path: root/sql/sql_delete.cc

/* Copyright (C) 2000 MySQL 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 */


/*
  Delete of records and truncate of tables.

  Multi-table deletes were introduced by Monty and Sinisa
*/



#include "mysql_priv.h"
#include "ha_innodb.h"
#include "sql_select.h"

int mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds, ORDER *order,
                 ha_rows limit, ulong options)
{
  int		error;
  TABLE		*table;
  SQL_SELECT	*select=0;
  READ_RECORD	info;
  bool 		using_limit=limit != HA_POS_ERROR;
  bool		transactional_table, log_delayed, safe_update, const_cond; 
  ha_rows	deleted;
  TABLE_LIST    *delete_table_list= (TABLE_LIST*) 
    thd->lex.select_lex.table_list.first;
  DBUG_ENTER("mysql_delete");

  if ((open_and_lock_tables(thd, table_list)))
    DBUG_RETURN(-1);
  fix_tables_pointers(thd->lex.all_selects_list);
  table= table_list->table;
  table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);
  thd->proc_info="init";
  table->map=1;
  if (setup_conds(thd, delete_table_list, &conds) || 
      setup_ftfuncs(&thd->lex.select_lex))
    DBUG_RETURN(-1);
  if (find_real_table_in_list(table_list->next, 
			      table_list->db, table_list->real_name))
  {
    my_error(ER_UPDATE_TABLE_USED, MYF(0), table_list->real_name);
    DBUG_RETURN(-1);
  }

  const_cond= (!conds || conds->const_item());
  safe_update=test(thd->options & OPTION_SAFE_UPDATES);
  if (safe_update && const_cond)
  {
    send_error(thd,ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE);
    DBUG_RETURN(1);
  }

  /* Test if the user wants to delete all rows */
  if (!using_limit && const_cond &&
      !(specialflag & (SPECIAL_NO_NEW_FUNC | SPECIAL_SAFE_MODE)))
  {
    deleted= table->file->records;
    if (!(error=table->file->delete_all_rows()))
    {
      error= -1;				// ok
      goto cleanup;
    }
    if (error != HA_ERR_WRONG_COMMAND)
    {
      table->file->print_error(error,MYF(0));
      error=0;
      goto cleanup;
    }
    /* Handler didn't support fast delete; Delete rows one by one */
  }

  table->used_keys=table->quick_keys=0;		// Can't use 'only index'
  select=make_select(table,0,0,conds,&error);
  if (error)
    DBUG_RETURN(-1);
  if ((select && select->check_quick(safe_update, limit)) || !limit)
  {
    delete select;
    free_underlaid_joins(thd, &thd->lex.select_lex);
    send_ok(thd,0L);
    DBUG_RETURN(0);				// Nothing to delete
  }

  /* If running in safe sql mode, don't allow updates without keys */
  if (!table->quick_keys)
  {
    thd->lex.select_lex.options|=QUERY_NO_INDEX_USED;
    if (safe_update && !using_limit)
    {
      delete select;
      free_underlaid_joins(thd, &thd->lex.select_lex);
      send_error(thd,ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE);
      DBUG_RETURN(1);
    }
  }
  if (options & OPTION_QUICK)
    (void) table->file->extra(HA_EXTRA_QUICK);

  if (order)
  {
    uint         length;
    SORT_FIELD  *sortorder;
    TABLE_LIST   tables;
    List<Item>   fields;
    List<Item>   all_fields;
    ha_rows examined_rows;

    bzero((char*) &tables,sizeof(tables));
    tables.table = table;

    table->io_cache = (IO_CACHE *) my_malloc(sizeof(IO_CACHE),
                                             MYF(MY_FAE | MY_ZEROFILL));
    if (setup_order(thd, 0, &tables, fields, all_fields, order) ||
        !(sortorder=make_unireg_sortorder(order, &length)) ||
        (table->found_records = filesort(thd, table, sortorder, length,
                                        (SQL_SELECT *) 0, HA_POS_ERROR,
					 &examined_rows))
        == HA_POS_ERROR)
    {
      delete select;
      free_underlaid_joins(thd, &thd->lex.select_lex);
      DBUG_RETURN(-1);		// This will force out message
    }
  }

  init_read_record(&info,thd,table,select,1,1);
  deleted=0L;
  init_ftfuncs(thd, &thd->lex.select_lex, 1);
  thd->proc_info="updating";
  while (!(error=info.read_record(&info)) && !thd->killed &&
	 !thd->net.report_error)
  {
    // thd->net.report_error is tested to disallow delete row on error
    if (!(select && select->skipp_record())&& !thd->net.report_error )
    {
      if (!(error=table->file->delete_row(table->record[0])))
      {
	deleted++;
	if (!--limit && using_limit)
	{
	  error= -1;
	  break;
	}
      }
      else
      {
	table->file->print_error(error,MYF(0));
	error=0;
	break;
      }
    }
    else
      table->file->unlock_row();  // Row failed selection, release lock on it
  }
  thd->proc_info="end";
  end_read_record(&info);
  free_io_cache(table);				// Will not do any harm
  if (options & OPTION_QUICK)
    (void) table->file->extra(HA_EXTRA_NORMAL);

cleanup:
  transactional_table= table->file->has_transactions();
  log_delayed= (transactional_table || table->tmp_table);
  if (deleted && (error <= 0 || !transactional_table))
  {
    mysql_update_log.write(thd,thd->query, thd->query_length);
    if (mysql_bin_log.is_open())
    {
      Query_log_event qinfo(thd, thd->query, thd->query_length, 
			    log_delayed);
      if (mysql_bin_log.write(&qinfo) && transactional_table)
	error=1;
    }
    if (!log_delayed)
      thd->options|=OPTION_STATUS_NO_TRANS_UPDATE;
  }
  if (transactional_table)
  {
    if (ha_autocommit_or_rollback(thd,error >= 0))
      error=1;
  }

  /*
    Store table for future invalidation  or invalidate it in
    the query cache if something changed
  */
  if (deleted)
  {
    query_cache_invalidate3(thd, table_list, 1);
  }
  if (thd->lock)
  {
    mysql_unlock_tables(thd, thd->lock);
    thd->lock=0;
  }
  delete select;
  free_underlaid_joins(thd, &thd->lex.select_lex);
  if (error >= 0 || thd->net.report_error)
    send_error(thd,thd->killed ? ER_SERVER_SHUTDOWN: 0);
  else
  {
    send_ok(thd,deleted);
    DBUG_PRINT("info",("%d records deleted",deleted));
  }
  DBUG_RETURN(0);
}


/***************************************************************************
  Delete multiple tables from join 
***************************************************************************/

#define MEM_STRIP_BUF_SIZE current_thd->variables.sortbuff_size

extern "C" int refposcmp2(void* arg, const void *a,const void *b)
{
  /* arg is a pointer to file->ref_length */
  return memcmp(a,b, *(int*) arg);
}

multi_delete::multi_delete(THD *thd_arg, TABLE_LIST *dt,
			   uint num_of_tables_arg)
  : delete_tables(dt), thd(thd_arg), deleted(0),
    num_of_tables(num_of_tables_arg), error(0),
    do_delete(0), transactional_tables(0), log_delayed(0), normal_tables(0)
{
  tempfiles = (Unique **) sql_calloc(sizeof(Unique *) * (num_of_tables-1));
}


int
multi_delete::prepare(List<Item> &values, SELECT_LEX_UNIT *u)
{
  DBUG_ENTER("multi_delete::prepare");
  unit= u;
  do_delete= 1;
  thd->proc_info="deleting from main table";
  DBUG_RETURN(0);
}


bool
multi_delete::initialize_tables(JOIN *join)
{
  TABLE_LIST *walk;
  Unique **tempfiles_ptr;
  DBUG_ENTER("initialize_tables");

  if ((thd->options & OPTION_SAFE_UPDATES) && error_if_full_join(join))
    DBUG_RETURN(1);

  table_map tables_to_delete_from=0;
  for (walk= delete_tables ; walk ; walk=walk->next)
    tables_to_delete_from|= walk->table->map;

  walk= delete_tables;
  for (JOIN_TAB *tab=join->join_tab, *end=join->join_tab+join->tables;
       tab < end;
       tab++)
  {
    if (tab->table->map & tables_to_delete_from)
    {
      /* We are going to delete from this table */
      TABLE *tbl=walk->table=tab->table;
      walk=walk->next;
      /* Don't use KEYREAD optimization on this table */
      tbl->no_keyread=1;
      tbl->used_keys= 0;
      if (tbl->file->has_transactions())
	log_delayed= transactional_tables= 1;
      else if (tbl->tmp_table != NO_TMP_TABLE)
	log_delayed= 1;
      else
	normal_tables= 1;
    }
  }
  walk= delete_tables;
  tempfiles_ptr= tempfiles;
  for (walk=walk->next ; walk ; walk=walk->next)
  {
    TABLE *table=walk->table;
    *tempfiles_ptr++= new Unique (refposcmp2,
				  (void *) &table->file->ref_length,
				  table->file->ref_length,
				  MEM_STRIP_BUF_SIZE);
  }
  init_ftfuncs(thd, thd->lex.current_select->select_lex(), 1);
  DBUG_RETURN(thd->is_fatal_error != 0);
}


multi_delete::~multi_delete()
{
  for (table_being_deleted=delete_tables ;
       table_being_deleted ;
       table_being_deleted=table_being_deleted->next)
  {
    TABLE *t=table_being_deleted->table;
    free_io_cache(t);				// Alloced by unique
    t->no_keyread=0;
  }

  for (uint counter= 0; counter < num_of_tables-1; counter++)
  {
    if (tempfiles[counter])
      delete tempfiles[counter];
  }
}


bool multi_delete::send_data(List<Item> &values)
{
  int secure_counter= -1;
  DBUG_ENTER("multi_delete::send_data");

  for (table_being_deleted=delete_tables ;
       table_being_deleted ;
       table_being_deleted=table_being_deleted->next, secure_counter++)
  {
    TABLE *table=table_being_deleted->table;

    /* Check if we are using outer join and we didn't find the row */
    if (table->status & (STATUS_NULL_ROW | STATUS_DELETED))
      continue;

    table->file->position(table->record[0]);

    if (secure_counter < 0)
    {
      /* If this is the table we are scanning */
      table->status|= STATUS_DELETED;
      if (!(error=table->file->delete_row(table->record[0])))
	deleted++;
      else if (!table_being_deleted->next)
      {
	table->file->print_error(error,MYF(0));
	DBUG_RETURN(1);
      }
    }
    else
    {
      error=tempfiles[secure_counter]->unique_add((char*) table->file->ref);
      if (error)
      {
	error=-1;
	DBUG_RETURN(1);
      }
    }
  }
  DBUG_RETURN(0);
}

void multi_delete::send_error(uint errcode,const char *err)
{
  DBUG_ENTER("multi_delete::send_error");

  /* First send error what ever it is ... */
  ::send_error(thd,errcode,err);

  /* If nothing deleted return */
  if (!deleted)
    DBUG_VOID_RETURN;

  /* Something already deleted so we have to invalidate cache */
  query_cache_invalidate3(thd, delete_tables, 1);

  /* Below can happen when thread is killed early ... */
  if (!table_being_deleted)
    table_being_deleted=delete_tables;

  /*
    If rows from the first table only has been deleted and it is
    transactional, just do rollback.
    The same if all tables are transactional, regardless of where we are.
    In all other cases do attempt deletes ...
  */
  if ((table_being_deleted->table->file->has_transactions() &&
       table_being_deleted == delete_tables) || !normal_tables)
    ha_rollback_stmt(thd);
  else if (do_delete)
  {
    VOID(do_deletes(1));
  }
  DBUG_VOID_RETURN;
}


/*
  Do delete from other tables.
  Returns values:
	0 ok
	1 error
*/

int multi_delete::do_deletes(bool from_send_error)
{
  int local_error= 0, counter= 0;
  DBUG_ENTER("do_deletes");

  if (from_send_error)
  {
    /* Found out table number for 'table_being_deleted' */
    for (TABLE_LIST *aux=delete_tables;
	 aux != table_being_deleted;
	 aux=aux->next)
      counter++;
  }
  else
    table_being_deleted = delete_tables;

  do_delete= 0;
  for (table_being_deleted=table_being_deleted->next;
       table_being_deleted ;
       table_being_deleted=table_being_deleted->next, counter++)
  { 
    TABLE *table = table_being_deleted->table;
    if (tempfiles[counter]->get(table))
    {
      local_error=1;
      break;
    }

    READ_RECORD	info;
    init_read_record(&info,thd,table,NULL,0,1);
    /*
      Ignore any rows not found in reference tables as they may already have
      been deleted by foreign key handling
    */
    info.ignore_not_found_rows= 1;
    while (!(local_error=info.read_record(&info)) && !thd->killed)
    {
      if ((local_error=table->file->delete_row(table->record[0])))
      {
	table->file->print_error(local_error,MYF(0));
	break;
      }
      deleted++;
    }
    end_read_record(&info);
    if (local_error == -1)				// End of file
      local_error = 0;
  }
  DBUG_RETURN(local_error);
}


/*
  Send ok to the client

  return:  0 sucess
	   1 error
*/

bool multi_delete::send_eof()
{
  thd->proc_info="deleting from reference tables";

  /* Does deletes for the last n - 1 tables, returns 0 if ok */
  int local_error= do_deletes(0);		// returns 0 if success

  /* reset used flags */
  thd->proc_info="end";


  /*
    Write the SQL statement to the binlog if we deleted
    rows and we succeeded, or also in an error case when there
    was a non-transaction-safe table involved, since
    modifications in it cannot be rolled back.
  */
  if (deleted && (error <= 0 || normal_tables))
  {
    mysql_update_log.write(thd,thd->query,thd->query_length);
    if (mysql_bin_log.is_open())
    {
      Query_log_event qinfo(thd, thd->query, thd->query_length,
			    log_delayed);
      if (mysql_bin_log.write(&qinfo) && !normal_tables)
	local_error=1;  // Log write failed: roll back the SQL statement
    }
    if (!log_delayed)
      thd->options|=OPTION_STATUS_NO_TRANS_UPDATE;
  }
  /* Commit or rollback the current SQL statement */ 
  if (transactional_tables)
    if (ha_autocommit_or_rollback(thd,local_error > 0))
      local_error=1;
  
  if (deleted)
    query_cache_invalidate3(thd, delete_tables, 1);

  if (local_error)
    ::send_error(thd);
  else
    ::send_ok(thd, deleted);
  return 0;
}


/***************************************************************************
  TRUNCATE TABLE
****************************************************************************/

/*
  Optimize delete of all rows by doing a full generate of the table
  This will work even if the .ISM and .ISD tables are destroyed

  dont_send_ok should be set if:
  - We should always wants to generate the table (even if the table type
    normally can't safely do this.
  - We don't want an ok to be sent to the end user.
  - We don't want to log the truncate command
  - If we want to have a name lock on the table on exit without errors.
*/

int mysql_truncate(THD *thd, TABLE_LIST *table_list, bool dont_send_ok)
{
  HA_CREATE_INFO create_info;
  char path[FN_REFLEN];
  TABLE **table_ptr;
  int error;
  DBUG_ENTER("mysql_truncate");

  /* If it is a temporary table, close and regenerate it */
  if (!dont_send_ok && (table_ptr=find_temporary_table(thd,table_list->db,
						       table_list->real_name)))
  {
    TABLE *table= *table_ptr;
    HA_CREATE_INFO create_info;
    table->file->info(HA_STATUS_AUTO | HA_STATUS_NO_LOCK);
    bzero((char*) &create_info,sizeof(create_info));
    create_info.auto_increment_value= table->file->auto_increment_value;
    create_info.table_charset=table->table_charset;

    db_type table_type=table->db_type;
    strmov(path,table->path);
    *table_ptr= table->next;			// Unlink table from list
    close_temporary(table,0);
    *fn_ext(path)=0;				// Remove the .frm extension
    ha_create_table(path, &create_info,1);
    // We don't need to call invalidate() because this table is not in cache
    if ((error= (int) !(open_temporary_table(thd, path, table_list->db,
					     table_list->real_name, 1))))
      (void) rm_temporary_table(table_type, path);
    /*
      If we return here we will not have logged the truncation to the bin log
      and we will not send_ok() to the client.
    */
    goto end; 
  }

  (void) sprintf(path,"%s/%s/%s%s",mysql_data_home,table_list->db,
		 table_list->real_name,reg_ext);
  fn_format(path,path,"","",4);

  if (!dont_send_ok)
  {
    db_type table_type;
    if ((table_type=get_table_type(path)) == DB_TYPE_UNKNOWN)
    {
      my_error(ER_NO_SUCH_TABLE, MYF(0), table_list->db,
	       table_list->real_name);
      DBUG_RETURN(-1);
    }
    if (!ha_supports_generate(table_type))
    {
      /* Probably InnoDB table */
      table_list->lock_type= TL_WRITE;
      DBUG_RETURN(mysql_delete(thd, table_list, (COND*) 0, (ORDER*) 0,
			       HA_POS_ERROR, 0));
    }
    if (lock_and_wait_for_table_name(thd, table_list))
      DBUG_RETURN(-1);
  }

  bzero((char*) &create_info,sizeof(create_info));
  create_info.table_charset=table_list->table->table_charset;

  *fn_ext(path)=0;				// Remove the .frm extension
  error= ha_create_table(path,&create_info,1) ? -1 : 0;
  query_cache_invalidate3(thd, table_list, 0); 

end:
  if (!dont_send_ok)
  {
    if (!error)
    {
      mysql_update_log.write(thd,thd->query,thd->query_length);
      if (mysql_bin_log.is_open())
      {
	Query_log_event qinfo(thd, thd->query, thd->query_length,
			      thd->tmp_table);
	mysql_bin_log.write(&qinfo);
      }
      send_ok(thd);		// This should return record count
    }
    VOID(pthread_mutex_lock(&LOCK_open));
    unlock_table_name(thd, table_list);
    VOID(pthread_mutex_unlock(&LOCK_open));
  }
  else if (error)
  {
    VOID(pthread_mutex_lock(&LOCK_open));
    unlock_table_name(thd, table_list);
    VOID(pthread_mutex_unlock(&LOCK_open));
  }
  DBUG_RETURN(error ? -1 : 0);
}