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Fix for bug #5890 "Triggers fail for DELETE without WHERE".

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If we have DELETE with always true WHERE clause we should not use 
optimized delete_all_rows() method for tables with DELETE triggers,
because in this case we will lose side-effect of deletion.


mysql-test/r/trigger.result:
  Added test for bug #5890 "Triggers fail for DELETE without WHERE".
mysql-test/t/trigger.test:
  Added test for bug #5890 "Triggers fail for DELETE without WHERE".
sql/sql_delete.cc:
  mysql_delete(): 
    We should not use optimized delete_all_rows() method for tables
    with DELETE triggers, because in this case we will lose side-effect
    of deletion.
sql/sql_trigger.h:
  Added new Table_triggers_list::has_delete_triggers() method which
  allows to understand quickly if we have some DELETE triggers in
  our list.
This commit is contained in:
unknown 2004-11-12 17:04:07 +03:00
parent e5fd013fdf
commit bb43e8317f
4 changed files with 42 additions and 2 deletions
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12
mysql-test/r/trigger.result
View File

@ -174,3 +174,15 @@ create trigger tx1 before insert on t1 for each row set new.x1col = 'x';
insert into t1 values ('y');
drop trigger t1.tx1;
drop table t1;
create table t1 (i int) engine=myisam;
insert into t1 values (1), (2);
create trigger trg1 before delete on t1 for each row set @del_before:= @del_before + old.i;
create trigger trg2 after delete on t1 for each row set @del_after:= @del_after + old.i;
set @del_before:=0, @del_after:= 0;
delete from t1;
select @del_before, @del_after;
@del_before @del_after
3 3
drop trigger t1.trg1;
drop trigger t1.trg2;
drop table t1;

17
mysql-test/t/trigger.test
View File

@ -207,3 +207,20 @@ create trigger tx1 before insert on t1 for each row set new.x1col = 'x';
insert into t1 values ('y');
drop trigger t1.tx1;
drop table t1;
#
# Test for bug #5890 "Triggers fail for DELETE without WHERE".
# If we are going to delete all rows in table but DELETE triggers exist
# we should perform row-by-row deletion instead of using optimized
# delete_all_rows() method.
#
create table t1 (i int) engine=myisam;
insert into t1 values (1), (2);
create trigger trg1 before delete on t1 for each row set @del_before:= @del_before + old.i;
create trigger trg2 after delete on t1 for each row set @del_after:= @del_after + old.i;
set @del_before:=0, @del_after:= 0;
delete from t1;
select @del_before, @del_after;
drop trigger t1.trg1;
drop trigger t1.trg2;
drop table t1;

9
sql/sql_delete.cc
View File

@ -62,9 +62,14 @@ int mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds, SQL_LIST *order,
if (thd->lex->duplicates == DUP_IGNORE)
thd->lex->select_lex.no_error= 1;
/* Test if the user wants to delete all rows */
/*
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.
*/
if (!using_limit && const_cond && (!conds || conds->val_int()) &&
!(specialflag & (SPECIAL_NO_NEW_FUNC | SPECIAL_SAFE_MODE)))
!(specialflag & (SPECIAL_NO_NEW_FUNC | SPECIAL_SAFE_MODE)) &&
!(table->triggers && table->triggers->has_delete_triggers()))
{
deleted= table->file->records;
if (!(error=table->file->delete_all_rows()))

6
sql/sql_trigger.h
View File

@ -58,5 +58,11 @@ public:
static bool check_n_load(THD *thd, const char *db, const char *table_name,
TABLE *table);
bool has_delete_triggers()
{
return (bodies[TRG_EVENT_DELETE][TRG_ACTION_BEFORE] ||
bodies[TRG_EVENT_DELETE][TRG_ACTION_AFTER]);
}
friend class Item_trigger_field;
};