~drizzle-trunk/drizzle/development

/* 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; 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 */

/*

  Delete of records and truncate of tables.

  Multi-table deletes were introduced by Monty and Sinisa

*/

#include "mysql_priv.h"

#include "sql_select.h"

/**

  Implement DELETE SQL word.

  @note Like implementations of other DDL/DML in MySQL, this function

  relies on the caller to close the thread tables. This is done in the

  end of dispatch_command().

*/

bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,

                  SQL_LIST *order, ha_rows limit, uint64_t options,

                  bool reset_auto_increment)

{

  bool          will_batch;

  int		error, loc_error;

  TABLE		*table;

  SQL_SELECT	*select=0;

  READ_RECORD	info;

  bool          using_limit=limit != HA_POS_ERROR;

  bool		transactional_table, safe_update, const_cond;

  bool          const_cond_result;

  ha_rows	deleted= 0;

  uint usable_index= MAX_KEY;

  SELECT_LEX   *select_lex= &thd->lex->select_lex;

  THD::killed_state killed_status= THD::NOT_KILLED;

  if (open_and_lock_tables(thd, table_list))

    return(true);

  /* TODO look at this error */

  if (!(table= table_list->table))

  {

    my_error(ER_VIEW_DELETE_MERGE_VIEW, MYF(0), "", "");

    return(true);

  }

  thd_proc_info(thd, "init");

  table->map=1;

  if (mysql_prepare_delete(thd, table_list, &conds))

    goto err;

  /* check ORDER BY even if it can be ignored */

  if (order && order->elements)

  {

    TABLE_LIST   tables;

    List<Item>   fields;

    List<Item>   all_fields;

    bzero((char*) &tables,sizeof(tables));

    tables.table = table;

    tables.alias = table_list->alias;

      if (select_lex->setup_ref_array(thd, order->elements) ||

	  setup_order(thd, select_lex->ref_pointer_array, &tables,

                    fields, all_fields, (ORDER*) order->first))

    {

      delete select;

      free_underlaid_joins(thd, &thd->lex->select_lex);

      goto err;

    }

  }

  const_cond= (!conds || conds->const_item());

  safe_update=test(thd->options & OPTION_SAFE_UPDATES);

  if (safe_update && const_cond)

  {

    my_message(ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE,

               ER(ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE), MYF(0));

    goto err;

  }

  select_lex->no_error= thd->lex->ignore;

  const_cond_result= const_cond && (!conds || conds->val_int());

  if (thd->is_error())

  {

    /* Error evaluating val_int(). */

    return(true);

  }

  /*

    Test if the user wants to delete all rows and deletion doesn't have

    any side-effects (because of triggers), so we can use optimized

    handler::delete_all_rows() method.

    We implement fast TRUNCATE for InnoDB even if triggers are

    present.  TRUNCATE ignores triggers.

    We can use delete_all_rows() if and only if:

    - We allow new functions (not using option --skip-new), and are

      not in safe mode (not using option --safe-mode)

    - There is no limit clause

    - The condition is constant

    - If there is a condition, then it it produces a non-zero value

    - If the current command is DELETE FROM with no where clause

      (i.e., not TRUNCATE) then:

      - We should not be binlogging this statement row-based, and

      - there should be no delete triggers associated with the table.

  */

  if (!using_limit && const_cond_result &&

      !(specialflag & (SPECIAL_NO_NEW_FUNC | SPECIAL_SAFE_MODE)) &&

      (thd->lex->sql_command == SQLCOM_TRUNCATE ||

       (!thd->current_stmt_binlog_row_based)))

  {

    /* Update the table->file->stats.records number */

    table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);

    ha_rows const maybe_deleted= table->file->stats.records;

    if (!(error=table->file->ha_delete_all_rows()))

    {

      error= -1;				// ok

      deleted= maybe_deleted;

      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 */

  }

  if (conds)

  {

    Item::cond_result result;

    conds= remove_eq_conds(thd, conds, &result);

    if (result == Item::COND_FALSE)             // Impossible where

      limit= 0;

  }

  /* Update the table->file->stats.records number */

  table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);

  table->covering_keys.clear_all();

  table->quick_keys.clear_all();		// Can't use 'only index'

  select=make_select(table, 0, 0, conds, 0, &error);

  if (error)

    goto err;

  if ((select && select->check_quick(thd, safe_update, limit)) || !limit)

  {

    delete select;

    free_underlaid_joins(thd, select_lex);

    thd->row_count_func= 0;

    MYSQL_DELETE_END();

    my_ok(thd, (ha_rows) thd->row_count_func);

    /*

      We don't need to call reset_auto_increment in this case, because

      mysql_truncate always gives a NULL conds argument, hence we never

      get here.

    */

    return(0);				// Nothing to delete

  }

  /* If running in safe sql mode, don't allow updates without keys */

  if (table->quick_keys.is_clear_all())

  {

    thd->server_status|=SERVER_QUERY_NO_INDEX_USED;

    if (safe_update && !using_limit)

    {

      delete select;

      free_underlaid_joins(thd, select_lex);

      my_message(ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE,

                 ER(ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE), MYF(0));

      goto err;

    }

  }

  if (options & OPTION_QUICK)

    (void) table->file->extra(HA_EXTRA_QUICK);

  if (order && order->elements)

  {

    uint         length= 0;

    SORT_FIELD  *sortorder;

    ha_rows examined_rows;

    if ((!select || table->quick_keys.is_clear_all()) && limit != HA_POS_ERROR)

      usable_index= get_index_for_order(table, (ORDER*)(order->first), limit);

    if (usable_index == MAX_KEY)

    {

      table->sort.io_cache= (IO_CACHE *) my_malloc(sizeof(IO_CACHE),

                                                   MYF(MY_FAE | MY_ZEROFILL));

      if (!(sortorder= make_unireg_sortorder((ORDER*) order->first,

                                             &length, NULL)) ||

	  (table->sort.found_records = filesort(thd, table, sortorder, length,

                                                select, HA_POS_ERROR, 1,

                                                &examined_rows))

	  == HA_POS_ERROR)

      {

        delete select;

        free_underlaid_joins(thd, &thd->lex->select_lex);

        goto err;

      }

      /*

        Filesort has already found and selected the rows we want to delete,

        so we don't need the where clause

      */

      delete select;

      free_underlaid_joins(thd, select_lex);

      select= 0;

    }

  }

  /* If quick select is used, initialize it before retrieving rows. */

  if (select && select->quick && select->quick->reset())

  {

    delete select;

    free_underlaid_joins(thd, select_lex);

    goto err;

  }

  if (usable_index==MAX_KEY)

    init_read_record(&info,thd,table,select,1,1);

  else

    init_read_record_idx(&info, thd, table, 1, usable_index);

  thd_proc_info(thd, "updating");

  will_batch= !table->file->start_bulk_delete();

  table->mark_columns_needed_for_delete();

  while (!(error=info.read_record(&info)) && !thd->killed &&

	 ! thd->is_error())

  {

    // thd->is_error() is tested to disallow delete row on error

    if (!(select && select->skip_record())&& ! thd->is_error() )

    {

      if (!(error= table->file->ha_delete_row(table->record[0])))

      {

	deleted++;

	if (!--limit && using_limit)

	{

	  error= -1;

	  break;

	}

      }

      else

      {

	table->file->print_error(error,MYF(0));

	/*

	  In < 4.0.14 we set the error number to 0 here, but that

	  was not sensible, because then MySQL would not roll back the

	  failed DELETE, and also wrote it to the binlog. For MyISAM

	  tables a DELETE probably never should fail (?), but for

	  InnoDB it can fail in a FOREIGN KEY error or an

	  out-of-tablespace error.

	*/

 	error= 1;

	break;

      }

    }

    else

      table->file->unlock_row();  // Row failed selection, release lock on it

  }

  killed_status= thd->killed;

  if (killed_status != THD::NOT_KILLED || thd->is_error())

    error= 1;					// Aborted

  if (will_batch && (loc_error= table->file->end_bulk_delete()))

  {

    if (error != 1)

      table->file->print_error(loc_error,MYF(0));

    error=1;

  }

  thd_proc_info(thd, "end");

  end_read_record(&info);

  if (options & OPTION_QUICK)

    (void) table->file->extra(HA_EXTRA_NORMAL);

  if (reset_auto_increment && (error < 0))

  {

    /*

      We're really doing a truncate and need to reset the table's

      auto-increment counter.

    */

    int error2= table->file->ha_reset_auto_increment(0);

    if (error2 && (error2 != HA_ERR_WRONG_COMMAND))

    {

      table->file->print_error(error2, MYF(0));

      error= 1;

    }

  }

cleanup:

  delete select;

  transactional_table= table->file->has_transactions();

  if (!transactional_table && deleted > 0)

    thd->transaction.stmt.modified_non_trans_table= true;

  /* See similar binlogging code in sql_update.cc, for comments */

  if ((error < 0) || thd->transaction.stmt.modified_non_trans_table)

  {

    if (mysql_bin_log.is_open())

    {

      if (error < 0)

        thd->clear_error();

      /*

        [binlog]: If 'handler::delete_all_rows()' was called and the

        storage engine does not inject the rows itself, we replicate

        statement-based; otherwise, 'ha_delete_row()' was used to

        delete specific rows which we might log row-based.

      */

      int log_result= thd->binlog_query(THD::ROW_QUERY_TYPE,

                                        thd->query, thd->query_length,

                                        transactional_table, false, killed_status);

      if (log_result && transactional_table)

      {

	error=1;

      }

    }

    if (thd->transaction.stmt.modified_non_trans_table)

      thd->transaction.all.modified_non_trans_table= true;

  }

  assert(transactional_table || !deleted || thd->transaction.stmt.modified_non_trans_table);

  free_underlaid_joins(thd, select_lex);

  MYSQL_DELETE_END();

  if (error < 0 || (thd->lex->ignore && !thd->is_fatal_error))

  {

    thd->row_count_func= deleted;

    my_ok(thd, (ha_rows) thd->row_count_func);

  }

  return(error >= 0 || thd->is_error());

err:

  MYSQL_DELETE_END();

  return(true);

}

/*

  Prepare items in DELETE statement

  SYNOPSIS

    mysql_prepare_delete()

    thd			- thread handler

    table_list		- global/local table list

    conds		- conditions

  RETURN VALUE

    false OK

    true  error

*/

int mysql_prepare_delete(THD *thd, TABLE_LIST *table_list, Item **conds)

{

  SELECT_LEX *select_lex= &thd->lex->select_lex;

  List<Item> all_fields;

  /*

    Statement-based replication of DELETE ... LIMIT is not safe as order of

    rows is not defined, so in mixed mode we go to row-based.

    Note that we may consider a statement as safe if ORDER BY primary_key

    is present. However it may confuse users to see very similiar statements

    replicated differently.

  */

  if (thd->lex->current_select->select_limit)

  {

    thd->lex->set_stmt_unsafe();

    thd->set_current_stmt_binlog_row_based_if_mixed();

  }

  thd->lex->allow_sum_func= 0;

  if (setup_tables_and_check_access(thd, &thd->lex->select_lex.context,

                                    &thd->lex->select_lex.top_join_list,

                                    table_list, 

                                    &select_lex->leaf_tables, false) ||

      setup_conds(thd, table_list, select_lex->leaf_tables, conds))

    return(true);

  {

    TABLE_LIST *duplicate;

    if ((duplicate= unique_table(thd, table_list, table_list->next_global, 0)))

    {

      update_non_unique_table_error(table_list, "DELETE", duplicate);

      return(true);

    }

  }

  if (select_lex->inner_refs_list.elements &&

    fix_inner_refs(thd, all_fields, select_lex, select_lex->ref_pointer_array))

    return(-1);

  return(false);

}

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

  Delete multiple tables from join 

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

#define MEM_STRIP_BUF_SIZE current_thd->variables.sortbuff_size

extern "C" int refpos_order_cmp(void* arg, const void *a,const void *b)

{

  handler *file= (handler*)arg;

  return file->cmp_ref((const uchar*)a, (const uchar*)b);

}

/*

  make delete specific preparation and checks after opening tables

  SYNOPSIS

    mysql_multi_delete_prepare()

    thd         thread handler

  RETURN

    false OK

    true  Error

*/

int mysql_multi_delete_prepare(THD *thd)

{

  LEX *lex= thd->lex;

  TABLE_LIST *aux_tables= (TABLE_LIST *)lex->auxiliary_table_list.first;

  TABLE_LIST *target_tbl;

  /*

    setup_tables() need for VIEWs. JOIN::prepare() will not do it second

    time.

    lex->query_tables also point on local list of DELETE SELECT_LEX

  */

  if (setup_tables_and_check_access(thd, &thd->lex->select_lex.context,

                                    &thd->lex->select_lex.top_join_list,

                                    lex->query_tables,

                                    &lex->select_lex.leaf_tables, false))

    return(true);

  /*

    Multi-delete can't be constructed over-union => we always have

    single SELECT on top and have to check underlying SELECTs of it

  */

  lex->select_lex.exclude_from_table_unique_test= true;

  /* Fix tables-to-be-deleted-from list to point at opened tables */

  for (target_tbl= (TABLE_LIST*) aux_tables;

       target_tbl;

       target_tbl= target_tbl->next_local)

  {

    if (!(target_tbl->table= target_tbl->correspondent_table->table))

    {

      assert(target_tbl->correspondent_table->merge_underlying_list &&

                  target_tbl->correspondent_table->merge_underlying_list->

                  next_local);

      my_error(ER_VIEW_DELETE_MERGE_VIEW, MYF(0), "", "");

      return(true);

    }

    /*

      Check that table from which we delete is not used somewhere

      inside subqueries/view.

    */

    {

      TABLE_LIST *duplicate;

      if ((duplicate= unique_table(thd, target_tbl->correspondent_table,

                                   lex->query_tables, 0)))

      {

        update_non_unique_table_error(target_tbl->correspondent_table,

                                      "DELETE", duplicate);

        return(true);

      }

    }

  }

  return(false);

}

multi_delete::multi_delete(TABLE_LIST *dt, uint num_of_tables_arg)

  : delete_tables(dt), deleted(0), found(0),

    num_of_tables(num_of_tables_arg), error(0),

    do_delete(0), transactional_tables(0), normal_tables(0), error_handled(0)

{

  tempfiles= (Unique **) sql_calloc(sizeof(Unique *) * num_of_tables);

}

int

multi_delete::prepare(List<Item> &values __attribute__((unused)),

                      SELECT_LEX_UNIT *u)

{

  unit= u;

  do_delete= 1;

  thd_proc_info(thd, "deleting from main table");

  return(0);

}

bool

multi_delete::initialize_tables(JOIN *join)

{

  TABLE_LIST *walk;

  Unique **tempfiles_ptr;

  if ((thd->options & OPTION_SAFE_UPDATES) && error_if_full_join(join))

    return(1);

  table_map tables_to_delete_from=0;

  for (walk= delete_tables; walk; walk= walk->next_local)

    tables_to_delete_from|= walk->table->map;

  walk= delete_tables;

  delete_while_scanning= 1;

  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_local;

      /* Don't use KEYREAD optimization on this table */

      tbl->no_keyread=1;

      /* Don't use record cache */

      tbl->no_cache= 1;

      tbl->covering_keys.clear_all();

      if (tbl->file->has_transactions())

	transactional_tables= 1;

      else

	normal_tables= 1;

      tbl->prepare_for_position();

      tbl->mark_columns_needed_for_delete();

    }

    else if ((tab->type != JT_SYSTEM && tab->type != JT_CONST) &&

             walk == delete_tables)

    {

      /*

        We are not deleting from the table we are scanning. In this

        case send_data() shouldn't delete any rows a we may touch

        the rows in the deleted table many times

      */

      delete_while_scanning= 0;

    }

  }

  walk= delete_tables;

  tempfiles_ptr= tempfiles;

  if (delete_while_scanning)

  {

    table_being_deleted= delete_tables;

    walk= walk->next_local;

  }

  for (;walk ;walk= walk->next_local)

  {

    TABLE *table=walk->table;

    *tempfiles_ptr++= new Unique (refpos_order_cmp,

				  (void *) table->file,

				  table->file->ref_length,

				  MEM_STRIP_BUF_SIZE);

  }

  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_local)

  {

    TABLE *table= table_being_deleted->table;

    table->no_keyread=0;

  }

  for (uint counter= 0; counter < num_of_tables; counter++)

  {

    if (tempfiles[counter])

      delete tempfiles[counter];

  }

}

bool multi_delete::send_data(List<Item> &values __attribute__((unused)))

{

  int secure_counter= delete_while_scanning ? -1 : 0;

  TABLE_LIST *del_table;

  for (del_table= delete_tables;

       del_table;

       del_table= del_table->next_local, secure_counter++)

  {

    TABLE *table= del_table->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]);

    found++;

    if (secure_counter < 0)

    {

      /* We are scanning the current table */

      assert(del_table == table_being_deleted);

      table->status|= STATUS_DELETED;

      if (!(error=table->file->ha_delete_row(table->record[0])))

      {

        deleted++;

        if (!table->file->has_transactions())

          thd->transaction.stmt.modified_non_trans_table= true;

      }

      else

      {

        table->file->print_error(error,MYF(0));

        return(1);

      }

    }

    else

    {

      error=tempfiles[secure_counter]->unique_add((char*) table->file->ref);

      if (error)

      {

	error= 1;                               // Fatal error

	return(1);

      }

    }

  }

  return(0);

}

void multi_delete::send_error(uint errcode,const char *err)

{

  /* First send error what ever it is ... */

  my_message(errcode, err, MYF(0));

  return;

}

void multi_delete::abort()

{

  /* the error was handled or nothing deleted and no side effects return */

  if (error_handled ||

      (!thd->transaction.stmt.modified_non_trans_table && !deleted))

    return;

  /*

    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 (do_delete && normal_tables &&

      (table_being_deleted != delete_tables ||

       !table_being_deleted->table->file->has_transactions()))

  {

    /*

      We have to execute the recorded do_deletes() and write info into the

      error log

    */

    error= 1;

    send_eof();

    assert(error_handled);

    return;

  }

  if (thd->transaction.stmt.modified_non_trans_table)

  {

    /* 

       there is only side effects; to binlog with the error

    */

    if (mysql_bin_log.is_open())

    {

      thd->binlog_query(THD::ROW_QUERY_TYPE,

                        thd->query, thd->query_length,

                        transactional_tables, false);

    }

    thd->transaction.all.modified_non_trans_table= true;

  }

  return;

}

/*

  Do delete from other tables.

  Returns values:

	0 ok

	1 error

*/

int multi_delete::do_deletes()

{

  int local_error= 0, counter= 0, tmp_error;

  bool will_batch;

  assert(do_delete);

  do_delete= 0;                                 // Mark called

  if (!found)

    return(0);

  table_being_deleted= (delete_while_scanning ? delete_tables->next_local :

                        delete_tables);

  for (; table_being_deleted;

       table_being_deleted= table_being_deleted->next_local, counter++)

  { 

    ha_rows last_deleted= deleted;

    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;

    will_batch= !table->file->start_bulk_delete();

    while (!(local_error=info.read_record(&info)) && !thd->killed)

    {

      if ((local_error=table->file->ha_delete_row(table->record[0])))

      {

	table->file->print_error(local_error,MYF(0));

	break;

      }

      deleted++;

    }

    if (will_batch && (tmp_error= table->file->end_bulk_delete()))