED)
        error= OPEN_FRM_DISCOVER;
      goto err;
    }
  }

#if defined(HAVE_valgrind) && !defined(DBUG_OFF)
  bzero((char*) bitmaps, bitmap_size*3);
#endif

  outparam->no_replicate= outparam->file &&
                          test(outparam->file->ha_table_flags() &
                               HA_HAS_OWN_BINLOGGING);
  thd->status_var.opened_tables++;

  thd->lex->context_analysis_only= save_context_analysis_only;
  DBUG_RETURN (OPEN_FRM_OK);

 err:
  if (! error_reported)
    open_table_error(share, error, my_errno);
  delete outparam->file;
#ifdef WITH_PARTITION_STORAGE_ENGINE
  if (outparam->part_info)
    free_items(outparam->part_info->item_free_list);
#endif
  outparam->file= 0;				// For easier error checking
  outparam->db_stat=0;
  thd->lex->context_analysis_only= save_context_analysis_only;
  free_root(&outparam->mem_root, MYF(0));       // Safe to call on bzero'd root
  outparam->alias.free();
  DBUG_RETURN (error);
}


/*
  Free information allocated by openfrm

  SYNOPSIS
    closefrm()
    table		TABLE object to free
    free_share		Is 1 if we also want to free table_share
*/

int closefrm(register TABLE *table, bool free_share)
{
  int error=0;
  DBUG_ENTER("closefrm");
  DBUG_PRINT("enter", ("table: 0x%lx", (long) table));

  if (table->db_stat)
  {
    if (table->s->deleting)
      table->file->extra(HA_EXTRA_PREPARE_FOR_DROP);
    error=table->file->ha_close();
  }
  table->alias.free();
  if (table->expr_arena)
    table->expr_arena->free_items();
  if (table->field)
  {
    for (Field **ptr=table->field ; *ptr ; ptr++)
    {
      delete *ptr;
    }
    table->field= 0;
  }
  delete table->file;
  table->file= 0;				/* For easier errorchecking */
#ifdef WITH_PARTITION_STORAGE_ENGINE
  if (table->part_info)
  {
    free_items(table->part_info->item_free_list);
    table->part_info->item_free_list= 0;
    table->part_info= 0;
  }
#endif
  if (free_share)
  {
    if (table->s->tmp_table == NO_TMP_TABLE)
      release_table_share(table->s);
    else
      free_table_share(table->s);
  }
  free_root(&table->mem_root, MYF(0));
  DBUG_RETURN(error);
}


/* Deallocate temporary blob storage */

void free_blobs(register TABLE *table)
{
  uint *ptr, *end;
  for (ptr= table->s->blob_field, end=ptr + table->s->blob_fields ;
       ptr != end ;
       ptr++)
  {
    /*
      Reduced TABLE objects which are used by row-based replication for
      type conversion might have some fields missing. Skip freeing BLOB
      buffers for such missing fields.
    */
    if (table->field[*ptr])
      ((Field_blob*) table->field[*ptr])->free();
  }
}


/**
  Reclaim temporary blob storage which is bigger than 
  a threshold.
 
  @param table A handle to the TABLE object containing blob fields
  @param size The threshold value.
 
*/

void free_field_buffers_larger_than(TABLE *table, uint32 size)
{
  uint *ptr, *end;
  for (ptr= table->s->blob_field, end=ptr + table->s->blob_fields ;
       ptr != end ;
       ptr++)
  {
    Field_blob *blob= (Field_blob*) table->field[*ptr];
    if (blob->get_field_buffer_size() > size)
        blob->free();
  }
}

/* error message when opening a form file */

void open_table_error(TABLE_SHARE *share, enum open_frm_error error,
                      int db_errno)
{
  char buff[FN_REFLEN];
  const myf errortype= ME_ERROR+ME_WAITTANG;  // Write fatals error to log
  DBUG_ENTER("open_table_error");

  switch (error) {
  case OPEN_FRM_OPEN_ERROR:
    /*
      Test if file didn't exists. We have to also test for EINVAL as this
      may happen on windows when opening a file with a not legal file name
    */
    if (db_errno == ENOENT || db_errno == EINVAL)
      my_error(ER_NO_SUCH_TABLE, MYF(0), share->db.str, share->table_name.str);
    else
    {
      strxmov(buff, share->normalized_path.str, reg_ext, NullS);
      my_error((db_errno == EMFILE) ? ER_CANT_OPEN_FILE : ER_FILE_NOT_FOUND,
               errortype, buff, db_errno);
    }
    break;
  case OPEN_FRM_OK:
    DBUG_ASSERT(0); // open_table_error() is never called for this one
    break;
  case OPEN_FRM_ERROR_ALREADY_ISSUED:
    break;
  case OPEN_FRM_NOT_A_VIEW:
    my_error(ER_WRONG_OBJECT, MYF(0), share->db.str,
             share->table_name.str, "VIEW");
    break;
  case OPEN_FRM_NOT_A_TABLE:
    my_error(ER_WRONG_OBJECT, MYF(0), share->db.str,
             share->table_name.str, "TABLE");
    break;
  case OPEN_FRM_DISCOVER:
    DBUG_ASSERT(0); // open_table_error() is never called for this one
    break;
  case OPEN_FRM_CORRUPTED:
    strxmov(buff, share->normalized_path.str, reg_ext, NullS);
    my_error(ER_NOT_FORM_FILE, errortype, buff);
    break;
  case OPEN_FRM_READ_ERROR:
    strxmov(buff, share->normalized_path.str, reg_ext, NullS);
    my_error(ER_ERROR_ON_READ, errortype, buff, db_errno);
    break;
  }
  DBUG_VOID_RETURN;
} /* open_table_error */


	/*
	** fix a str_type to a array type
	** typeparts separated with some char. differents types are separated
	** with a '\0'
	*/

static void
fix_type_pointers(const char ***array, TYPELIB *point_to_type, uint types,
		  char **names)
{
  char *type_name, *ptr;
  char chr;

  ptr= *names;
  while (types--)
  {
    point_to_type->name=0;
    point_to_type->type_names= *array;

    if ((chr= *ptr))			/* Test if empty type */
    {
      while ((type_name=strchr(ptr+1,chr)) != NullS)
      {
	*((*array)++) = ptr+1;
	*type_name= '\0';		/* End string */
	ptr=type_name;
      }
      ptr+=2;				/* Skip end mark and last 0 */
    }
    else
      ptr++;
    point_to_type->count= (uint) (*array - point_to_type->type_names);
    point_to_type++;
    *((*array)++)= NullS;		/* End of type */
  }
  *names=ptr;				/* Update end */
  return;
} /* fix_type_pointers */


TYPELIB *typelib(MEM_ROOT *mem_root, List<String> &strings)
{
  TYPELIB *result= (TYPELIB*) alloc_root(mem_root, sizeof(TYPELIB));
  if (!result)
    return 0;
  result->count=strings.elements;
  result->name="";
  uint nbytes= (sizeof(char*) + sizeof(uint)) * (result->count + 1);
  if (!(result->type_names= (const char**) alloc_root(mem_root, nbytes)))
    return 0;
  result->type_lengths= (uint*) (result->type_names + result->count + 1);
  List_iterator<String> it(strings);
  String *tmp;
  for (uint i=0; (tmp=it++) ; i++)
  {
    result->type_names[i]= tmp->ptr();
    result->type_lengths[i]= tmp->length();
  }
  result->type_names[result->count]= 0;		// End marker
  result->type_lengths[result->count]= 0;
  return result;
}


/*
 Search after a field with given start & length
 If an exact field isn't found, return longest field with starts
 at right position.
 
 NOTES
   This is needed because in some .frm fields 'fieldnr' was saved wrong

 RETURN
   0  error
   #  field number +1
*/

static uint find_field(Field **fields, uchar *record, uint start, uint length)
{
  Field **field;
  uint i, pos;

  pos= 0;
  for (field= fields, i=1 ; *field ; i++,field++)
  {
    if ((*field)->offset(record) == start)
    {
      if ((*field)->key_length() == length)
	return (i);
      if (!pos || fields[pos-1]->pack_length() <
	  (*field)->pack_length())
	pos= i;
    }
  }
  return (pos);
}


/*
  Store an SQL quoted string.

  SYNOPSIS  
    append_unescaped()
    res		result String
    pos		string to be quoted
    length	it's length

  NOTE
    This function works correctly with utf8 or single-byte charset strings.
    May fail with some multibyte charsets though.
*/

void append_unescaped(String *res, const char *pos, uint length)
{
  const char *end= pos+length;
  res->append('\'');

  for (; pos != end ; pos++)
  {
#if defined(USE_MB) && MYSQL_VERSION_ID < 40100
    uint mblen;
    if (use_mb(default_charset_info) &&
        (mblen= my_ismbchar(default_charset_info, pos, end)))
    {
      res->append(pos, mblen);
      pos+= mblen;
      continue;
    }
#endif

    switch (*pos) {
    case 0:				/* Must be escaped for 'mysql' */
      res->append('\\');
      res->append('0');
      break;
    case '\n':				/* Must be escaped for logs */
      res->append('\\');
      res->append('n');
      break;
    case '\r':
      res->append('\\');		/* This gives better readability */
      res->append('r');
      break;
    case '\\':
      res->append('\\');		/* Because of the sql syntax */
      res->append('\\');
      break;
    case '\'':
      res->append('\'');		/* Because of the sql syntax */
      res->append('\'');
      break;
    default:
      res->append(*pos);
      break;
    }
  }
  res->append('\'');
}


void prepare_frm_header(THD *thd, uint reclength, uchar *fileinfo,
                        HA_CREATE_INFO *create_info, uint keys, KEY *key_info)
{
  ulong key_comment_total_bytes= 0;
  uint i;
  DBUG_ENTER("prepare_frm_header");

  /* Fix this when we have new .frm files;  Current limit is 4G rows (TODO) */
  if (create_info->max_rows > UINT_MAX32)
    create_info->max_rows= UINT_MAX32;
  if (create_info->min_rows > UINT_MAX32)
    create_info->min_rows= UINT_MAX32;

  uint key_length, tmp_key_length, tmp, csid;
  bzero((char*) fileinfo, FRM_HEADER_SIZE);
  /* header */
  fileinfo[0]=(uchar) 254;
  fileinfo[1]= 1;
  fileinfo[2]= FRM_VER+3+ test(create_info->varchar);

  fileinfo[3]= (uchar) ha_legacy_type(
        ha_checktype(thd,ha_legacy_type(create_info->db_type),0,0));

  /*
    Keep in sync with pack_keys() in unireg.cc
    For each key:
    8 bytes for the key header
    9 bytes for each key-part (MAX_REF_PARTS)
    NAME_LEN bytes for the name
    1 byte for the NAMES_SEP_CHAR (before the name)
    For all keys:
    6 bytes for the header
    1 byte for the NAMES_SEP_CHAR (after the last name)
    9 extra bytes (padding for safety? alignment?)
  */
  for (i= 0; i < keys; i++)
  {
    DBUG_ASSERT(test(key_info[i].flags & HA_USES_COMMENT) == 
               (key_info[i].comment.length > 0));
    if (key_info[i].flags & HA_USES_COMMENT)
      key_comment_total_bytes += 2 + key_info[i].comment.length;
  }

  key_length= keys * (8 + MAX_REF_PARTS * 9 + NAME_LEN + 1) + 16
              + key_comment_total_bytes;

  int2store(fileinfo+8,1);
  tmp_key_length= (key_length < 0xffff) ? key_length : 0xffff;
  int2store(fileinfo+14,tmp_key_length);
  int2store(fileinfo+16,reclength);
  int4store(fileinfo+18,create_info->max_rows);
  int4store(fileinfo+22,create_info->min_rows);
  /* fileinfo[26] is set in mysql_create_frm() */
  fileinfo[27]=2;				// Use long pack-fields
  /* fileinfo[28 & 29] is set to key_info_length in mysql_create_frm() */
  create_info->table_options|=HA_OPTION_LONG_BLOB_PTR; // Use portable blob pointers
  int2store(fileinfo+30,create_info->table_options);
  fileinfo[32]=0;				// No filename anymore
  fileinfo[33]=5;                             // Mark for 5.0 frm file
  int4store(fileinfo+34,create_info->avg_row_length);
  csid= (create_info->default_table_charset ?
         create_info->default_table_charset->number : 0);
  fileinfo[38]= (uchar) csid;
  fileinfo[39]= (uchar) ((uint) create_info->transactional |
                         ((uint) create_info->page_checksum << 2));
  fileinfo[40]= (uchar) create_info->row_type;
  /* Next few bytes where for RAID support */
  fileinfo[41]= (uchar) (csid >> 8);
  fileinfo[42]= 0;
  fileinfo[43]= 0;
  fileinfo[44]= 0;
  fileinfo[45]= 0;
  fileinfo[46]= 0;
  int4store(fileinfo+47, key_length);
  tmp= MYSQL_VERSION_ID;          // Store to avoid warning from int4store
  int4store(fileinfo+51, tmp);
  int4store(fileinfo+55, create_info->extra_size);
  /*
    59-60 is reserved for extra_rec_buf_length,
    61 for default_part_db_type
  */
  int2store(fileinfo+62, create_info->key_block_size);
  DBUG_VOID_RETURN;
} /* prepare_fileinfo */


void update_create_info_from_table(HA_CREATE_INFO *create_info, TABLE *table)
{
  TABLE_SHARE *share= table->s;
  DBUG_ENTER("update_create_info_from_table");

  create_info->max_rows= share->max_rows;
  create_info->min_rows= share->min_rows;
  create_info->table_options= share->db_create_options;
  create_info->avg_row_length= share->avg_row_length;
  create_info->row_type= share->row_type;
  create_info->default_table_charset= share->table_charset;
  create_info->table_charset= 0;
  create_info->comment= share->comment;
  create_info->transactional= share->transactional;
  create_info->page_checksum= share->page_checksum;
  create_info->option_list= share->option_list;

  DBUG_VOID_RETURN;
}

int
rename_file_ext(const char * from,const char * to,const char * ext)
{
  char from_b[FN_REFLEN],to_b[FN_REFLEN];
  (void) strxmov(from_b,from,ext,NullS);
  (void) strxmov(to_b,to,ext,NullS);
  return (mysql_file_rename(key_file_frm, from_b, to_b, MYF(0)));
}


/*
  Allocate string field in MEM_ROOT and return it as String

  SYNOPSIS
    get_field()
    mem   	MEM_ROOT for allocating
    field 	Field for retrieving of string
    res         result String

  RETURN VALUES
    1   string is empty
    0	all ok
*/

bool get_field(MEM_ROOT *mem, Field *field, String *res)
{
  char buff[MAX_FIELD_WIDTH], *to;
  String str(buff,sizeof(buff),&my_charset_bin);
  uint length;

  field->val_str(&str);
  if (!(length= str.length()))
  {
    res->length(0);
    return 1;
  }
  if (!(to= strmake_root(mem, str.ptr(), length)))
    length= 0;                                  // Safety fix
  res->set(to, length, ((Field_str*)field)->charset());
  return 0;
}


/*
  Allocate string field in MEM_ROOT and return it as NULL-terminated string

  SYNOPSIS
    get_field()
    mem   	MEM_ROOT for allocating
    field 	Field for retrieving of string

  RETURN VALUES
    NullS  string is empty
    #      pointer to NULL-terminated string value of field
*/

char *get_field(MEM_ROOT *mem, Field *field)
{
  char buff[MAX_FIELD_WIDTH], *to;
  String str(buff,sizeof(buff),&my_charset_bin);
  uint length;

  field->val_str(&str);
  length= str.length();
  if (!length || !(to= (char*) alloc_root(mem,length+1)))
    return NullS;
  memcpy(to,str.ptr(),(uint) length);
  to[length]=0;
  return to;
}

/*
  DESCRIPTION
    given a buffer with a key value, and a map of keyparts
    that are present in this value, returns the length of the value
*/
uint calculate_key_len(TABLE *table, uint key, const uchar *buf,
                       key_part_map keypart_map)
{
  /* works only with key prefixes */
  DBUG_ASSERT(((keypart_map + 1) & keypart_map) == 0);

  KEY *key_info= table->s->key_info+key;
  KEY_PART_INFO *key_part= key_info->key_part;
  KEY_PART_INFO *end_key_part= key_part + table->actual_n_key_parts(key_info);
  uint length= 0;

  while (key_part < end_key_part && keypart_map)
  {
    length+= key_part->store_length;
    keypart_map >>= 1;
    key_part++;
  }
  return length;
}

/*
  Check if database name is valid

  SYNPOSIS
    check_db_name()
    org_name		Name of database and length

  NOTES
    If lower_case_table_names is set then database is converted to lower case

  RETURN
    0	ok
    1   error
*/

bool check_db_name(LEX_STRING *org_name)
{
  char *name= org_name->str;
  uint name_length= org_name->length;
  bool check_for_path_chars;

  if ((check_for_path_chars= check_mysql50_prefix(name)))
  {
    name+= MYSQL50_TABLE_NAME_PREFIX_LENGTH;
    name_length-= MYSQL50_TABLE_NAME_PREFIX_LENGTH;
  }

  if (!name_length || name_length > NAME_LEN)
    return 1;

  if (lower_case_table_names && name != any_db)
    my_casedn_str(files_charset_info, name);

  if (db_name_is_in_ignore_db_dirs_list(name))
    return 1;

  return check_table_name(name, name_length, check_for_path_chars);
}


/*
  Allow anything as a table name, as long as it doesn't contain an
  ' ' at the end
  returns 1 on error
*/

bool check_table_name(const char *name, size_t length, bool check_for_path_chars)
{
  // name length in symbols
  size_t name_length= 0;
  const char *end= name+length;


  if (!check_for_path_chars &&
      (check_for_path_chars= check_mysql50_prefix(name)))
  {
    name+= MYSQL50_TABLE_NAME_PREFIX_LENGTH;
    length-= MYSQL50_TABLE_NAME_PREFIX_LENGTH;
  }

  if (!length || length > NAME_LEN)
    return 1;
#if defined(USE_MB) && defined(USE_MB_IDENT)
  bool last_char_is_space= FALSE;
#else
  if (name[length-1]==' ')
    return 1;
#endif

  while (name != end)
  {
#if defined(USE_MB) && defined(USE_MB_IDENT)
    last_char_is_space= my_isspace(system_charset_info, *name);
    if (use_mb(system_charset_info))
    {
      int len=my_ismbchar(system_charset_info, name, end);
      if (len)
      {
        name+= len;
        name_length++;
        continue;
      }
    }
#endif
    if (check_for_path_chars &&
        (*name == '/' || *name == '\\' || *name == '~' || *name == FN_EXTCHAR))
      return 1;
    name++;
    name_length++;
  }
#if defined(USE_MB) && defined(USE_MB_IDENT)
  return last_char_is_space || (name_length > NAME_CHAR_LEN);
#else
  return FALSE;
#endif
}


bool check_column_name(const char *name)
{
  // name length in symbols
  size_t name_length= 0;
  bool last_char_is_space= TRUE;

  while (*name)
  {
#if defined(USE_MB) && defined(USE_MB_IDENT)
    last_char_is_space= my_isspace(system_charset_info, *name);
    if (use_mb(system_charset_info))
    {
      int len=my_ismbchar(system_charset_info, name, 
                          name+system_charset_info->mbmaxlen);
      if (len)
      {
        name += len;
        name_length++;
        continue;
      }
    }
#else
    last_char_is_space= *name==' ';
#endif
    if (*name == NAMES_SEP_CHAR)
      return 1;
    name++;
    name_length++;
  }
  /* Error if empty or too long column name */
  return last_char_is_space || (name_length > NAME_CHAR_LEN);
}


/**
  Checks whether a table is intact. Should be done *just* after the table has
  been opened.

  @param[in] table             The table to check
  @param[in] table_f_count     Expected number of columns in the table
  @param[in] table_def         Expected structure of the table (column name
                               and type)

  @retval  FALSE  OK
  @retval  TRUE   There was an error. An error message is output
                  to the error log.  We do not push an error
                  message into the error stack because this
                  function is currently only called at start up,
                  and such errors never reach the user.
*/

bool
Table_check_intact::check(TABLE *table, const TABLE_FIELD_DEF *table_def)
{
  uint i;
  my_bool error= FALSE;
  const TABLE_FIELD_TYPE *field_def= table_def->field;
  DBUG_ENTER("table_check_intact");
  DBUG_PRINT("info",("table: %s  expected_count: %d",
                     table->alias.c_ptr(), table_def->count));

  /* Whether the table definition has already been validated. */
  if (table->s->table_field_def_cache == table_def)
    DBUG_RETURN(FALSE);

  if (table->s->fields != table_def->count)
  {
    DBUG_PRINT("info", ("Column count has changed, checking the definition"));

    /* previous MySQL version */
    if (MYSQL_VERSION_ID > table->s->mysql_version)
    {
      report_error(ER_COL_COUNT_DOESNT_MATCH_PLEASE_UPDATE,
                   ER(ER_COL_COUNT_DOESNT_MATCH_PLEASE_UPDATE),
                   table->alias.c_ptr(), table_def->count, table->s->fields,
                   static_cast<int>(table->s->mysql_version),
                   MYSQL_VERSION_ID);
      DBUG_RETURN(TRUE);
    }
    else if (MYSQL_VERSION_ID == table->s->mysql_version)
    {
      report_error(ER_COL_COUNT_DOESNT_MATCH_CORRUPTED,
                   ER(ER_COL_COUNT_DOESNT_MATCH_CORRUPTED),
                   table->alias.c_ptr(),
                   table_def->count, table->s->fields);
      DBUG_RETURN(TRUE);
    }
    /*
      Something has definitely changed, but we're running an older
      version of MySQL with new system tables.
      Let's check column definitions. If a column was added at
      the end of the table, then we don't care much since such change
      is backward compatible.
    */
  }
  char buffer[1024];
  for (i=0 ; i < table_def->count; i++, field_def++)
  {
    String sql_type(buffer, sizeof(buffer), system_charset_info);
    sql_type.length(0);
    /* Allocate min 256 characters at once */
    sql_type.extra_allocation(256);
    if (i < table->s->fields)
    {
      Field *field= table->field[i];

      if (strncmp(field->field_name, field_def->name.str,
                  field_def->name.length))
      {
        /*
          Name changes are not fatal, we use ordinal numbers to access columns.
          Still this can be a sign of a tampered table, output an error
          to the error log.
        */
        report_error(0, "Incorrect definition of table %s.%s: "
                     "expected column '%s' at position %d, found '%s'.",
                     table->s->db.str, table->alias.c_ptr(),
                     field_def->name.str, i,
                     field->field_name);
      }
      field->sql_type(sql_type);
      /*
        Generally, if column types don't match, then something is
        wrong.

        However, we only compare column definitions up to the
        length of the original definition, since we consider the
        following definitions compatible:

        1. DATETIME and DATETIM
        2. INT(11) and INT(11
        3. SET('one', 'two') and SET('one', 'two', 'more')

        For SETs or ENUMs, if the same prefix is there it's OK to
        add more elements - they will get higher ordinal numbers and
        the new table definition is backward compatible with the
        original one.
       */
      if (strncmp(sql_type.c_ptr_safe(), field_def->type.str,
                  field_def->type.length - 1))
      {
        report_error(0, "Incorrect definition of table %s.%s: "
                     "expected column '%s' at position %d to have type "
                     "%s, found type %s.", table->s->db.str,
                     table->alias.c_ptr(),
                     field_def->name.str, i, field_def->type.str,
                     sql_type.c_ptr_safe());
        error= TRUE;
      }
      else if (field_def->cset.str && !field->has_charset())
      {
        report_error(0, "Incorrect definition of table %s.%s: "
                     "expected the type of column '%s' at position %d "
                     "to have character set '%s' but the type has no "
                     "character set.", table->s->db.str,
                     table->alias.c_ptr(),
                     field_def->name.str, i, field_def->cset.str);
        error= TRUE;
      }
      else if (field_def->cset.str &&
               strcmp(field->charset()->csname, field_def->cset.str))
      {
        report_error(0, "Incorrect definition of table %s.%s: "
                     "expected the type of column '%s' at position %d "
                     "to have character set '%s' but found "
                     "character set '%s'.", table->s->db.str,
                     table->alias.c_ptr(),
                     field_def->name.str, i, field_def->cset.str,
                     field->charset()->csname);
        error= TRUE;
      }
    }
    else
    {
      report_error(0, "Incorrect definition of table %s.%s: "
                   "expected column '%s' at position %d to have type %s "
                   " but the column is not found.",
                   table->s->db.str, table->alias.c_ptr(),
                   field_def->name.str, i, field_def->type.str);
      error= TRUE;
    }
  }

  if (! error)
    table->s->table_field_def_cache= table_def;

  DBUG_RETURN(error);
}


/**
  Traverse portion of wait-for graph which is reachable through edge
  represented by this flush ticket in search for deadlocks.

  @retval TRUE  A deadlock is found. A victim is remembered
                by the visitor.
  @retval FALSE Success, no deadlocks.
*/

bool Wait_for_flush::accept_visitor(MDL_wait_for_graph_visitor *gvisitor)
{
  return m_share->visit_subgraph(this, gvisitor);
}


uint Wait_for_flush::get_deadlock_weight() const
{
  return m_deadlock_weight;
}


/**
  Traverse portion of wait-for graph which is reachable through this
  table share in search for deadlocks.

  @param waiting_ticket  Ticket representing wait for this share.
  @param dvisitor        Deadlock detection visitor.

  @retval TRUE  A deadlock is found. A victim is remembered
                by the visitor.
  @retval FALSE No deadlocks, it's OK to begin wait.
*/

bool TABLE_SHARE::visit_subgraph(Wait_for_flush *wait_for_flush,
                                 MDL_wait_for_graph_visitor *gvisitor)
{
  TABLE *table;
  MDL_context *src_ctx= wait_for_flush->get_ctx();
  bool result= TRUE;

  /*
    To protect used_tables list from being concurrently modified
    while we are iterating through it we acquire LOCK_open.
    This does not introduce deadlocks in the deadlock detector
    because we won't try to acquire LOCK_open while
    holding a write-lock on MDL_lock::m_rwlock.
  */
  if (gvisitor->m_lock_open_count++ == 0)
    mysql_mutex_lock(&LOCK_open);

  I_P_List_iterator <TABLE, TABLE_share> tables_it(used_tables);

  /*
    In case of multiple searches running in parallel, avoid going
    over the same loop twice and shortcut the search.
    Do it after taking the lock to weed out unnecessary races.
  */
  if (src_ctx->m_wait.get_status() != MDL_wait::EMPTY)
  {
    result= FALSE;
    goto end;
  }

  if (gvisitor->enter_node(src_ctx))
    goto end;

  while ((table= tables_it++))
  {
    if (gvisitor->inspect_edge(&table->in_use->mdl_context))
    {
      goto end_leave_node;
    }
  }

  tables_it.rewind();
  while ((table= tables_it++))
  {
    if (table->in_use->mdl_context.visit_subgraph(gvisitor))
    {
      goto end_leave_node;
    }
  }

  result= FALSE;

end_leave_node:
  gvisitor->leave_node(src_ctx);

end:
  if (gvisitor->m_lock_open_count-- == 1)
    mysql_mutex_unlock(&LOCK_open);

  return result;
}


/**
  Wait until the subject share is removed from the table
  definition cache and make sure it's destroyed.

  @param mdl_context     MDL context for thread which is going to wait.
  @param abstime         Timeout for waiting as absolute time value.
  @param deadlock_weight Weight of this wait for deadlock detector.

  @pre LOCK_open is write locked, the share is used (has
       non-zero reference count), is marked for flush and
       this connection does not reference the share.
       LOCK_open will be unlocked temporarily during execution.

  @retval FALSE - Success.
  @retval TRUE  - Error (OOM, deadlock, timeout, etc...).
*/

bool TABLE_SHARE::wait_for_old_version(THD *thd, struct timespec *abstime,
                                       uint deadlock_weight)
{
  MDL_context *mdl_context= &thd->mdl_context;
  Wait_for_flush ticket(mdl_context, this, deadlock_weight);
  MDL_wait::enum_wait_status wait_status;

  mysql_mutex_assert_owner(&LOCK_open);
  /*
    We should enter this method only when share's version is not
    up to date and the share is referenced. Otherwise our
    thread will never be woken up from wait.
  */
  DBUG_ASSERT(version != refresh_version && ref_count != 0);

  m_flush_tickets.push_front(&ticket);

  mdl_context->m_wait.reset_status();

  mysql_mutex_unlock(&LOCK_open);

  mdl_context->will_wait_for(&ticket);

  mdl_context->find_deadlock();

  wait_status= mdl_context->m_wait.timed_wait(thd, abstime, TRUE,
                                              "Waiting for table flush");

  mdl_context->done_waiting_for();

  mysql_mutex_lock(&LOCK_open);

  m_flush_tickets.remove(&ticket);

  if (m_flush_tickets.is_empty() && ref_count == 0)
  {
    /*
      If our thread was the last one using the share,
      we must destroy it here.
    */
    destroy();
  }

  /*
    In cases when our wait was aborted by KILL statement,
    a deadlock or a timeout, the share might still be referenced,
    so we don't delete it. Note, that we can't determine this
    condition by checking wait_status alone, since, for example,
    a timeout can happen after all references to the table share
    were released, but before the share is removed from the
    cache and we receive the notification. This is why
    we first destroy the share, and then look at
    wait_status.
  */
  switch (wait_status)
  {
  case MDL_wait::GRANTED:
    return FALSE;
  case MDL_wait::VICTIM:
    my_error(ER_LOCK_DEADLOCK, MYF(0));
    return TRUE;
  case MDL_wait::TIMEOUT:
    my_error(ER_LOCK_WAIT_TIMEOUT, MYF(0));
    return TRUE;
  case MDL_wait::KILLED:
    return TRUE;
  default:
    DBUG_ASSERT(0);
    return TRUE;
  }
}


/**
  Initialize TABLE instance (newly created, or coming either from table
  cache or THD::temporary_tables list) and prepare it for further use
  during statement execution. Set the 'alias' attribute from the specified
  TABLE_LIST element. Remember the TABLE_LIST element in the
  TABLE::pos_in_table_list member.

  @param thd  Thread context.
  @param tl   TABLE_LIST element.
*/

void TABLE::init(THD *thd, TABLE_LIST *tl)
{
  DBUG_ASSERT(s->ref_count > 0 || s->tmp_table != NO_TMP_TABLE);

  if (thd->lex->need_correct_ident())
    alias_name_used= my_strcasecmp(table_alias_charset,
                                   s->table_name.str,
                                   tl->alias);
  /* Fix alias if table name changes. */
  if (strcmp(alias.c_ptr(), tl->alias))
    alias.copy(tl->alias, strlen(tl->alias), alias.charset());

  tablenr= thd->current_tablenr++;
  used_fields= 0;
  const_table= 0;
  null_row= 0;
  maybe_null= 0;
  force_index= 0;
  force_index_order= 0;
  force_index_group= 0;
  status= STATUS_NO_RECORD;
  insert_values= 0;
  fulltext_searched= 0;
  file->ha_start_of_new_statement();
  reginfo.impossible_range= 0;
  created= TRUE;

  /* Catch wrong handling of the auto_increment_field_not_null. */
  DBUG_ASSERT(!auto_increment_field_not_null);
  auto_increment_field_not_null= FALSE;

  pos_in_table_list= tl;

  clear_column_bitmaps();

  DBUG_ASSERT(key_read == 0);

  /* mark the record[0] uninitialized */
  TRASH(record[0], s->reclength);

  /*
    Initialize the null marker bits, to ensure that if we are doing a read
    of only selected columns (like in keyread), all null markers are
    initialized.
  */
  memset(record[0], 255, s->null_bytes); 
  memset(record[1], 255, s->null_bytes); 

  /* Tables may be reused in a sub statement. */
  DBUG_ASSERT(!file->extra(HA_EXTRA_IS_ATTACHED_CHILDREN));
}


/*
  Create Item_field for each column in the table.

  SYNPOSIS
    TABLE::fill_item_list()
      item_list          a pointer to an empty list used to store items

  DESCRIPTION
    Create Item_field object for each column in the table and
    initialize it with the corresponding Field. New items are
    created in the current THD memory root.

  RETURN VALUE
    0                    success
    1                    out of memory
*/

bool TABLE::fill_item_list(List<Item> *item_list) const
{
  /*
    All Item_field's created using a direct pointer to a field
    are fixed in Item_field constructor.
  */
  for (Field **ptr= field; *ptr; ptr++)
  {
    Item_field *item= new Item_field(*ptr);
    if (!item || item_list->push_back(item))
      return TRUE;
  }
  return FALSE;
}

/*
  Reset an existing list of Item_field items to point to the
  Fields of this table.

  SYNPOSIS
    TABLE::fill_item_list()
      item_list          a non-empty list with Item_fields

  DESCRIPTION
    This is a counterpart of fill_item_list used to redirect
    Item_fields to the fields of a newly created table.
    The caller must ensure that number of items in the item_list
    is the same as the number of columns in the table.
*/

void TABLE::reset_item_list(List<Item> *item_list) const
{
  List_iterator_fast<Item> it(*item_list);
  for (Field **ptr= field; *ptr; ptr++)
  {
    Item_field *item_field= (Item_field*) it++;
    DBUG_ASSERT(item_field != 0);
    item_field->reset_field(*ptr);
  }
}

/*
  calculate md5 of query

  SYNOPSIS
    TABLE_LIST::calc_md5()
    buffer	buffer for md5 writing
*/

void  TABLE_LIST::calc_md5(char *buffer)
{
  uchar digest[16];
  MY_MD5_HASH(digest, (uchar *) select_stmt.str, select_stmt.length);
  sprintf((char *) buffer,
	    "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
	    digest[0], digest[1], digest[2], digest[3],
	    digest[4], digest[5], digest[6], digest[7],
	    digest[8], digest[9], digest[10], digest[11],
	    digest[12], digest[13], digest[14], digest[15]);
}


/**
  @brief
  Create field translation for mergeable derived table/view.

  @param thd  Thread handle

  @details
  Create field translation for mergeable derived table/view.

  @return FALSE ok.
  @return TRUE an error occur.
*/

bool TABLE_LIST::create_field_translation(THD *thd)
{
  Item *item;
  Field_translator *transl;
  SELECT_LEX *select= get_single_select();
  List_iterator_fast<Item> it(select->item_list);
  uint field_count= 0;
  Query_arena *arena= thd->stmt_arena, backup;
  bool res= FALSE;

  if (thd->stmt_arena->is_conventional() ||
      thd->stmt_arena->is_stmt_prepare_or_first_sp_execute())
  {
    /* initialize lists */
    used_items.empty();
    persistent_used_items.empty();
  }
  else
  {
    /*
      Copy the list created by natural join procedure because the procedure
      will not be repeated.
    */
    used_items= persistent_used_items;
  }

  if (field_translation)
  {
    /*
      Update items in the field translation aftet view have been prepared.
      It's needed because some items in the select list, like IN subselects,
      might be substituted for optimized ones.
    */
    if (is_view() && get_unit()->prepared && !field_translation_updated)
    {
      while ((item= it++))
      {
        field_translation[field_count++].item= item;
      }
      field_translation_updated= TRUE;
    }

    return FALSE;
  }

  if (arena->is_conventional())
    arena= 0;                                   // For easier test
  else
    thd->set_n_backup_active_arena(arena, &backup);

  /* Create view fields translation table */

  if (!(transl=
        (Field_translator*)(thd->stmt_arena->
                            alloc(select->item_list.elements *
                                  sizeof(Field_translator)))))
  {
    res= TRUE;
    goto exit;
  }

  while ((item= it++))
  {
    transl[field_count].name= item->name;
    transl[field_count++].item= item;
  }
  field_translation= transl;
  field_translation_end= transl + field_count;

exit:
  if (arena)
    thd->restore_active_arena(arena, &backup);

  return res;
}


/**
  @brief
  Create field translation for mergeable derived table/view.

  @param thd  Thread handle

  @details
  Create field translation for mergeable derived table/view.

  @return FALSE ok.
  @return TRUE an error occur.
*/

bool TABLE_LIST::setup_underlying(THD *thd)
{
  DBUG_ENTER("TABLE_LIST::setup_underlying");

  if (!view || (!field_translation && merge_underlying_list))
  {
    SELECT_LEX *select= get_single_select();
    
    if (create_field_translation(thd))
      DBUG_RETURN(TRUE);

    /* full text function moving to current select */
    if (select->ftfunc_list->elements)
    {
      Item_func_match *ifm;
      SELECT_LEX *current_select= thd->lex->current_select;
      List_iterator_fast<Item_func_match>
        li(*(select_lex->ftfunc_list));
      while ((ifm= li++))
        current_select->ftfunc_list->push_front(ifm);
    }
  }
  DBUG_RETURN(FALSE);
}


/*
   Prepare where expression of derived table/view

  SYNOPSIS
    TABLE_LIST::prep_where()
    thd             - thread handler
    conds           - condition of this JOIN
    no_where_clause - do not build WHERE or ON outer qwery do not need it
                      (it is INSERT), we do not need conds if this flag is set

  NOTE: have to be called befor CHECK OPTION preparation, because it makes
  fix_fields for view WHERE clause

  RETURN
    FALSE - OK
    TRUE  - error
*/

bool TABLE_LIST::prep_where(THD *thd, Item **conds,
                               bool no_where_clause)
{
  DBUG_ENTER("TABLE_LIST::prep_where");

  for (TABLE_LIST *tbl= merge_underlying_list; tbl; tbl= tbl->next_local)
  {
    if (tbl->is_view_or_derived() &&
        tbl->prep_where(thd, conds, no_where_clause))
    {
      DBUG_RETURN(TRUE);
    }
  }

  if (where)
  {
    if (where->fixed)
      where->update_used_tables();
    if (!where->fixed && where->fix_fields(thd, &where))
    {
      DBUG_RETURN(TRUE);
    }

    /*
      check that it is not VIEW in which we insert with INSERT SELECT
      (in this case we can't add view WHERE condition to main SELECT_LEX)
    */
    if (!no_where_clause && !where_processed)
    {
      TABLE_LIST *tbl= this;
      Query_arena *arena= thd->stmt_arena, backup;
      arena= thd->activate_stmt_arena_if_needed(&backup);  // For easier test

      /* Go up to join tree and try to find left join */
      for (; tbl; tbl= tbl->embedding)
      {
        if (tbl->outer_join)
        {
          /*
            Store WHERE condition to ON expression for outer join, because
            we can't use WHERE to correctly execute left joins on VIEWs and
            this expression will not be moved to WHERE condition (i.e. will
            be clean correctly for PS/SP)
          */
          tbl->on_expr= and_conds(tbl->on_expr,
                                  where->copy_andor_structure(thd));
          break;
        }
      }
      if (tbl == 0)
      {
        if (*conds && !(*conds)->fixed)
	  (*conds)->fix_fields(thd, conds);
        *conds= and_conds(*conds, where->copy_andor_structure(thd));
        if (*conds && !(*conds)->fixed)
          (*conds)->fix_fields(thd, conds);        
      }
      if (arena)
        thd->restore_active_arena(arena, &backup);
      where_processed= TRUE;
    }
  }

  DBUG_RETURN(FALSE);
}

/**
  Check that table/view is updatable and if it has single
  underlying tables/views it is also updatable

  @return Result of the check.
*/

bool TABLE_LIST::single_table_updatable()
{
  if (!updatable)
    return false;
  if (view_tables && view_tables->elements == 1)
  {
    /*
      We need to check deeply only single table views. Multi-table views
      will be turned to multi-table updates and then checked by leaf tables
    */
    return view_tables->head()->single_table_updatable();
  }
  return true;
}


/*
  Merge ON expressions for a view

  SYNOPSIS
    merge_on_conds()
    thd             thread handle
    table           table for the VIEW
    is_cascaded     TRUE <=> merge ON expressions from underlying views

  DESCRIPTION
    This function returns the result of ANDing the ON expressions
    of the given view and all underlying views. The ON expressions
    of the underlying views are added only if is_cascaded is TRUE.

  RETURN
    Pointer to the built expression if there is any.
    Otherwise and in the case of a failure NULL is returned.
*/

static Item *
merge_on_conds(THD *thd, TABLE_LIST *table, bool is_cascaded)
{
  DBUG_ENTER("merge_on_conds");

  Item *cond= NULL;
  DBUG_PRINT("info", ("alias: %s", table->alias));
  if (table->on_expr)
    cond= table->on_expr->copy_andor_structure(thd);
  if (!table->view)
    DBUG_RETURN(cond);
  for (TABLE_LIST *tbl= (TABLE_LIST*)table->view->select_lex.table_list.first;
       tbl;
       tbl= tbl->next_local)
  {
    if (tbl->view && !is_cascaded)
      continue;
    cond= and_conds(cond, merge_on_conds(thd, tbl, is_cascaded));
  }
  DBUG_RETURN(cond);
}


/*
  Prepare check option expression of table

  SYNOPSIS
    TABLE_LIST::prep_check_option()
    thd             - thread handler
    check_opt_type  - WITH CHECK OPTION type (VIEW_CHECK_NONE,
                      VIEW_CHECK_LOCAL, VIEW_CHECK_CASCADED)
                      we use this parameter instead of direct check of
                      effective_with_check to change type of underlying
                      views to VIEW_CHECK_CASCADED if outer view have
                      such option and prevent processing of underlying
                      view check options if outer view have just
                      VIEW_CHECK_LOCAL option.

  NOTE
    This method builds check option condition to use it later on
    every call (usual execution or every SP/PS call).
    This method have to be called after WHERE preparation
    (TABLE_LIST::prep_where)

  RETURN
    FALSE - OK
    TRUE  - error
*/

bool TABLE_LIST::prep_check_option(THD *thd, uint8 check_opt_type)
{
  DBUG_ENTER("TABLE_LIST::prep_check_option");
  bool is_cascaded= check_opt_type == VIEW_CHECK_CASCADED;
  TABLE_LIST *merge_underlying_list= view->select_lex.get_table_list();
  for (TABLE_LIST *tbl= merge_underlying_list; tbl; tbl= tbl->next_local)
  {
    /* see comment of check_opt_type parameter */
    if (tbl->view && tbl->prep_check_option(thd, (is_cascaded ?
                                                  VIEW_CHECK_CASCADED :
                                                  VIEW_CHECK_NONE)))
      DBUG_RETURN(TRUE);
  }

  if (check_opt_type && !check_option_processed)
  {
    Query_arena *arena= thd->stmt_arena, backup;
    arena= thd->activate_stmt_arena_if_needed(&backup);  // For easier test

    if (where)
    {
      check_option= where->copy_andor_structure(thd);
    }
    if (is_cascaded)
    {
      for (TABLE_LIST *tbl= merge_underlying_list; tbl; tbl= tbl->next_local)
      {
        if (tbl->check_option)
          check_option= and_conds(check_option, tbl->check_option);
      }
    }
    check_option= and_conds(check_option,
                            merge_on_conds(thd, this, is_cascaded));

    if (arena)
      thd->restore_active_arena(arena, &backup);
    check_option_processed= TRUE;

  }

  if (check_option)
  {
    const char *save_where= thd->where;
    thd->where= "check option";
    if ((!check_option->fixed &&
         check_option->fix_fields(thd, &check_option)) ||
        check_option->check_cols(1))
    {
      DBUG_RETURN(TRUE);
    }
    thd->where= save_where;
  }
  DBUG_RETURN(FALSE);
}


/**
  Hide errors which show view underlying table information. 
  There are currently two mechanisms at work that handle errors for views,
  this one and a more general mechanism based on an Internal_error_handler,
  see Show_create_error_handler. The latter handles errors encountered during
  execution of SHOW CREATE VIEW, while the mechanism using this method is
  handles SELECT from views. The two methods should not clash.

  @param[in,out]  thd     thread handler

  @pre This method can be called only if there is an error.
*/

void TABLE_LIST::hide_view_error(THD *thd)
{
  if (thd->killed || thd->get_internal_handler())
    return;
  /* Hide "Unknown column" or "Unknown function" error */
  DBUG_ASSERT(thd->is_error());

  if (thd->stmt_da->sql_errno() == ER_BAD_FIELD_ERROR ||
      thd->stmt_da->sql_errno() == ER_SP_DOES_NOT_EXIST ||
      thd->stmt_da->sql_errno() == ER_FUNC_INEXISTENT_NAME_COLLISION ||
      thd->stmt_da->sql_errno() == ER_PROCACCESS_DENIED_ERROR ||
      thd->stmt_da->sql_errno() == ER_COLUMNACCESS_DENIED_ERROR ||
      thd->stmt_da->sql_errno() == ER_TABLEACCESS_DENIED_ERROR ||
      thd->stmt_da->sql_errno() == ER_TABLE_NOT_LOCKED ||
      thd->stmt_da->sql_errno() == ER_NO_SUCH_TABLE)
  {
    TABLE_LIST *top= top_table();
    thd->clear_error();
    my_error(ER_VIEW_INVALID, MYF(0), top->view_db.str, top->view_name.str);
  }
  else if (thd->stmt_da->sql_errno() == ER_NO_DEFAULT_FOR_FIELD)
  {
    TABLE_LIST *top= top_table();
    thd->clear_error();
    // TODO: make correct error message
    my_error(ER_NO_DEFAULT_FOR_VIEW_FIELD, MYF(0),
             top->view_db.str, top->view_name.str);
  }
}


/*
  Find underlying base tables (TABLE_LIST) which represent given
  table_to_find (TABLE)

  SYNOPSIS
    TABLE_LIST::find_underlying_table()
    table_to_find table to find

  RETURN
    0  table is not found
    found table reference
*/

TABLE_LIST *TABLE_LIST::find_underlying_table(TABLE *table_to_find)
{
  /* is this real table and table which we are looking for? */
  if (table == table_to_find && view == 0)
    return this;
  if (!view)
    return 0;

  for (TABLE_LIST *tbl= view->select_lex.get_table_list();
       tbl;
       tbl= tbl->next_local)
  {
    TABLE_LIST *result;
    if ((result= tbl->find_underlying_table(table_to_find)))
      return result;
  }
  return 0;
}

/*
  cleanup items belonged to view fields translation table

  SYNOPSIS
    TABLE_LIST::cleanup_items()
*/

void TABLE_LIST::cleanup_items()
{
  if (!field_translation)
    return;

  for (Field_translator *transl= field_translation;
       transl < field_translation_end;
       transl++)
    transl->item->walk(&Item::cleanup_processor, 0, 0);
}


/*
  check CHECK OPTION condition

  SYNOPSIS
    TABLE_LIST::view_check_option()
    ignore_failure ignore check option fail

  RETURN
    VIEW_CHECK_OK     OK
    VIEW_CHECK_ERROR  FAILED
    VIEW_CHECK_SKIP   FAILED, but continue
*/

int TABLE_LIST::view_check_option(THD *thd, bool ignore_failure)
{
  if (check_option && check_option->val_int() == 0)
  {
    TABLE_LIST *main_view= top_table();
    if (ignore_failure)
    {
      push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                          ER_VIEW_CHECK_FAILED, ER(ER_VIEW_CHECK_FAILED),
                          main_view->view_db.str, main_view->view_name.str);
      return(VIEW_CHECK_SKIP);
    }
    my_error(ER_VIEW_CHECK_FAILED, MYF(0), main_view->view_db.str,
             main_view->view_name.str);
    return(VIEW_CHECK_ERROR);
  }
  return(VIEW_CHECK_OK);
}


/*
  Find table in underlying tables by mask and check that only this
  table belong to given mask

  SYNOPSIS
    TABLE_LIST::check_single_table()
    table_arg	reference on variable where to store found table
		(should be 0 on call, to find table, or point to table for
		unique test)
    map         bit mask of tables
    view_arg    view for which we are looking table

  RETURN
    FALSE table not found or found only one
    TRUE  found several tables
*/

bool TABLE_LIST::check_single_table(TABLE_LIST **table_arg,
                                       table_map map,
                                       TABLE_LIST *view_arg)
{
  if (!select_lex)
    return FALSE;
  DBUG_ASSERT(is_merged_derived());
  for (TABLE_LIST *tbl= get_single_select()->get_table_list();
       tbl;
       tbl= tbl->next_local)
  {
    /*
      Merged view has also temporary table attached (in 5.2 if it has table
      then it was real table), so we have filter such temporary tables out
      by checking that it is not merged view
    */
    if (tbl->table &&
        !(tbl->is_view() &&
          tbl->is_merged_derived()))
    {
      if (tbl->table->map & map)
      {
	if (*table_arg)
	  return TRUE;
        *table_arg= tbl;
        tbl->check_option= view_arg->check_option;
      }
    }
    else if (tbl->check_single_table(table_arg, map, view_arg))
      return TRUE;
  }
  return FALSE;
}


/*
  Set insert_values buffer

  SYNOPSIS
    set_insert_values()
    mem_root   memory pool for allocating

  RETURN
    FALSE - OK
    TRUE  - out of memory
*/

bool TABLE_LIST::set_insert_values(MEM_ROOT *mem_root)
{
  if (table)
  {
    if (!table->insert_values &&
        !(table->insert_values= (uchar *)alloc_root(mem_root,
                                                   table->s->rec_buff_length)))
      return TRUE;
  }
  else
  {
    DBUG_ASSERT(is_view_or_derived() && is_merged_derived());
    for (TABLE_LIST *tbl= (TABLE_LIST*)view->select_lex.table_list.first;
         tbl;
         tbl= tbl->next_local)
      if (tbl->set_insert_values(mem_root))
        return TRUE;
  }
  return FALSE;
}


/*
  Test if this is a leaf with respect to name resolution.

  SYNOPSIS
    TABLE_LIST::is_leaf_for_name_resolution()

  DESCRIPTION
    A table reference is a leaf with respect to name resolution if
    it is either a leaf node in a nested join tree (table, view,
    schema table, subquery), or an inner node that represents a
    NATURAL/USING join, or a nested join with materialized join
    columns.

  RETURN
    TRUE if a leaf, FALSE otherwise.
*/
bool TABLE_LIST::is_leaf_for_name_resolution()
{
  return (is_merged_derived() || is_natural_join || is_join_columns_complete ||
          !nested_join);
}


/*
  Retrieve the first (left-most) leaf in a nested join tree with
  respect to name resolution.

  SYNOPSIS
    TABLE_LIST::first_leaf_for_name_resolution()

  DESCRIPTION
    Given that 'this' is a nested table reference, recursively walk
    down the left-most children of 'this' until we reach a leaf
    table reference with respect to name resolution.

  IMPLEMENTATION
    The left-most child of a nested table reference is the last element
    in the list of children because the children are inserted in
    reverse order.

  RETURN
    If 'this' is a nested table reference - the left-most child of
      the tree rooted in 'this',
    else return 'this'
*/

TABLE_LIST *TABLE_LIST::first_leaf_for_name_resolution()
{
  TABLE_LIST *cur_table_ref;
  NESTED_JOIN *cur_nested_join;
  LINT_INIT(cur_table_ref);

  if (is_leaf_for_name_resolution())
    return this;
  DBUG_ASSERT(nested_join);

  for (cur_nested_join= nested_join;
       cur_nested_join;
       cur_nested_join= cur_table_ref->nested_join)
  {
    List_iterator_fast<TABLE_LIST> it(cur_nested_join->join_list);
    cur_table_ref= it++;
    /*
      If the current nested join is a RIGHT JOIN, the operands in
      'join_list' are in reverse order, thus the first operand is
      already at the front of the list. Otherwise the first operand
      is in the end of the list of join operands.
    */
    if (!(cur_table_ref->outer_join & JOIN_TYPE_RIGHT))
    {
      TABLE_LIST *next;
      while ((next= it++))
        cur_table_ref= next;
    }
    if (cur_table_ref->is_leaf_for_name_resolution())
      break;
  }
  return cur_table_ref;
}


/*
  Retrieve the last (right-most) leaf in a nested join tree with
  respect to name resolution.

  SYNOPSIS
    TABLE_LIST::last_leaf_for_name_resolution()

  DESCRIPTION
    Given that 'this' is a nested table reference, recursively walk
    down the right-most children of 'this' until we reach a leaf
    table reference with respect to name resolution.

  IMPLEMENTATION
    The right-most child of a nested table reference is the first
    element in the list of children because the children are inserted
    in reverse order.

  RETURN
    - If 'this' is a nested table reference - the right-most child of
      the tree rooted in 'this',
    - else - 'this'
*/

TABLE_LIST *TABLE_LIST::last_leaf_for_name_resolution()
{
  TABLE_LIST *cur_table_ref= this;
  NESTED_JOIN *cur_nested_join;

  if (is_leaf_for_name_resolution())
    return this;
  DBUG_ASSERT(nested_join);

  for (cur_nested_join= nested_join;
       cur_nested_join;
       cur_nested_join= cur_table_ref->nested_join)
  {
    cur_table_ref= cur_nested_join->join_list.head();
    /*
      If the current nested is a RIGHT JOIN, the operands in
      'join_list' are in reverse order, thus the last operand is in the
      end of the list.
    */
    if ((cur_table_ref->outer_join & JOIN_TYPE_RIGHT))
    {
      List_iterator_fast<TABLE_LIST> it(cur_nested_join->join_list);
      TABLE_LIST *next;
      cur_table_ref= it++;
      while ((next= it++))
        cur_table_ref= next;
    }
    if (cur_table_ref->is_leaf_for_name_resolution())
      break;
  }
  return cur_table_ref;
}


/*
  Register access mode which we need for underlying tables

  SYNOPSIS
    register_want_access()
    want_access          Acess which we require
*/

void TABLE_LIST::register_want_access(ulong want_access)
{
  /* Remove SHOW_VIEW_ACL, because it will be checked during making view */
  want_access&= ~SHOW_VIEW_ACL;
  if (belong_to_view)
  {
    grant.want_privilege= want_access;
    if (table)
      table->grant.want_privilege= want_access;
  }
  if (!view)
    return;
  for (TABLE_LIST *tbl= view->select_lex.get_table_list();
       tbl;
       tbl= tbl->next_local)
    tbl->register_want_access(want_access);
}


/*
  Load security context information for this view

  SYNOPSIS
    TABLE_LIST::prepare_view_security_context()
    thd                  [in] thread handler

  RETURN
    FALSE  OK
    TRUE   Error
*/

#ifndef NO_EMBEDDED_ACCESS_CHECKS
bool TABLE_LIST::prepare_view_security_context(THD *thd)
{
  DBUG_ENTER("TABLE_LIST::prepare_view_security_context");
  DBUG_PRINT("enter", ("table: %s", alias));

  DBUG_ASSERT(!prelocking_placeholder && view);
  if (view_suid)
  {
    DBUG_PRINT("info", ("This table is suid view => load contest"));
    DBUG_ASSERT(view && view_sctx);
    if (acl_getroot(view_sctx, definer.user.str, definer.host.str,
                                definer.host.str, thd->db))
    {
      if ((thd->lex->sql_command == SQLCOM_SHOW_CREATE) ||
          (thd->lex->sql_command == SQLCOM_SHOW_FIELDS))
      {
        push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_NOTE, 
                            ER_NO_SUCH_USER, 
                            ER(ER_NO_SUCH_USER),
                            definer.user.str, definer.host.str);
      }
      else
      {
        if (thd->security_ctx->master_access & SUPER_ACL)
        {
          my_error(ER_NO_SUCH_USER, MYF(0), definer.user.str, definer.host.str);

        }
        else
        {
          if (thd->password == 2)
            my_error(ER_ACCESS_DENIED_NO_PASSWORD_ERROR, MYF(0),
                     thd->security_ctx->priv_user,
                     thd->security_ctx->priv_host);
          else
            my_error(ER_ACCESS_DENIED_ERROR, MYF(0),
                     thd->security_ctx->priv_user,
                     thd->security_ctx->priv_host,
                     (thd->password ?  ER(ER_YES) : ER(ER_NO)));
        }
        DBUG_RETURN(TRUE);
      }
    }
  }
  DBUG_RETURN(FALSE);
}
#endif


/*
  Find security context of current view

  SYNOPSIS
    TABLE_LIST::find_view_security_context()
    thd                  [in] thread handler

*/

#ifndef NO_EMBEDDED_ACCESS_CHECKS
Security_context *TABLE_LIST::find_view_security_context(THD *thd)
{
  Security_context *sctx;
  TABLE_LIST *upper_view= this;
  DBUG_ENTER("TABLE_LIST::find_view_security_context");

  DBUG_ASSERT(view);
  while (upper_view && !upper_view->view_suid)
  {
    DBUG_ASSERT(!upper_view->prelocking_placeholder);
    upper_view= upper_view->referencing_view;
  }
  if (upper_view)
  {
    DBUG_PRINT("info", ("Securety context of view %s will be used",
                        upper_view->alias));
    sctx= upper_view->view_sctx;
    DBUG_ASSERT(sctx);
  }
  else
  {
    DBUG_PRINT("info", ("Current global context will be used"));
    sctx= thd->security_ctx;
  }
  DBUG_RETURN(sctx);
}
#endif


/*
  Prepare security context and load underlying tables priveleges for view

  SYNOPSIS
    TABLE_LIST::prepare_security()
    thd                  [in] thread handler

  RETURN
    FALSE  OK
    TRUE   Error
*/

bool TABLE_LIST::prepare_security(THD *thd)
{
  List_iterator_fast<TABLE_LIST> tb(*view_tables);
  TABLE_LIST *tbl;
  DBUG_ENTER("TABLE_LIST::prepare_security");
#ifndef NO_EMBEDDED_ACCESS_CHECKS
  Security_context *save_security_ctx= thd->security_ctx;

  DBUG_ASSERT(!prelocking_placeholder);
  if (prepare_view_security_context(thd))
    DBUG_RETURN(TRUE);
  thd->security_ctx= find_view_security_context(thd);
  while ((tbl= tb++))
  {
    DBUG_ASSERT(tbl->referencing_view);
    char *local_db, *local_table_name;
    if (tbl->view)
    {
      local_db= tbl->view_db.str;
      local_table_name= tbl->view_name.str;
    }
    else
    {
      local_db= tbl->db;
      local_table_name= tbl->table_name;
    }
    fill_effective_table_privileges(thd, &tbl->grant, local_db,
                                    local_table_name);
    if (tbl->table)
      tbl->table->grant= grant;
  }
  thd->security_ctx= save_security_ctx;
#else
  while ((tbl= tb++))
    tbl->grant.privilege= ~NO_ACCESS;
#endif
  DBUG_RETURN(FALSE);
}

#ifndef DBUG_OFF
void TABLE_LIST::set_check_merged()
{
  DBUG_ASSERT(derived);
  /*
    It is not simple to check all, but at least this should be checked:
    this select is not excluded or the exclusion came from above.
  */
  DBUG_ASSERT(!derived->first_select()->exclude_from_table_unique_test ||
              derived->outer_select()->
              exclude_from_table_unique_test);
}
#endif

void TABLE_LIST::set_check_materialized()
{
  DBUG_ASSERT(derived);
  if (!derived->first_select()->exclude_from_table_unique_test)
    derived->set_unique_exclude();
  else
  {
    /*
      The subtree should be already excluded
    */
    DBUG_ASSERT(!derived->first_select()->first_inner_unit() ||
                derived->first_select()->first_inner_unit()->first_select()->
                exclude_from_table_unique_test);
  }
}

TABLE *TABLE_LIST::get_real_join_table()
{
  TABLE_LIST *tbl= this;
  while (tbl->table == NULL || tbl->table->reginfo.join_tab == NULL)
  {
    if (tbl->view == NULL && tbl->derived == NULL)
      break;
    /* we do not support merging of union yet */
    DBUG_ASSERT(tbl->view == NULL ||
               tbl->view->select_lex.next_select() == NULL);
    DBUG_ASSERT(tbl->derived == NULL ||
               tbl->derived->first_select()->next_select() == NULL);

    {
      List_iterator_fast<TABLE_LIST> ti;
      {
        List_iterator_fast<TABLE_LIST>
          ti(tbl->view != NULL ?
             tbl->view->select_lex.top_join_list :
             tbl->derived->first_select()->top_join_list);
        for (;;)
        {
          tbl= NULL;
          /*
            Find left table in outer join on this level
            (the list is reverted).
          */
          for (TABLE_LIST *t= ti++; t; t= ti++)
            tbl= t;
          /*
            It is impossible that the list is empty
            so tbl can't be NULL after above loop.
          */
          if (!tbl->nested_join)
            break;
          /* go deeper if we've found nested join */
          ti= tbl->nested_join->join_list;
        }
      }
    }
  }

  return tbl->table;
}


Natural_join_column::Natural_join_column(Field_translator *field_param,
                                         TABLE_LIST *tab)
{
  DBUG_ASSERT(tab->field_translation);
  view_field= field_param;
  table_field= NULL;
  table_ref= tab;
  is_common= FALSE;
}


Natural_join_column::Natural_join_column(Item_field *field_param,
                                         TABLE_LIST *tab)
{
  DBUG_ASSERT(tab->table == field_param->field->table);
  table_field= field_param;
  view_field= NULL;
  table_ref= tab;
  is_common= FALSE;
}


const char *Natural_join_column::name()
{
  if (view_field)
  {
    DBUG_ASSERT(table_field == NULL);
    return view_field->name;
  }

  return table_field->field_name;
}


Item *Natural_join_column::create_item(THD *thd)
{
  if (view_field)
  {
    DBUG_ASSERT(table_field == NULL);
    return create_view_field(thd, table_ref, &view_field->item,
                             view_field->name);
  }
  return table_field;
}


Field *Natural_join_column::field()
{
  if (view_field)
  {
    DBUG_ASSERT(table_field == NULL);
    return NULL;
  }
  return table_field->field;
}


const char *Natural_join_column::table_name()
{
  DBUG_ASSERT(table_ref);
  return table_ref->alias;
}


const char *Natural_join_column::db_name()
{
  if (view_field)
    return table_ref->view_db.str;

  /*
    Test that TABLE_LIST::db is the same as TABLE_SHARE::db to
    ensure consistency. An exception are I_S schema tables, which
    are inconsistent in this respect.
  */
  DBUG_ASSERT(!strcmp(table_ref->db,
                      table_ref->table->s->db.str) ||
              (table_ref->schema_table &&
               is_infoschema_db(table_ref->table->s->db.str,
                                table_ref->table->s->db.length)) ||
               table_ref->is_materialized_derived());
  return table_ref->db;
}


GRANT_INFO *Natural_join_column::grant()
{
/*  if (view_field)
    return &(table_ref->grant);
  return &(table_ref->table->grant);*/
  /*
    Have to check algorithm because merged derived also has
    field_translation.
  */
//if (table_ref->effective_algorithm == DTYPE_ALGORITHM_MERGE)
  if (table_ref->is_merged_derived())
    return &(table_ref->grant);
  return &(table_ref->table->grant);
}


void Field_iterator_view::set(TABLE_LIST *table)
{
  DBUG_ASSERT(table->field_translation);
  view= table;
  ptr= table->field_translation;
  array_end= table->field_translation_end;
}


const char *Field_iterator_table::name()
{
  return (*ptr)->field_name;
}


Item *Field_iterator_table::create_item(THD *thd)
{
  SELECT_LEX *select= thd->lex->current_select;

  Item_field *item= new Item_field(thd, &select->context, *ptr);
  if (item && thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY &&
      !thd->lex->in_sum_func && select->cur_pos_in_select_list != UNDEF_POS)
  {
    select->non_agg_fields.push_back(item);
    item->marker= select->cur_pos_in_select_list;
    select->set_non_agg_field_used(true);
  }
  return item;
}


const char *Field_iterator_view::name()
{
  return ptr->name;
}


Item *Field_iterator_view::create_item(THD *thd)
{
  return create_view_field(thd, view, &ptr->item, ptr->name);
}

Item *create_view_field(THD *thd, TABLE_LIST *view, Item **field_ref,
                        const char *name)
{
  bool save_wrapper= thd->lex->select_lex.no_wrap_view_item;
  Item *field= *field_ref;
  DBUG_ENTER("create_view_field");

  if (view->schema_table_reformed)
  {
    /*
      Translation table items are always Item_fields and already fixed
      ('mysql_schema_table' function). So we can return directly the
      field. This case happens only for 'show & where' commands.
    */
    DBUG_ASSERT(field && field->fixed);
    DBUG_RETURN(field);
  }

  DBUG_ASSERT(field);
  thd->lex->current_select->no_wrap_view_item= TRUE;
  if (!field->fixed)
  {
    if (field->fix_fields(thd, field_ref))
    {
      thd->lex->current_select->no_wrap_view_item= save_wrapper;
      DBUG_RETURN(0);
    }
    field= *field_ref;
  }
  thd->lex->current_select->no_wrap_view_item= save_wrapper;
  if (save_wrapper)
  {
    DBUG_RETURN(field);
  }
  Item *item= new Item_direct_view_ref(&view->view->select_lex.context,
                                       field_ref, view->alias,
                                       name, view);
  /*
    Force creation of nullable item for the result tmp table for outer joined
    views/derived tables.
  */
  if (view->table && view->table->maybe_null)
    item->maybe_null= TRUE;
  /* Save item in case we will need to fall back to materialization. */
  view->used_items.push_front(item);
  DBUG_RETURN(item);
}


void Field_iterator_natural_join::set(TABLE_LIST *table_ref)
{
  DBUG_ASSERT(table_ref->join_columns);
  column_ref_it.init(*(table_ref->join_columns));
  cur_column_ref= column_ref_it++;
}


void Field_iterator_natural_join::next()
{
  cur_column_ref= column_ref_it++;
  DBUG_ASSERT(!cur_column_ref || ! cur_column_ref->table_field ||
              cur_column_ref->table_ref->table ==
              cur_column_ref->table_field->field->table);
}


void Field_iterator_table_ref::set_field_iterator()
{
  DBUG_ENTER("Field_iterator_table_ref::set_field_iterator");
  /*
    If the table reference we are iterating over is a natural join, or it is
    an operand of a natural join, and TABLE_LIST::join_columns contains all
    the columns of the join operand, then we pick the columns from
    TABLE_LIST::join_columns, instead of the  orginial container of the
    columns of the join operator.
  */
  if (table_ref->is_join_columns_complete)
  {
    /* Necesary, but insufficient conditions. */
    DBUG_ASSERT(table_ref->is_natural_join ||
                table_ref->nested_join ||
                (table_ref->join_columns &&
                 /* This is a merge view. */
                 ((table_ref->field_translation &&
                   table_ref->join_columns->elements ==
                   (ulong)(table_ref->field_translation_end -
                           table_ref->field_translation)) ||
                  /* This is stored table or a tmptable view. */
                  (!table_ref->field_translation &&
                   table_ref->join_columns->elements ==
                   table_ref->table->s->fields))));
    field_it= &natural_join_it;
    DBUG_PRINT("info",("field_it for '%s' is Field_iterator_natural_join",
                       table_ref->alias));
  }
  /* This is a merge view, so use field_translation. */
  else if (table_ref->field_translation)
  {
    DBUG_ASSERT(table_ref->is_merged_derived());
    field_it= &view_field_it;
    DBUG_PRINT("info", ("field_it for '%s' is Field_iterator_view",
                        table_ref->alias));
  }
  /* This is a base table or stored view. */
  else
  {
    DBUG_ASSERT(table_ref->table || table_ref->view);
    field_it= &table_field_it;
    DBUG_PRINT("info", ("field_it for '%s' is Field_iterator_table",
                        table_ref->alias));
  }
  field_it->set(table_ref);
  DBUG_VOID_RETURN;
}


void Field_iterator_table_ref::set(TABLE_LIST *table)
{
  DBUG_ASSERT(table);
  first_leaf= table->first_leaf_for_name_resolution();
  last_leaf=  table->last_leaf_for_name_resolution();
  DBUG_ASSERT(first_leaf && last_leaf);
  table_ref= first_leaf;
  set_field_iterator();
}


void Field_iterator_table_ref::next()
{
  /* Move to the next field in the current table reference. */
  field_it->next();
  /*
    If all fields of the current table reference are exhausted, move to
    the next leaf table reference.
  */
  if (field_it->end_of_fields() && table_ref != last_leaf)
  {
    table_ref= table_ref->next_name_resolution_table;
    DBUG_ASSERT(table_ref);
    set_field_iterator();
  }
}


const char *Field_iterator_table_ref::get_table_name()
{
  if (table_ref->view)
    return table_ref->view_name.str;
  else if (table_ref->is_natural_join)
    return natural_join_it.column_ref()->table_name();

  DBUG_ASSERT(!strcmp(table_ref->table_name,
                      table_ref->table->s->table_name.str));
  return table_ref->table_name;
}


const char *Field_iterator_table_ref::get_db_name()
{
  if (table_ref->view)
    return table_ref->view_db.str;
  else if (table_ref->is_natural_join)
    return natural_join_it.column_ref()->db_name();

  /*
    Test that TABLE_LIST::db is the same as TABLE_SHARE::db to
    ensure consistency. An exception are I_S schema tables, which
    are inconsistent in this respect.
  */
  DBUG_ASSERT(!strcmp(table_ref->db, table_ref->table->s->db.str) ||
              (table_ref->schema_table &&
               is_infoschema_db(table_ref->table->s->db.str,
                                table_ref->table->s->db.length)));

  return table_ref->db;
}


GRANT_INFO *Field_iterator_table_ref::grant()
{
  if (table_ref->view)
    return &(table_ref->grant);
  else if (table_ref->is_natural_join)
    return natural_join_it.column_ref()->grant();
  return &(table_ref->table->grant);
}


/*
  Create new or return existing column reference to a column of a
  natural/using join.

  SYNOPSIS
    Field_iterator_table_ref::get_or_create_column_ref()
    parent_table_ref  the parent table reference over which the
                      iterator is iterating

  DESCRIPTION
    Create a new natural join column for the current field of the
    iterator if no such column was created, or return an already
    created natural join column. The former happens for base tables or
    views, and the latter for natural/using joins. If a new field is
    created, then the field is added to 'parent_table_ref' if it is
    given, or to the original table referene of the field if
    parent_table_ref == NULL.

  NOTES
    This method is designed so that when a Field_iterator_table_ref
    walks through the fields of a table reference, all its fields
    are created and stored as follows:
    - If the table reference being iterated is a stored table, view or
      natural/using join, store all natural join columns in a list
      attached to that table reference.
    - If the table reference being iterated is a nested join that is
      not natural/using join, then do not materialize its result
      fields. This is OK because for such table references
      Field_iterator_table_ref iterates over the fields of the nested
      table references (recursively). In this way we avoid the storage
      of unnecessay copies of result columns of nested joins.

  RETURN
    #     Pointer to a column of a natural join (or its operand)
    NULL  No memory to allocate the column
*/

Natural_join_column *
Field_iterator_table_ref::get_or_create_column_ref(THD *thd, TABLE_LIST *parent_table_ref)
{
  Natural_join_column *nj_col;
  bool is_created= TRUE;
  uint field_count;
  TABLE_LIST *add_table_ref= parent_table_ref ?
                             parent_table_ref : table_ref;
  LINT_INIT(field_count);

  if (field_it == &table_field_it)
  {
    /* The field belongs to a stored table. */
    Field *tmp_field= table_field_it.field();
    Item_field *tmp_item=
      new Item_field(thd, &thd->lex->current_select->context, tmp_field);
    if (!tmp_item)
      return NULL;
    nj_col= new Natural_join_column(tmp_item, table_ref);
    field_count= table_ref->table->s->fields;
  }
  else if (field_it == &view_field_it)
  {
    /* The field belongs to a merge view or information schema table. */
    Field_translator *translated_field= view_field_it.field_translator();
    nj_col= new Natural_join_column(translated_field, table_ref);
    field_count= table_ref->field_translation_end -
                 table_ref->field_translation;
  }
  else
  {
    /*
      The field belongs to a NATURAL join, therefore the column reference was
      already created via one of the two constructor calls above. In this case
      we just return the already created column reference.
    */
    DBUG_ASSERT(table_ref->is_join_columns_complete);
    is_created= FALSE;
    nj_col= natural_join_it.column_ref();
    DBUG_ASSERT(nj_col);
  }
  DBUG_ASSERT(!nj_col->table_field ||
              nj_col->table_ref->table == nj_col->table_field->field->table);

  /*
    If the natural join column was just created add it to the list of
    natural join columns of either 'parent_table_ref' or to the table
    reference that directly contains the original field.
  */
  if (is_created)
  {
    /* Make sure not all columns were materialized. */
    DBUG_ASSERT(!add_table_ref->is_join_columns_complete);
    if (!add_table_ref->join_columns)
    {
      /* Create a list of natural join columns on demand. */
      if (!(add_table_ref->join_columns= new List<Natural_join_column>))
        return NULL;
      add_table_ref->is_join_columns_complete= FALSE;
    }
    add_table_ref->join_columns->push_back(nj_col);
    /*
      If new fields are added to their original table reference, mark if
      all fields were added. We do it here as the caller has no easy way
      of knowing when to do it.
      If the fields are being added to parent_table_ref, then the caller
      must take care to mark when all fields are created/added.
    */
    if (!parent_table_ref &&
        add_table_ref->join_columns->elements == field_count)
      add_table_ref->is_join_columns_complete= TRUE;
  }

  return nj_col;
}


/*
  Return an existing reference to a column of a natural/using join.

  SYNOPSIS
    Field_iterator_table_ref::get_natural_column_ref()

  DESCRIPTION
    The method should be called in contexts where it is expected that
    all natural join columns are already created, and that the column
    being retrieved is a Natural_join_column.

  RETURN
    #     Pointer to a column of a natural join (or its operand)
    NULL  No memory to allocate the column
*/

Natural_join_column *
Field_iterator_table_ref::get_natural_column_ref()
{
  Natural_join_column *nj_col;

  DBUG_ASSERT(field_it == &natural_join_it);
  /*
    The field belongs to a NATURAL join, therefore the column reference was
    already created via one of the two constructor calls above. In this case
    we just return the already created column reference.
  */
  nj_col= natural_join_it.column_ref();
  DBUG_ASSERT(nj_col &&
              (!nj_col->table_field ||
               nj_col->table_ref->table == nj_col->table_field->field->table));
  return nj_col;
}

/*****************************************************************************
  Functions to handle column usage bitmaps (read_set, write_set etc...)
*****************************************************************************/

/* Reset all columns bitmaps */

void TABLE::clear_column_bitmaps()
{
  /*
    Reset column read/write usage. It's identical to:
    bitmap_clear_all(&table->def_read_set);
    bitmap_clear_all(&table->def_write_set);
    bitmap_clear_all(&table->def_vcol_set);
  */
  bzero((char*) def_read_set.bitmap, s->column_bitmap_size*3);
  column_bitmaps_set(&def_read_set, &def_write_set, &def_vcol_set);
}


/*
  Tell handler we are going to call position() and rnd_pos() later.
  
  NOTES:
  This is needed for handlers that uses the primary key to find the
  row. In this case we have to extend the read bitmap with the primary
  key fields.
*/

void TABLE::prepare_for_position()
{
  DBUG_ENTER("TABLE::prepare_for_position");

  if ((file->ha_table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX) &&
      s->primary_key < MAX_KEY)
  {
    mark_columns_used_by_index_no_reset(s->primary_key, read_set);
    /* signal change */
    file->column_bitmaps_signal();
  }
  DBUG_VOID_RETURN;
}


/*
  Mark that only fields from one key is used

  NOTE:
    This changes the bitmap to use the tmp bitmap
    After this, you can't access any other columns in the table until
    bitmaps are reset, for example with TABLE::clear_column_bitmaps()
    or TABLE::restore_column_maps_after_mark_index()
*/

void TABLE::mark_columns_used_by_index(uint index)
{
  MY_BITMAP *bitmap= &tmp_set;
  DBUG_ENTER("TABLE::mark_columns_used_by_index");

  enable_keyread();
  bitmap_clear_all(bitmap);
  mark_columns_used_by_index_no_reset(index, bitmap);
  column_bitmaps_set(bitmap, bitmap);
  DBUG_VOID_RETURN;
}


/*
  Add fields used by a specified index to the table's read_set.

  NOTE:
    The original state can be restored with
    restore_column_maps_after_mark_index().
*/

void TABLE::add_read_columns_used_by_index(uint index)
{
  MY_BITMAP *bitmap= &tmp_set;
  DBUG_ENTER("TABLE::add_read_columns_used_by_index");

  enable_keyread();
  bitmap_copy(bitmap, read_set);
  mark_columns_used_by_index_no_reset(index, bitmap);
  column_bitmaps_set(bitmap, write_set);
  DBUG_VOID_RETURN;
}


/*
  Restore to use normal column maps after key read

  NOTES
    This reverse the change done by mark_columns_used_by_index

  WARNING
    For this to work, one must have the normal table maps in place
    when calling mark_columns_used_by_index
*/

void TABLE::restore_column_maps_after_mark_index()
{
  DBUG_ENTER("TABLE::restore_column_maps_after_mark_index");

  disable_keyread();
  default_column_bitmaps();
  file->column_bitmaps_signal();
  DBUG_VOID_RETURN;
}


/*
  mark columns used by key, but don't reset other fields
*/

void TABLE::mark_columns_used_by_index_no_reset(uint index,
                                                   MY_BITMAP *bitmap)
{
  KEY_PART_INFO *key_part= key_info[index].key_part;
  KEY_PART_INFO *key_part_end= (key_part +
                                key_info[index].key_parts);
  for (;key_part != key_part_end; key_part++)
  {
    bitmap_set_bit(bitmap, key_part->fieldnr-1);
    if (key_part->field->vcol_info &&
        key_part->field->vcol_info->expr_item)
      key_part->field->vcol_info->
               expr_item->walk(&Item::register_field_in_bitmap, 
                               1, (uchar *) bitmap);
  }
}


/*
  Mark auto-increment fields as used fields in both read and write maps

  NOTES
    This is needed in insert & update as the auto-increment field is
    always set and sometimes read.
*/

void TABLE::mark_auto_increment_column()
{
  DBUG_ASSERT(found_next_number_field);
  /*
    We must set bit in read set as update_auto_increment() is using the
    store() to check overflow of auto_increment values
  */
  bitmap_set_bit(read_set, found_next_number_field->field_index);
  bitmap_set_bit(write_set, found_next_number_field->field_index);
  if (s->next_number_keypart)
    mark_columns_used_by_index_no_reset(s->next_number_index, read_set);
  file->column_bitmaps_signal();
}


/*
  Mark columns needed for doing an delete of a row

  DESCRIPTON
    Some table engines don't have a cursor on the retrieve rows
    so they need either to use the primary key or all columns to
    be able to delete a row.

    If the engine needs this, the function works as follows:
    - If primary key exits, mark the primary key columns to be read.
    - If not, mark all columns to be read

    If the engine has HA_REQUIRES_KEY_COLUMNS_FOR_DELETE, we will
    mark all key columns as 'to-be-read'. This allows the engine to
    loop over the given record to find all keys and doesn't have to
    retrieve the row again.
*/

void TABLE::mark_columns_needed_for_delete()
{
  if (triggers)
    triggers->mark_fields_used(TRG_EVENT_DELETE);
  if (file->ha_table_flags() & HA_REQUIRES_KEY_COLUMNS_FOR_DELETE)
  {
    Field **reg_field;
    for (reg_field= field ; *reg_field ; reg_field++)
    {
      if ((*reg_field)->flags & PART_KEY_FLAG)
        bitmap_set_bit(read_set, (*reg_field)->field_index);
    }
    file->column_bitmaps_signal();
  }
  if (file->ha_table_flags() & HA_PRIMARY_KEY_REQUIRED_FOR_DELETE)
  {
    /*
      If the handler has no cursor capabilites, we have to read either
      the primary key, the hidden primary key or all columns to be
      able to do an delete
    */
    if (s->primary_key == MAX_KEY)
      file->use_hidden_primary_key();
    else
    {
      mark_columns_used_by_index_no_reset(s->primary_key, read_set);
      file->column_bitmaps_signal();
    }
  }
}


/*
  Mark columns needed for doing an update of a row

  DESCRIPTON
    Some engines needs to have all columns in an update (to be able to
    build a complete row). If this is the case, we mark all not
    updated columns to be read.

    If this is no the case, we do like in the delete case and mark
    if neeed, either the primary key column or all columns to be read.
    (see mark_columns_needed_for_delete() for details)

    If the engine has HA_REQUIRES_KEY_COLUMNS_FOR_DELETE, we will
    mark all USED key columns as 'to-be-read'. This allows the engine to
    loop over the given record to find all changed keys and doesn't have to
    retrieve the row again.
*/

void TABLE::mark_columns_needed_for_update()
{
  DBUG_ENTER("mark_columns_needed_for_update");
  if (triggers)
    triggers->mark_fields_used(TRG_EVENT_UPDATE);
  if (file->ha_table_flags() & HA_REQUIRES_KEY_COLUMNS_FOR_DELETE)
  {
    /* Mark all used key columns for read */
    Field **reg_field;
    for (reg_field= field ; *reg_field ; reg_field++)
    {
      /* Merge keys is all keys that had a column refered to in the query */
      if (merge_keys.is_overlapping((*reg_field)->part_of_key))
        bitmap_set_bit(read_set, (*reg_field)->field_index);
    }
    file->column_bitmaps_signal();
  }
  if (file->ha_table_flags() & HA_PRIMARY_KEY_REQUIRED_FOR_DELETE)
  {
    /*
      If the handler has no cursor capabilites, we have to read either
      the primary key, the hidden primary key or all columns to be
      able to do an update
    */
    if (s->primary_key == MAX_KEY)
      file->use_hidden_primary_key();
    else
    {
      mark_columns_used_by_index_no_reset(s->primary_key, read_set);
      file->column_bitmaps_signal();
    }
  }
  /* Mark all virtual columns needed for update */
  mark_virtual_columns_for_write(FALSE);
  DBUG_VOID_RETURN;
}


/*
  Mark columns the handler needs for doing an insert

  For now, this is used to mark fields used by the trigger
  as changed.
*/

void TABLE::mark_columns_needed_for_insert()
{
  if (triggers)
  {
    /*
      We don't need to mark columns which are used by ON DELETE and
      ON UPDATE triggers, which may be invoked in case of REPLACE or
      INSERT ... ON DUPLICATE KEY UPDATE, since before doing actual
      row replacement or update write_record() will mark all table
      fields as used.
    */
    triggers->mark_fields_used(TRG_EVENT_INSERT);
  }
  if (found_next_number_field)
    mark_auto_increment_column();
  /* Mark virtual columns for insert */
  mark_virtual_columns_for_write(TRUE);
}


/*
   @brief Mark a column as virtual used by the query

   @param field           the field for the column to be marked

   @details
     The function marks the column for 'field' as virtual (computed)
     in the bitmap vcol_set.
     If the column is marked for the first time the expression to compute
     the column is traversed and all columns that are occurred there are
     marked in the read_set of the table.

   @retval
     TRUE       if column is marked for the first time
   @retval
     FALSE      otherwise
*/

bool TABLE::mark_virtual_col(Field *field)
{
  bool res;
  DBUG_ASSERT(field->vcol_info);
  if (!(res= bitmap_fast_test_and_set(vcol_set, field->field_index)))
  {
    Item *vcol_item= field->vcol_info->expr_item;
    DBUG_ASSERT(vcol_item);
    vcol_item->walk(&Item::register_field_in_read_map, 1, (uchar *) 0);
  }
  return res;
}


/* 
  @brief Mark virtual columns for update/insert commands
    
  @param insert_fl    <-> virtual columns are marked for insert command 

  @details
    The function marks virtual columns used in a update/insert commands
    in the vcol_set bitmap.
    For an insert command a virtual column is always marked in write_set if
    it is a stored column.
    If a virtual column is from  write_set it is always marked in vcol_set.
    If a stored virtual column is not from write_set but it is computed
    through columns from write_set it is also marked in vcol_set, and,
    besides, it is added to write_set. 

  @return       void

  @note
    Let table t1 have columns a,b,c and let column c be a stored virtual 
    column computed through columns a and b. Then for the query
      UPDATE t1 SET a=1
    column c will be placed into vcol_set and into write_set while
    column b will be placed into read_set.
    If column c was a virtual column, but not a stored virtual column
    then it would not be added to any of the sets. Column b would not
    be added to read_set either.           
*/

void TABLE::mark_virtual_columns_for_write(bool insert_fl)
{
  Field **vfield_ptr, *tmp_vfield;
  bool bitmap_updated= FALSE;

  if (!vfield)
    return;

  if (!vfield)
    return;

  for (vfield_ptr= vfield; *vfield_ptr; vfield_ptr++)
  {
    tmp_vfield= *vfield_ptr;
    if (bitmap_is_set(write_set, tmp_vfield->field_index))
      bitmap_updated= mark_virtual_col(tmp_vfield);
    else if (tmp_vfield->stored_in_db)
    {
      bool mark_fl= insert_fl;
      if (!mark_fl)
      {
        MY_BITMAP *save_read_set;
        Item *vcol_item= tmp_vfield->vcol_info->expr_item;
        DBUG_ASSERT(vcol_item);
        bitmap_clear_all(&tmp_set);
        save_read_set= read_set;
        read_set= &tmp_set;
        vcol_item->walk(&Item::register_field_in_read_map, 1, (uchar *) 0);
        read_set= save_read_set;
        bitmap_intersect(&tmp_set, write_set);
        mark_fl= !bitmap_is_clear_all(&tmp_set);
      }
      if (mark_fl)
      {
        bitmap_set_bit(write_set, tmp_vfield->field_index);
        mark_virtual_col(tmp_vfield);
        bitmap_updated= TRUE;
      }
    } 
  }
  if (bitmap_updated)
    file->column_bitmaps_signal();
}


/**
  Check if a table has a default function either for INSERT or UPDATE-like
  operation
  @retval true  there is a default function
  @retval false there is no default function
*/

bool TABLE::has_default_function(bool is_update)
{
  Field **dfield_ptr, *dfield;
  bool res= false;
  for (dfield_ptr= default_field; *dfield_ptr; dfield_ptr++)
  {
    dfield= (*dfield_ptr);
    if (is_update)
      res= dfield->has_update_default_function();
    else
      res= dfield->has_insert_default_function();
    if (res)
      return res;
  }
  return res;
}


/**
  Add all fields that have a default function to the table write set.
*/

void TABLE::mark_default_fields_for_write()
{
  Field **dfield_ptr, *dfield;
  enum_sql_command cmd= in_use->lex->sql_command;
  for (dfield_ptr= default_field; *dfield_ptr; dfield_ptr++)
  {
    dfield= (*dfield_ptr);
    if (((sql_command_flags[cmd] & CF_INSERTS_DATA) &&
         dfield->has_insert_default_function()) ||
        ((sql_command_flags[cmd] & CF_UPDATES_DATA) &&
         dfield->has_update_default_function()))
      bitmap_set_bit(write_set, dfield->field_index);
  }
}


/**
  @brief
  Allocate space for keys

  @param key_count  number of keys to allocate additionally

  @details
  The function allocates memory  to fit additionally 'key_count' keys 
  for this table.

  @return FALSE   space was successfully allocated
  @return TRUE    an error occur
*/

bool TABLE::alloc_keys(uint key_count)
{
  key_info= (KEY*) alloc_root(&mem_root, sizeof(KEY)*(s->keys+key_count));
  if (s->keys)
    memmove(key_info, s->key_info, sizeof(KEY)*s->keys);
  s->key_info= key_info;
  max_keys= s->keys+key_count;
  return !(key_info);
}


void TABLE::create_key_part_by_field(KEY *keyinfo,
                                     KEY_PART_INFO *key_part_info,
                                     Field *field, uint fieldnr)
{   
  field->flags|= PART_KEY_FLAG;
  key_part_info->null_bit= field->null_bit;
  key_part_info->null_offset= (uint) (field->null_ptr -
                                      (uchar*) record[0]);
  key_part_info->field= field;
  key_part_info->fieldnr= fieldnr;
  key_part_info->offset= field->offset(record[0]);
  key_part_info->length=   (uint16) field->pack_length();
  keyinfo->key_length+= key_part_info->length;
  key_part_info->key_part_flag= 0;
  /* TODO:
    The below method of computing the key format length of the
    key part is a copy/paste from opt_range.cc, and table.cc.
    This should be factored out, e.g. as a method of Field.
    In addition it is not clear if any of the Field::*_length
    methods is supposed to compute the same length. If so, it
    might be reused.
  */
  key_part_info->store_length= key_part_info->length;

  if (field->real_maybe_null())
  {
    key_part_info->store_length+= HA_KEY_NULL_LENGTH;
    keyinfo->key_length+= HA_KEY_NULL_LENGTH;
  }
  if (field->type() == MYSQL_TYPE_BLOB || 
      field->type() == MYSQL_TYPE_GEOMETRY ||
      field->real_type() == MYSQL_TYPE_VARCHAR)
  {
    key_part_info->store_length+= HA_KEY_BLOB_LENGTH;
    keyinfo->key_length+= HA_KEY_BLOB_LENGTH; // ???
    key_part_info->key_part_flag|=
      field->type() == MYSQL_TYPE_BLOB ? HA_BLOB_PART: HA_VAR_LENGTH_PART;
  }

  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_VARTEXT1 ||
    (ha_base_keytype) key_part_info->type == HA_KEYTYPE_VARTEXT2) ?
    0 : FIELDFLAG_BINARY;
}


/**
  @brief
  Add one key to a temporary table

  @param key            the number of the key
  @param key_parts      number of components of the key
  @param next_field_no  the call-back function that returns the number of
                        the field used as the next component of the key
  @param arg            the argument for the above function
  @param unique         TRUE <=> it is a unique index

  @details
  The function adds a new key to the table that is assumed to be a temporary
  table. At each its invocation the call-back function must return
  the number of the field that is used as the next component of this key.

  @return FALSE is a success
  @return TRUE if a failure

*/

bool TABLE::add_tmp_key(uint key, uint key_parts,
                        uint (*next_field_no) (uchar *), uchar *arg,
                        bool unique)
{
  DBUG_ASSERT(key < max_keys);

  char buf[NAME_CHAR_LEN];
  KEY* keyinfo;
  Field **reg_field;
  uint i;
  bool key_start= TRUE;
  KEY_PART_INFO* key_part_info=
      (KEY_PART_INFO*) alloc_root(&mem_root, sizeof(KEY_PART_INFO)*key_parts);
  if (!key_part_info)
    return TRUE;
  keyinfo= key_info + key;
  keyinfo->key_part= key_part_info;
  keyinfo->usable_key_parts= keyinfo->key_parts = key_parts;
  keyinfo->ext_key_parts= keyinfo->key_parts;
  keyinfo->key_length=0;
  keyinfo->algorithm= HA_KEY_ALG_UNDEF;
  keyinfo->flags= HA_GENERATED_KEY;
  keyinfo->ext_key_flags= keyinfo->flags;
  keyinfo->is_statistics_from_stat_tables= FALSE;
  if (unique)
    keyinfo->flags|= HA_NOSAME;
  sprintf(buf, "key%i", key);
  if (!(keyinfo->name= strdup_root(&mem_root, buf)))
    return TRUE;
  keyinfo->rec_per_key= (ulong*) alloc_root(&mem_root,
                                            sizeof(ulong)*key_parts);
  if (!keyinfo->rec_per_key)
    return TRUE;
  bzero(keyinfo->rec_per_key, sizeof(ulong)*key_parts);
  keyinfo->read_stats= NULL;
  keyinfo->collected_stats= NULL;

  for (i= 0; i < key_parts; i++)
  {
    uint fld_idx= next_field_no(arg); 
    reg_field= field + fld_idx;
    if (key_start)
      (*reg_field)->key_start.set_bit(key);
    (*reg_field)->part_of_key.set_bit(key);
    create_key_part_by_field(keyinfo, key_part_info, *reg_field, fld_idx+1);
    key_start= FALSE;
    key_part_info++;
  }

  set_if_bigger(s->max_key_length, keyinfo->key_length);
  s->keys++;
  return FALSE;
}

/*
  @brief
  Drop all indexes except specified one.

  @param key_to_save the key to save

  @details
  Drop all indexes on this table except 'key_to_save'. The saved key becomes
  key #0. Memory occupied by key parts of dropped keys are freed.
  If the 'key_to_save' is negative then all keys are freed.
*/

void TABLE::use_index(int key_to_save)
{
  uint i= 1;
  DBUG_ASSERT(!created && key_to_save < (int)s->keys);
  if (key_to_save >= 0)
    /* Save the given key. */
    memmove(key_info, key_info + key_to_save, sizeof(KEY));
  else
    /* Drop all keys; */
    i= 0;

  s->keys= i;
}

/*
  Return TRUE if the table is filled at execution phase 
  
  (and so, the optimizer must not do anything that depends on the contents of
   the table, like range analysis or constant table detection)
*/

bool TABLE::is_filled_at_execution()
{ 
  /*
    pos_in_table_list == NULL for internal temporary tables because they
    do not have a corresponding table reference. Such tables are filled
    during execution.
  */
  return test(!pos_in_table_list ||
              pos_in_table_list->jtbm_subselect || 
              pos_in_table_list->is_active_sjm());
}


/**
  @brief
  Get actual number of key components

  @param keyinfo

  @details
  The function calculates actual number of key components, possibly including
  components of extended keys, taken into consideration by the optimizer for the
  key described by the parameter keyinfo.

  @return number of considered key components
*/ 

uint TABLE::actual_n_key_parts(KEY *keyinfo)
{
  return optimizer_flag(in_use, OPTIMIZER_SWITCH_EXTENDED_KEYS) ?
           keyinfo->ext_key_parts : keyinfo->key_parts;
}

 
/**
  @brief
  Get actual key flags for a table key 

  @param keyinfo

  @details
  The function finds out actual key flags taken into consideration by the
  optimizer for the key described by the parameter keyinfo.

  @return actual key flags
*/ 

ulong TABLE::actual_key_flags(KEY *keyinfo)
{
  return optimizer_flag(in_use, OPTIMIZER_SWITCH_EXTENDED_KEYS) ?
           keyinfo->ext_key_flags : keyinfo->flags;
} 


/*
  Cleanup this table for re-execution.

  SYNOPSIS
    TABLE_LIST::reinit_before_use()
*/

void TABLE_LIST::reinit_before_use(THD *thd)
{
  /*
    Reset old pointers to TABLEs: they are not valid since the tables
    were closed in the end of previous prepare or execute call.
  */
  table= 0;
  /* Reset is_schema_table_processed value(needed for I_S tables */
  schema_table_state= NOT_PROCESSED;

  TABLE_LIST *embedded; /* The table at the current level of nesting. */
  TABLE_LIST *parent_embedding= this; /* The parent nested table reference. */
  do
  {
    embedded= parent_embedding;
    if (embedded->prep_on_expr)
      embedded->on_expr= embedded->prep_on_expr->copy_andor_structure(thd);
    parent_embedding= embedded->embedding;
  }
  while (parent_embedding &&
         parent_embedding->nested_join->join_list.head() == embedded);

  mdl_request.ticket= NULL;
}


/*
  Return subselect that contains the FROM list this table is taken from

  SYNOPSIS
    TABLE_LIST::containing_subselect()
 
  RETURN
    Subselect item for the subquery that contains the FROM list
    this table is taken from if there is any
    0 - otherwise

*/

Item_subselect *TABLE_LIST::containing_subselect()
{    
  return (select_lex ? select_lex->master_unit()->item : 0);
}

/*
  Compiles the tagged hints list and fills up the bitmasks.

  SYNOPSIS
    process_index_hints()
      table         the TABLE to operate on.

  DESCRIPTION
    The parser collects the index hints for each table in a "tagged list" 
    (TABLE_LIST::index_hints). Using the information in this tagged list
    this function sets the members TABLE::keys_in_use_for_query,
    TABLE::keys_in_use_for_group_by, TABLE::keys_in_use_for_order_by,
    TABLE::force_index, TABLE::force_index_order,
    TABLE::force_index_group and TABLE::covering_keys.

    Current implementation of the runtime does not allow mixing FORCE INDEX
    and USE INDEX, so this is checked here. Then the FORCE INDEX list 
    (if non-empty) is appended to the USE INDEX list and a flag is set.

    Multiple hints of the same kind are processed so that each clause 
    is applied to what is computed in the previous clause.
    For example:
        USE INDEX (i1) USE INDEX (i2)
    is equivalent to
        USE INDEX (i1,i2)
    and means "consider only i1 and i2".
        
    Similarly
        USE INDEX () USE INDEX (i1)
    is equivalent to
        USE INDEX (i1)
    and means "consider only the index i1"

    It is OK to have the same index several times, e.g. "USE INDEX (i1,i1)" is
    not an error.
        
    Different kind of hints (USE/FORCE/IGNORE) are processed in the following
    order:
      1. All indexes in USE (or FORCE) INDEX are added to the mask.
      2. All IGNORE INDEX

    e.g. "USE INDEX i1, IGNORE INDEX i1, USE INDEX i1" will not use i1 at all
    as if we had "USE INDEX i1, USE INDEX i1, IGNORE INDEX i1".

    As an optimization if there is a covering index, and we have 
    IGNORE INDEX FOR GROUP/ORDER, and this index is used for the JOIN part, 
    then we have to ignore the IGNORE INDEX FROM GROUP/ORDER.

  RETURN VALUE
    FALSE                no errors found
    TRUE                 found and reported an error.
*/
bool TABLE_LIST::process_index_hints(TABLE *tbl)
{
  /* initialize the result variables */
  tbl->keys_in_use_for_query= tbl->keys_in_use_for_group_by= 
    tbl->keys_in_use_for_order_by= tbl->s->keys_in_use;

  /* index hint list processing */
  if (index_hints)
  {
    key_map index_join[INDEX_HINT_FORCE + 1];
    key_map index_order[INDEX_HINT_FORCE + 1];
    key_map index_group[INDEX_HINT_FORCE + 1];
    Index_hint *hint;
    int type;
    bool have_empty_use_join= FALSE, have_empty_use_order= FALSE, 
         have_empty_use_group= FALSE;
    List_iterator <Index_hint> iter(*index_hints);

    /* initialize temporary variables used to collect hints of each kind */
    for (type= INDEX_HINT_IGNORE; type <= INDEX_HINT_FORCE; type++)
    {
      index_join[type].clear_all();
      index_order[type].clear_all();
      index_group[type].clear_all();
    }

    /* iterate over the hints list */
    while ((hint= iter++))
    {
      uint pos;

      /* process empty USE INDEX () */
      if (hint->type == INDEX_HINT_USE && !hint->key_name.str)
      {
        if (hint->clause & INDEX_HINT_MASK_JOIN)
        {
          index_join[hint->type].clear_all();
          have_empty_use_join= TRUE;
        }
        if (hint->clause & INDEX_HINT_MASK_ORDER)
        {
          index_order[hint->type].clear_all();
          have_empty_use_order= TRUE;
        }
        if (hint->clause & INDEX_HINT_MASK_GROUP)
        {
          index_group[hint->type].clear_all();
          have_empty_use_group= TRUE;
        }
        continue;
      }

      /* 
        Check if an index with the given name exists and get his offset in 
        the keys bitmask for the table 
      */
      if (tbl->s->keynames.type_names == 0 ||
          (pos= find_type(&tbl->s->keynames, hint->key_name.str,
                          hint->key_name.length, 1)) <= 0)
      {
        my_error(ER_KEY_DOES_NOT_EXITS, MYF(0), hint->key_name.str, alias);
        return 1;
      }

      pos--;

      /* add to the appropriate clause mask */
      if (hint->clause & INDEX_HINT_MASK_JOIN)
        index_join[hint->type].set_bit (pos);
      if (hint->clause & INDEX_HINT_MASK_ORDER)
        index_order[hint->type].set_bit (pos);
      if (hint->clause & INDEX_HINT_MASK_GROUP)
        index_group[hint->type].set_bit (pos);
    }

    /* cannot mix USE INDEX and FORCE INDEX */
    if ((!index_join[INDEX_HINT_FORCE].is_clear_all() ||
         !index_order[INDEX_HINT_FORCE].is_clear_all() ||
         !index_group[INDEX_HINT_FORCE].is_clear_all()) &&
        (!index_join[INDEX_HINT_USE].is_clear_all() ||  have_empty_use_join ||
         !index_order[INDEX_HINT_USE].is_clear_all() || have_empty_use_order ||
         !index_group[INDEX_HINT_USE].is_clear_all() || have_empty_use_group))
    {
      my_error(ER_WRONG_USAGE, MYF(0), index_hint_type_name[INDEX_HINT_USE],
               index_hint_type_name[INDEX_HINT_FORCE]);
      return 1;
    }

    /* process FORCE INDEX as USE INDEX with a flag */
    if (!index_order[INDEX_HINT_FORCE].is_clear_all())
    {
      tbl->force_index_order= TRUE;
      index_order[INDEX_HINT_USE].merge(index_order[INDEX_HINT_FORCE]);
    }

    if (!index_group[INDEX_HINT_FORCE].is_clear_all())
    {
      tbl->force_index_group= TRUE;
      index_group[INDEX_HINT_USE].merge(index_group[INDEX_HINT_FORCE]);
    }

    /*
      TODO: get rid of tbl->force_index (on if any FORCE INDEX is specified) and
      create tbl->force_index_join instead.
      Then use the correct force_index_XX instead of the global one.
    */
    if (!index_join[INDEX_HINT_FORCE].is_clear_all() ||
        tbl->force_index_group || tbl->force_index_order)
    {
      tbl->force_index= TRUE;
      index_join[INDEX_HINT_USE].merge(index_join[INDEX_HINT_FORCE]);
    }

    /* apply USE INDEX */
    if (!index_join[INDEX_HINT_USE].is_clear_all() || have_empty_use_join)
      tbl->keys_in_use_for_query.intersect(index_join[INDEX_HINT_USE]);
    if (!index_order[INDEX_HINT_USE].is_clear_all() || have_empty_use_order)
      tbl->keys_in_use_for_order_by.intersect (index_order[INDEX_HINT_USE]);
    if (!index_group[INDEX_HINT_USE].is_clear_all() || have_empty_use_group)
      tbl->keys_in_use_for_group_by.intersect (index_group[INDEX_HINT_USE]);

    /* apply IGNORE INDEX */
    tbl->keys_in_use_for_query.subtract (index_join[INDEX_HINT_IGNORE]);
    tbl->keys_in_use_for_order_by.subtract (index_order[INDEX_HINT_IGNORE]);
    tbl->keys_in_use_for_group_by.subtract (index_group[INDEX_HINT_IGNORE]);
  }

  /* make sure covering_keys don't include indexes disabled with a hint */
  tbl->covering_keys.intersect(tbl->keys_in_use_for_query);
  return 0;
}


size_t max_row_length(TABLE *table, const uchar *data)
{
  TABLE_SHARE *table_s= table->s;
  size_t length= table_s->reclength + 2 * table_s->fields;
  uint *const beg= table_s->blob_field;
  uint *const end= beg + table_s->blob_fields;

  for (uint *ptr= beg ; ptr != end ; ++ptr)
  {
    Field_blob* const blob= (Field_blob*) table->field[*ptr];
    length+= blob->get_length((const uchar*)
                              (data + blob->offset(table->record[0]))) +
      HA_KEY_BLOB_LENGTH;
  }
  return length;
}


/**
   Helper function which allows to allocate metadata lock request
   objects for all elements of table list.
*/

void init_mdl_requests(TABLE_LIST *table_list)
{
  for ( ; table_list ; table_list= table_list->next_global)
    table_list->mdl_request.init(MDL_key::TABLE,
                                 table_list->db, table_list->table_name,
                                 table_list->lock_type >= TL_WRITE_ALLOW_WRITE ?
                                 MDL_SHARED_WRITE : MDL_SHARED_READ,
                                 MDL_TRANSACTION);
}


/**
  Update TABLE::const_key_parts for single table UPDATE/DELETE query

  @param conds               WHERE clause expression

  @retval TRUE   error (OOM)
  @retval FALSE  success

  @note
    Set const_key_parts bits if key fields are equal to constants in
    the WHERE expression.
*/

bool TABLE::update_const_key_parts(COND *conds)
{
  bzero((char*) const_key_parts, sizeof(key_part_map) * s->keys);

  if (conds == NULL)
    return FALSE;

  for (uint index= 0; index < s->keys; index++)
  {
    KEY_PART_INFO *keyinfo= key_info[index].key_part;
    KEY_PART_INFO *keyinfo_end= keyinfo + key_info[index].key_parts;

    for (key_part_map part_map= (key_part_map)1; 
        keyinfo < keyinfo_end;
        keyinfo++, part_map<<= 1)
    {
      if (const_expression_in_where(conds, NULL, keyinfo->field))
        const_key_parts[index]|= part_map;
    }
  }
  return FALSE;
}

/**
  Test if the order list consists of simple field expressions

  @param order                Linked list of ORDER BY arguments

  @return TRUE if @a order is empty or consist of simple field expressions
*/

bool is_simple_order(ORDER *order)
{
  for (ORDER *ord= order; ord; ord= ord->next)
  {
    if (ord->item[0]->real_item()->type() != Item::FIELD_ITEM)
      return FALSE;
  }
  return TRUE;
}

/*
  @brief Compute values for virtual columns used in query

  @param  thd              Thread handle
  @param  table            The TABLE object
  @param  vcol_update_mode Specifies what virtual column are computed   
  
  @details
    The function computes the values of the virtual columns of the table and
    stores them in the table record buffer.
    If vcol_update_mode is set to VCOL_UPDATE_ALL then all virtual column are
    computed. Otherwise, only fields from vcol_set are computed: all of them,
    if vcol_update_mode is set to VCOL_UPDATE_FOR_WRITE, and, only those with
    the stored_in_db flag set to false, if vcol_update_mode is equal to
    VCOL_UPDATE_FOR_READ.

  @retval
    0    Success
  @retval
    >0   Error occurred when storing a virtual field value
*/

int update_virtual_fields(THD *thd, TABLE *table,
                          enum enum_vcol_update_mode vcol_update_mode)
{
  DBUG_ENTER("update_virtual_fields");
  Field **vfield_ptr, *vfield;
  int error __attribute__ ((unused))= 0;
  DBUG_ASSERT(table && table->vfield);

  thd->reset_arena_for_cached_items(table->expr_arena);
  /* Iterate over virtual fields in the table */
  for (vfield_ptr= table->vfield; *vfield_ptr; vfield_ptr++)
  {
    vfield= (*vfield_ptr);
    DBUG_ASSERT(vfield->vcol_info && vfield->vcol_info->expr_item);
    if ((bitmap_is_set(table->vcol_set, vfield->field_index) &&
         (vcol_update_mode == VCOL_UPDATE_FOR_WRITE || !vfield->stored_in_db)) ||
        vcol_update_mode == VCOL_UPDATE_ALL)
    {
      /* Compute the actual value of the virtual fields */
      error= vfield->vcol_info->expr_item->save_in_field(vfield, 0);
      DBUG_PRINT("info", ("field '%s' - updated", vfield->field_name));
    }
    else
    {
      DBUG_PRINT("info", ("field '%s' - skipped", vfield->field_name));
    }
  }
  thd->reset_arena_for_cached_items(0);
  DBUG_RETURN(0);
}


/**
  Update all DEFAULT and/or ON INSERT fields.

  @details
    Compute and set the default value of all fields with a default function.
    There are two kinds of default functions - one is used for INSERT-like
    operations, the other for UPDATE-like operations. Depending on the field
    definition and the current operation one or the other kind of update
    function is evaluated.

  @retval
    0    Success
  @retval
    >0   Error occurred when storing a virtual field value
*/

int TABLE::update_default_fields()
{
  DBUG_ENTER("update_default_fields");
  Field **dfield_ptr, *dfield;
  int res= 0;
  enum_sql_command cmd= in_use->lex->sql_command;

  DBUG_ASSERT(default_field);

  /* Iterate over virtual fields in the table */
  for (dfield_ptr= default_field; *dfield_ptr; dfield_ptr++)
  {
    dfield= (*dfield_ptr);
    /*
      If an explicit default value for a filed overrides the default,
      do not update the field with its automatic default value.
    */
    if (!(dfield->flags & HAS_EXPLICIT_VALUE))
    {
      if (sql_command_flags[cmd] & CF_INSERTS_DATA)
        res= dfield->evaluate_insert_default_function();
      if (sql_command_flags[cmd] & CF_UPDATES_DATA)
        res= dfield->evaluate_update_default_function();
      if (res)
        DBUG_RETURN(res);
    }
    /* Unset the explicit default flag for the next record. */
    dfield->flags&= ~HAS_EXPLICIT_VALUE;
  }
  DBUG_RETURN(res);
}


/*
  @brief Reset const_table flag

  @detail
  Reset const_table flag for this table. If this table is a merged derived
  table/view the flag is recursively reseted for all tables of the underlying
  select.
*/

void TABLE_LIST::reset_const_table()
{
  table->const_table= 0;
  if (is_merged_derived())
  {
    SELECT_LEX *select_lex= get_unit()->first_select();
    TABLE_LIST *tl;
    List_iterator<TABLE_LIST> ti(select_lex->leaf_tables);
    while ((tl= ti++))
      tl->reset_const_table();
  }
}


/*
  @brief Run derived tables/view handling phases on underlying select_lex.

  @param lex    LEX for this thread
  @param phases derived tables/views handling phases to run
                (set of DT_XXX constants)
  @details
  This function runs this derived table through specified 'phases'.
  Underlying tables of this select are handled prior to this derived.
  'lex' is passed as an argument to called functions.

  @return TRUE on error
  @return FALSE ok
*/

bool TABLE_LIST::handle_derived(LEX *lex, uint phases)
{
  SELECT_LEX_UNIT *unit= get_unit();
  if (unit)
  {
    for (SELECT_LEX *sl= unit->first_select(); sl; sl= sl->next_select())
      if (sl->handle_derived(lex, phases))
        return TRUE;
    return mysql_handle_single_derived(lex, this, phases);
  }
  return FALSE;
}


/**
  @brief
  Return unit of this derived table/view

  @return reference to a unit  if it's a derived table/view.
  @return 0                    when it's not a derived table/view.
*/

st_select_lex_unit *TABLE_LIST::get_unit()
{
  return (view ? &view->unit : derived);
}


/**
  @brief
  Return select_lex of this derived table/view

  @return select_lex of this derived table/view.
  @return 0          when it's not a derived table.
*/

st_select_lex *TABLE_LIST::get_single_select()
{
  SELECT_LEX_UNIT *unit= get_unit();
  return (unit ? unit->first_select() : 0);
}


/**
  @brief
  Attach a join table list as a nested join to this TABLE_LIST.

  @param join_list join table list to attach

  @details
  This function wraps 'join_list' into a nested_join of this table, thus
  turning it to a nested join leaf.
*/

void TABLE_LIST::wrap_into_nested_join(List<TABLE_LIST> &join_list)
{
  TABLE_LIST *tl;
  /*
    Walk through derived table top list and set 'embedding' to point to
    the nesting table.
  */
  nested_join->join_list.empty();
  List_iterator_fast<TABLE_LIST> li(join_list);
  nested_join->join_list= join_list;
  while ((tl= li++))
  {
    tl->embedding= this;
    tl->join_list= &nested_join->join_list;
  }
}


/**
  @brief
  Initialize this derived table/view

  @param thd  Thread handle

  @details
  This function makes initial preparations of this derived table/view for
  further processing:
    if it's a derived table this function marks it either as mergeable or
      materializable
    creates temporary table for name resolution purposes
    creates field translation for mergeable derived table/view

  @return TRUE  an error occur
  @return FALSE ok
*/

bool TABLE_LIST::init_derived(THD *thd, bool init_view)
{
  SELECT_LEX *first_select= get_single_select();
  SELECT_LEX_UNIT *unit= get_unit();

  if (!unit)
    return FALSE;
  /*
    Check whether we can merge this derived table into main select.
    Depending on the result field translation will or will not
    be created.
  */
  TABLE_LIST *first_table= (TABLE_LIST *) first_select->table_list.first;
  if (first_select->table_list.elements > 1 ||
      (first_table && first_table->is_multitable()))
    set_multitable();

  unit->derived= this;
  if (init_view && !view)
  {
    /* This is all what we can do for a derived table for now. */
    set_derived();
  }

  if (!is_view())
  {
    /* A subquery might be forced to be materialized due to a side-effect. */
    if (!is_materialized_derived() && first_select->is_mergeable() &&
        optimizer_flag(thd, OPTIMIZER_SWITCH_DERIVED_MERGE) &&
        !(thd->lex->sql_command == SQLCOM_UPDATE_MULTI ||
          thd->lex->sql_command == SQLCOM_DELETE_MULTI))
      set_merged_derived();
    else
      set_materialized_derived();
  }
  /*
    Derived tables/view are materialized prior to UPDATE, thus we can skip
    them from table uniqueness check
  */
  if (is_materialized_derived())
  {
    set_check_materialized();
  }

  /*
    Create field translation for mergeable derived tables/views.
    For derived tables field translation can be created only after
    unit is prepared so all '*' are get unrolled.
  */
  if (is_merged_derived())
  {
    if (is_view() || unit->prepared)
      create_field_translation(thd);
  }

  return FALSE;
}


/**
  @brief
  Retrieve number of rows in the table

  @details
  Retrieve number of rows in the table referred by this TABLE_LIST and
  store it in the table's stats.records variable. If this TABLE_LIST refers
  to a materialized derived table/view then the estimated number of rows of
  the derived table/view is used instead.

  @return 0          ok
  @return non zero   error
*/

int TABLE_LIST::fetch_number_of_rows()
{
  int error= 0;
  if (jtbm_subselect)
    return 0;
  if (is_materialized_derived() && !fill_me)

  {
    table->file->stats.records= ((select_union*)derived->result)->records;
    set_if_bigger(table->file->stats.records, 2);
    table->used_stat_records= table->file->stats.records;
  }
  else
    error= table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);
  return error;
}

/*
  Procedure of keys generation for result tables of materialized derived
  tables/views.

  A key is generated for each equi-join pair derived table-another table.
  Each generated key consists of fields of derived table used in equi-join.
  Example:

    SELECT * FROM (SELECT * FROM t1 GROUP BY 1) tt JOIN
                  t1 ON tt.f1=t1.f3 and tt.f2.=t1.f4;
  In this case for the derived table tt one key will be generated. It will
  consist of two parts f1 and f2.
  Example:

    SELECT * FROM (SELECT * FROM t1 GROUP BY 1) tt JOIN
                  t1 ON tt.f1=t1.f3 JOIN
                  t2 ON tt.f2=t2.f4;
  In this case for the derived table tt two keys will be generated.
  One key over f1 field, and another key over f2 field.
  Currently optimizer may choose to use only one such key, thus the second
  one will be dropped after range optimizer is finished.
  See also JOIN::drop_unused_derived_keys function.
  Example:

    SELECT * FROM (SELECT * FROM t1 GROUP BY 1) tt JOIN
                  t1 ON tt.f1=a_function(t1.f3);
  In this case for the derived table tt one key will be generated. It will
  consist of one field - f1.
*/



/*
  @brief
  Change references to underlying items of a merged derived table/view
  for fields in derived table's result table.

  @return FALSE ok
  @return TRUE  Out of memory
*/
bool TABLE_LIST::change_refs_to_fields()
{
  List_iterator<Item> li(used_items);
  Item_direct_ref *ref;
  Field_iterator_view field_it;
  THD *thd= table->in_use;
  DBUG_ASSERT(is_merged_derived());

  if (!used_items.elements)
    return FALSE;

  materialized_items= (Item**)thd->calloc(sizeof(void*) * table->s->fields);

  while ((ref= (Item_direct_ref*)li++))
  {
    uint idx;
    Item *orig_item= *ref->ref;
    field_it.set(this);
    for (idx= 0; !field_it.end_of_fields(); field_it.next(), idx++)
    {
      if (field_it.item() == orig_item)
        break;
    }
    DBUG_ASSERT(!field_it.end_of_fields());
    if (!materialized_items[idx])
    {
      materialized_items[idx]= new Item_field(table->field[idx]);
      if (!materialized_items[idx])
        return TRUE;
    }
    /*
      We need to restore the pointers after the execution of the
      prepared statement.
    */
    thd->change_item_tree((Item **)&ref->ref,
                          (Item*)(materialized_items + idx));
  }

  return FALSE;
}


uint TABLE_SHARE::actual_n_key_parts(THD *thd)
{
  return use_ext_keys &&
         optimizer_flag(thd, OPTIMIZER_SWITCH_EXTENDED_KEYS) ?
           ext_key_parts : key_parts;
}  


double KEY::actual_rec_per_key(uint i)
{ 
  if (rec_per_key == 0)
    return 0;
  return (is_statistics_from_stat_tables ?
          read_stats->get_avg_frequency(i) : (double) rec_per_key[i]);
}