handler.cc

/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */


/* Handler-calling-functions */

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

#include "mysql_priv.h"
#include "ha_heap.h"
#include "ha_myisam.h"
#include "ha_myisammrg.h"
#ifndef NO_ISAM
#include "ha_isam.h"
#include "ha_isammrg.h"
#endif
#ifdef HAVE_BERKELEY_DB
#include "ha_berkeley.h"
#endif
#ifdef HAVE_INNOBASE_DB
#include "ha_innobase.h"
#endif
#ifdef HAVE_GEMINI_DB
#include "ha_gemini.h"
#endif
#include <myisampack.h>
#include <errno.h>

	/* static functions defined in this file */

static int NEAR_F delete_file(const char *name,const char *ext,int extflag);

ulong ha_read_count, ha_write_count, ha_delete_count, ha_update_count,
      ha_read_key_count, ha_read_next_count, ha_read_prev_count,
      ha_read_first_count, ha_read_last_count,
      ha_read_rnd_count, ha_read_rnd_next_count;

const char *ha_table_type[] = {
  "", "DIAB_ISAM","HASH","MISAM","PISAM","RMS_ISAM","HEAP", "ISAM",
  "MRG_ISAM","MYISAM", "MRG_MYISAM", "BDB", "INNOBASE", "GEMINI", "?", "?",NullS
};

TYPELIB ha_table_typelib= {array_elements(ha_table_type)-4,"",
			   ha_table_type+1};

const char *ha_row_type[] = {
  "", "FIXED", "DYNAMIC", "COMPRESSED","?","?","?"
};

const char *tx_isolation_names[] =
{ "READ-UNCOMMITTED", "READ-COMMITTED", "REPEATABLE-READ", "SERIALIZABLE",
  NullS};
TYPELIB tx_isolation_typelib= {array_elements(tx_isolation_names)-1,"",
			       tx_isolation_names};

	/* Use other database handler if databasehandler is not incompiled */

enum db_type ha_checktype(enum db_type database_type)
{
  switch (database_type) {
#ifdef HAVE_BERKELEY_DB
  case DB_TYPE_BERKELEY_DB:
    return(berkeley_skip ? DB_TYPE_MYISAM : database_type);
#endif
#ifdef HAVE_INNOBASE_DB
  case DB_TYPE_INNOBASE:
    return(innodb_skip ? DB_TYPE_MYISAM : database_type);
#endif
#ifdef HAVE_GEMINI_DB
  case DB_TYPE_GEMINI:
    return(gemini_skip ? DB_TYPE_MYISAM : database_type);
#endif
#ifndef NO_HASH
  case DB_TYPE_HASH:
#endif
#ifndef NO_MERGE
  case DB_TYPE_MRG_ISAM:
#endif
#ifndef NO_ISAM
  case DB_TYPE_ISAM:
#endif
  case DB_TYPE_HEAP:
  case DB_TYPE_MYISAM:
  case DB_TYPE_MRG_MYISAM:
    return (database_type);			/* Database exists on system */
  default:
    break;
  }
  return(DB_TYPE_MYISAM);			/* Use this as default */
} /* ha_checktype */


handler *get_new_handler(TABLE *table, enum db_type db_type)
{
  switch (db_type) {
#ifndef NO_HASH
  return new ha_hash(table);
#endif
#ifndef NO_MERGE
  case DB_TYPE_MRG_ISAM:
    return new ha_isammrg(table);
#endif
#ifndef NO_ISAM
  case DB_TYPE_ISAM:
    return new ha_isam(table);
#endif
#ifdef HAVE_BERKELEY_DB
  case DB_TYPE_BERKELEY_DB:
    return new ha_berkeley(table);
#endif
#ifdef HAVE_INNOBASE_DB
  case DB_TYPE_INNOBASE:
    return new ha_innobase(table);
#endif
#ifdef HAVE_GEMINI_DB
  case DB_TYPE_GEMINI:
    return new ha_gemini(table);
#endif
  case DB_TYPE_HEAP:
    return new ha_heap(table);
  case DB_TYPE_MYISAM:
  default:					// should never happen
    return new ha_myisam(table);
  case DB_TYPE_MRG_MYISAM:
    return new ha_myisammrg(table);
  }
}

int ha_init()
{
#ifdef HAVE_BERKELEY_DB
  if (!berkeley_skip)
  {
    int error;
    if ((error=berkeley_init()))
      return error;
    if (!berkeley_skip)				// If we couldn't use handler
      opt_using_transactions=1;
    else
      have_berkeley_db=SHOW_OPTION_DISABLED;
  }
#endif
#ifdef HAVE_INNOBASE_DB
  if (!innodb_skip)
  {
    if (innobase_init())
      return -1;
    if (!innodb_skip)				// If we couldn't use handler
      opt_using_transactions=1;
    else
      have_innodb=SHOW_OPTION_DISABLED;
  }
#endif
#ifdef HAVE_GEMINI_DB
  if (!gemini_skip)
  {
    if (gemini_init())
      return -1;
    if (!gemini_skip)				// If we couldn't use handler
      opt_using_transactions=1;
    else
      have_gemini=SHOW_OPTION_DISABLED;
  }
#endif
  return 0;
}

	/* close, flush or restart databases */
	/* Ignore this for other databases than ours */

int ha_panic(enum ha_panic_function flag)
{
  int error=0;
#ifndef NO_MERGE
  error|=mrg_panic(flag);
#endif
#ifndef NO_HASH
  error|=h_panic(flag);			/* fix hash */
#endif
  error|=heap_panic(flag);
  error|=nisam_panic(flag);
  error|=mi_panic(flag);
  error|=myrg_panic(flag);
#ifdef HAVE_BERKELEY_DB
  if (!berkeley_skip)
    error|=berkeley_end();
#endif
#ifdef HAVE_INNOBASE_DB
  if (!innodb_skip)
    error|=innobase_end();
#endif
#ifdef HAVE_GEMINI_DB
  if (!gemini_skip)
    error|=gemini_end();
#endif
  return error;
} /* ha_panic */


void ha_close_connection(THD* thd)
{
#ifdef HAVE_INNOBASE_DB
  if (!innodb_skip)
    innobase_close_connection(thd);
#endif
#ifdef HAVE_GEMINI_DB
  if (!gemini_skip && thd->gemini.context)
  {
    gemini_disconnect(thd);
  }
#endif /* HAVE_GEMINI_DB */
}

/*
  This is used to commit or rollback a single statement depending
  on the value of error
*/

int ha_autocommit_or_rollback(THD *thd, int error)
{
  DBUG_ENTER("ha_autocommit_or_rollback");
#ifdef USING_TRANSACTIONS
  if (opt_using_transactions)
  {
    if (!error)
    {
      if (ha_commit_stmt(thd))
	error=1;
    }
    else
      (void) ha_rollback_stmt(thd);
    thd->tx_isolation=thd->session_tx_isolation;
  }
#endif
  DBUG_RETURN(error);
}


int ha_commit_trans(THD *thd, THD_TRANS* trans)
{
  int error=0;
  DBUG_ENTER("ha_commit");
#ifdef USING_TRANSACTIONS
  if (opt_using_transactions)
  {
    /* Update the binary log if we have cached some queries */
    if (trans == &thd->transaction.all && mysql_bin_log.is_open() &&
	my_b_tell(&thd->transaction.trans_log))
    {
      mysql_bin_log.write(&thd->transaction.trans_log);
      reinit_io_cache(&thd->transaction.trans_log,
		      WRITE_CACHE, (my_off_t) 0, 0, 1);
      thd->transaction.trans_log.end_of_file= max_binlog_cache_size;
    }
#ifdef HAVE_BERKELEY_DB
    if (trans->bdb_tid)
    {
      if ((error=berkeley_commit(thd,trans->bdb_tid)))
      {
	my_error(ER_ERROR_DURING_COMMIT, MYF(0), error);
	error=1;
      }
      trans->bdb_tid=0;
    }
#endif
#ifdef HAVE_INNOBASE_DB
    if (trans->innobase_tid)
    {
      if ((error=innobase_commit(thd,trans->innobase_tid)))
      {
	my_error(ER_ERROR_DURING_COMMIT, MYF(0), error);
	error=1;
      }
    }
#endif
#ifdef HAVE_GEMINI_DB 
    /* Commit the transaction in behalf of the commit statement
       or if we're in auto-commit mode               */
    if((trans == &thd->transaction.all) || 
        (!(thd->options & (OPTION_NOT_AUTO_COMMIT | OPTION_BEGIN))))
    {
      error=gemini_commit(thd);
      if (error)
      {
	my_error(ER_ERROR_DURING_COMMIT, MYF(0), error);
	error=1;
      }
    }
#endif
    if (error && trans == &thd->transaction.all && mysql_bin_log.is_open())
      sql_print_error("Error: Got error during commit;  Binlog is not up to date!");
    thd->tx_isolation=thd->session_tx_isolation;
  }
#endif // using transactions
  DBUG_RETURN(error);
}


int ha_rollback_trans(THD *thd, THD_TRANS *trans)
{
  int error=0;
  DBUG_ENTER("ha_rollback");
#ifdef USING_TRANSACTIONS
  if (opt_using_transactions)
  {
#ifdef HAVE_BERKELEY_DB
    if (trans->bdb_tid)
    {
      if ((error=berkeley_rollback(thd, trans->bdb_tid)))
      {
	my_error(ER_ERROR_DURING_ROLLBACK, MYF(0), error);
	error=1;
      }
      trans->bdb_tid=0;
    }
#endif
#ifdef HAVE_INNOBASE_DB
    if (trans->innobase_tid)
    {
      if ((error=innobase_rollback(thd, trans->innobase_tid)))
      {
	my_error(ER_ERROR_DURING_ROLLBACK, MYF(0), error);
	error=1;
      }
    }
#endif
#ifdef HAVE_GEMINI_DB
    if((trans == &thd->transaction.stmt) &&
       (thd->options & (OPTION_NOT_AUTO_COMMIT | OPTION_BEGIN)))
      error = gemini_rollback_to_savepoint(thd);
    else
      error=gemini_rollback(thd);
    if (error)
    {
      my_error(ER_ERROR_DURING_ROLLBACK, MYF(0), error);
      error=1;
    }
#endif
    if (trans == &thd->transaction.all)
      reinit_io_cache(&thd->transaction.trans_log,
		      WRITE_CACHE, (my_off_t) 0, 0, 1);
    thd->transaction.trans_log.end_of_file= max_binlog_cache_size;
    thd->tx_isolation=thd->session_tx_isolation;
  }
#endif /* USING_TRANSACTIONS */
  DBUG_RETURN(error);
}

void ha_set_spin_retries(uint retries)
{
#ifdef HAVE_GEMINI_DB
  if (!gemini_skip)
  {
    gemini_set_option_long(GEM_OPTID_SPIN_RETRIES, retries);
  }
#endif /* HAVE_GEMINI_DB */
}


bool ha_flush_logs()
{
  bool result=0;
#ifdef HAVE_BERKELEY_DB
  if (!berkeley_skip && berkeley_flush_logs())
    result=1;
#endif
#ifdef HAVE_INNOBASE_DB
  if (!innodb_skip && innobase_flush_logs())
    result=1;
#endif
  return result;
}

/*
  This should return ENOENT if the file doesn't exists.
  The .frm file will be deleted only if we return 0 or ENOENT
*/

int ha_delete_table(enum db_type table_type, const char *path)
{
  handler *file=get_new_handler((TABLE*) 0, table_type);
  if (!file)
    return ENOENT;
  int error=file->delete_table(path);
  delete file;
  return error;
}
    
void ha_store_ptr(byte *buff, uint pack_length, my_off_t pos)
{
  switch (pack_length) {
#if SIZEOF_OFF_T > 4
  case 8: mi_int8store(buff,pos); break;
  case 7: mi_int7store(buff,pos); break;
  case 6: mi_int6store(buff,pos); break;
  case 5: mi_int5store(buff,pos); break;
#endif
  case 4: mi_int4store(buff,pos); break;
  case 3: mi_int3store(buff,pos); break;
  case 2: mi_int2store(buff,(uint) pos); break;
  case 1: buff[0]= (uchar) pos; break;
  }
  return;
}

my_off_t ha_get_ptr(byte *ptr, uint pack_length)
{
  my_off_t pos;
  switch (pack_length) {
#if SIZEOF_OFF_T > 4
  case 8:
    pos= (my_off_t) mi_uint8korr(ptr);
    break;
  case 7:
    pos= (my_off_t) mi_uint7korr(ptr);
    break;
  case 6:
    pos= (my_off_t) mi_uint6korr(ptr);
    break;
  case 5:
    pos= (my_off_t) mi_uint5korr(ptr);
    break;
#endif
  case 4:
    pos= (my_off_t) mi_uint4korr(ptr);
    break;
  case 3:
    pos= (my_off_t) mi_uint3korr(ptr);
    break;
  case 2:
    pos= (my_off_t) mi_uint2korr(ptr);
    break;
  case 1:
    pos= (my_off_t) mi_uint2korr(ptr);
    break;
  default:
    pos=0;					// Impossible
    break;
  }
 return pos;
}

/****************************************************************************
** General handler functions
****************************************************************************/

	/* Open database-handler. Try O_RDONLY if can't open as O_RDWR */
	/* Don't wait for locks if not HA_OPEN_WAIT_IF_LOCKED is set */

int handler::ha_open(const char *name, int mode, int test_if_locked)
{
  int error;
  DBUG_ENTER("handler::open");
  DBUG_PRINT("enter",("name: %s  db_type: %d  db_stat: %d  mode: %d  lock_test: %d",
		      name, table->db_type, table->db_stat, mode, test_if_locked));

  if ((error=open(name,mode,test_if_locked)))
  {
    if ((error == EACCES || error == EROFS) && mode == O_RDWR &&
	(table->db_stat & HA_TRY_READ_ONLY))
    {
      table->db_stat|=HA_READ_ONLY;
      error=open(name,O_RDONLY,test_if_locked);
    }
  }
  if (error)
  {
    my_errno=error;			/* Safeguard */
    DBUG_PRINT("error",("error: %d  errno: %d",error,errno));
  }
  else
  {
    if (table->db_options_in_use & HA_OPTION_READ_ONLY_DATA)
      table->db_stat|=HA_READ_ONLY;
  }
  if (!error)
  {
    if (!alloc_root_inited(&table->mem_root))	// If temporary table
      ref=(byte*) sql_alloc(ALIGN_SIZE(ref_length)*2);
    else
      ref=(byte*) alloc_root(&table->mem_root, ALIGN_SIZE(ref_length)*2);
    if (!ref)
    {
      close();
      error=HA_ERR_OUT_OF_MEM;
    }
    else
      dupp_ref=ref+ALIGN_SIZE(ref_length);
  }
  DBUG_RETURN(error);
}

int handler::check(THD* thd, HA_CHECK_OPT* check_opt)
{
  return HA_ADMIN_NOT_IMPLEMENTED;
}

int handler::backup(THD* thd, HA_CHECK_OPT* check_opt)
{
  return HA_ADMIN_NOT_IMPLEMENTED;
}

int handler::restore(THD* thd, HA_CHECK_OPT* check_opt)
{
  return HA_ADMIN_NOT_IMPLEMENTED;
}

int handler::repair(THD* thd, HA_CHECK_OPT* check_opt)
{
  return HA_ADMIN_NOT_IMPLEMENTED;
}

int handler::optimize(THD* thd, HA_CHECK_OPT* check_opt)
{
  return HA_ADMIN_NOT_IMPLEMENTED;
}

int handler::analyze(THD* thd, HA_CHECK_OPT* check_opt)
{
  return HA_ADMIN_NOT_IMPLEMENTED;
}

	/* Read first row from a table */

int handler::rnd_first(byte * buf)
{
  register int error;
  DBUG_ENTER("handler::rnd_first");

  statistic_increment(ha_read_first_count,&LOCK_status);
  (void) rnd_init();
  while ((error= rnd_next(buf)) == HA_ERR_RECORD_DELETED) ;
  (void) rnd_end();
  DBUG_RETURN(error);
}


/*
  The following function is only needed for tables that may be temporary tables
  during joins
*/

int handler::restart_rnd_next(byte *buf, byte *pos)
{
  return HA_ERR_WRONG_COMMAND;
}


	/* Set a timestamp in record */

void handler::update_timestamp(byte *record)
{
  long skr= (long) current_thd->query_start();
#ifdef WORDS_BIGENDIAN
  if (table->db_low_byte_first)
  {
    int4store(record,skr);
  }
  else
#endif
  longstore(record,skr);
  return;
}

	/* Updates field with field_type NEXT_NUMBER according to following:
	** if field = 0 change field to the next free key in database.
	*/

void handler::update_auto_increment()
{
  longlong nr;
  THD *thd;
  DBUG_ENTER("update_auto_increment");
  if (table->next_number_field->val_int() != 0)
  {
    auto_increment_column_changed=0;
    DBUG_VOID_RETURN;
  }
  thd=current_thd;
  if ((nr=thd->next_insert_id))
    thd->next_insert_id=0;			// Clear after use
  else
    nr=get_auto_increment();
  thd->insert_id((ulonglong) nr);
  table->next_number_field->store(nr);
  auto_increment_column_changed=1;
  DBUG_VOID_RETURN;
}


longlong handler::get_auto_increment()
{
  longlong nr;
  int error;
  (void) extra(HA_EXTRA_KEYREAD);
  index_init(table->next_number_index);
  error=index_last(table->record[1]);
  if (error)
    nr=1;
  else
    nr=(longlong) table->next_number_field->
      val_int_offset(table->rec_buff_length)+1;
  (void) extra(HA_EXTRA_NO_KEYREAD);
  index_end();
  return nr;
}

	/* Print error that we got from handler function */

void handler::print_error(int error, myf errflag)
{
  DBUG_ENTER("print_error");
  DBUG_PRINT("enter",("error: %d",error));

  int textno=ER_GET_ERRNO;
  switch (error) {
  case EAGAIN:
    textno=ER_FILE_USED;
    break;
  case ENOENT:
    textno=ER_FILE_NOT_FOUND;
    break;
  case HA_ERR_KEY_NOT_FOUND:
  case HA_ERR_NO_ACTIVE_RECORD:
  case HA_ERR_END_OF_FILE:
    textno=ER_KEY_NOT_FOUND;
    break;
  case HA_ERR_WRONG_TABLE_DEF:
    textno=ER_WRONG_MRG_TABLE;
    break;
  case HA_ERR_FOUND_DUPP_KEY:
  {
    uint key_nr=get_dup_key(error);
    if ((int) key_nr >= 0)
    {
      /* Write the dupplicated key in the error message */
      char key[MAX_KEY_LENGTH];
      String str(key,sizeof(key));
      key_unpack(&str,table,(uint) key_nr);
      uint max_length=MYSQL_ERRMSG_SIZE-(uint) strlen(ER(ER_DUP_ENTRY));
      if (str.length() >= max_length)
      {
	str.length(max_length-4);
	str.append("...");
      }
      my_error(ER_DUP_ENTRY,MYF(0),str.c_ptr(),key_nr+1);
      DBUG_VOID_RETURN;
    }
    textno=ER_DUP_KEY;
    break;
  }
  case HA_ERR_FOUND_DUPP_UNIQUE:
    textno=ER_DUP_UNIQUE;
    break;
  case HA_ERR_RECORD_CHANGED:
    textno=ER_CHECKREAD;
    break;
  case HA_ERR_CRASHED:
    textno=ER_NOT_KEYFILE;
    break;
  case HA_ERR_CRASHED_ON_USAGE:
    textno=ER_CRASHED_ON_USAGE;
    break;
  case HA_ERR_CRASHED_ON_REPAIR:
    textno=ER_CRASHED_ON_REPAIR;
    break;
  case HA_ERR_OUT_OF_MEM:
    my_error(ER_OUT_OF_RESOURCES,errflag);
    DBUG_VOID_RETURN;
  case HA_ERR_WRONG_COMMAND:
    textno=ER_ILLEGAL_HA;
    break;
  case HA_ERR_OLD_FILE:
    textno=ER_OLD_KEYFILE;
    break;
  case HA_ERR_UNSUPPORTED:
    textno=ER_UNSUPPORTED_EXTENSION;
    break;
  case HA_ERR_RECORD_FILE_FULL:
    textno=ER_RECORD_FILE_FULL;
    break;
  default:
    {
      my_error(ER_GET_ERRNO,errflag,error);
      DBUG_VOID_RETURN;
    }
  }
  my_error(textno,errflag,table->table_name,error);
  DBUG_VOID_RETURN;
}

	/* Return key if error because of duplicated keys */

uint handler::get_dup_key(int error)
{
  DBUG_ENTER("get_dup_key");
  table->file->errkey  = (uint) -1;
  if (error == HA_ERR_FOUND_DUPP_KEY || error == HA_ERR_FOUND_DUPP_UNIQUE)
    info(HA_STATUS_ERRKEY | HA_STATUS_NO_LOCK);
  DBUG_RETURN(table->file->errkey);
}

int handler::delete_table(const char *name)
{
  int error=0;
  for (const char **ext=bas_ext(); *ext ; ext++)
  {
    if (delete_file(name,*ext,2))
    {
      if ((error=errno) != ENOENT)
	break;
    }
  }
  return error;
}


int handler::rename_table(const char * from, const char * to)
{
  DBUG_ENTER("handler::rename_table");
  for (const char **ext=bas_ext(); *ext ; ext++)
  {
    if (rename_file_ext(from,to,*ext))
      DBUG_RETURN(my_errno);
  }
  DBUG_RETURN(0);
}

int ha_commit_rename(THD *thd)
{
  int error=0;
#ifdef HAVE_GEMINI_DB
    /* Gemini needs to commit the rename; otherwise a rollback will change
    ** the table names back internally but the physical files will still
    ** have the new names.
    */
    if (ha_commit_stmt(thd))
      error= -1;
    if (ha_commit(thd))
      error= -1;
#endif
    return error;
}

int handler::index_next_same(byte *buf, const byte *key, uint keylen)
{
  int error;
  if (!(error=index_next(buf)))
  {
    if (key_cmp(table, key, active_index, keylen))
    {
      table->status=STATUS_NOT_FOUND;
      error=HA_ERR_END_OF_FILE;
    }
  }
  return error;
}


/*
  The following is only needed if we would like to use the database
  for internal temporary tables
*/

int handler::delete_all_rows()
{
  return (my_errno=HA_ERR_WRONG_COMMAND);
}

/****************************************************************************
** Some general functions that isn't in the handler class
****************************************************************************/

	/* Initiates table-file and calls apropriate database-creator */
	/* Returns 1 if something got wrong */

int ha_create_table(const char *name, HA_CREATE_INFO *create_info,
		    bool update_create_info)

{
  int error;
  TABLE table;
  DBUG_ENTER("ha_create_table");

  if (openfrm(name,"",0,(uint) READ_ALL, 0, &table))
    DBUG_RETURN(1);
  if (update_create_info)
  {
    update_create_info_from_table(create_info, &table);
    if (table.file->option_flag() & HA_DROP_BEFORE_CREATE)
      table.file->delete_table(name);		// Needed for BDB tables
  }
  error=table.file->create(name,&table,create_info);
  VOID(closefrm(&table));
  if (error)
    my_error(ER_CANT_CREATE_TABLE,MYF(ME_BELL+ME_WAITTANG),name,my_errno);
  DBUG_RETURN(error != 0);
}

	/* Use key cacheing on all databases */

void ha_key_cache(void)
{
  if (keybuff_size)
    (void) init_key_cache(keybuff_size,0);
} /* ha_key_cache */


static int NEAR_F delete_file(const char *name,const char *ext,int extflag)
{
  char buff[FN_REFLEN];
  VOID(fn_format(buff,name,"",ext,extflag | 4));
  return(my_delete(buff,MYF(MY_WME)));
}