Commit 4389be75 authored by unknown's avatar unknown
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Fix for bug #6462 "Same request on same data returns different 

results." a.k.a. "Proper cleanup of subqueries is missing for SET and DO
statements". (Version #2 with after-review fixes).

To perform proper cleanup for statements that can contain subqueries 
but don't have main select we must call free_undelaid_joins().


mysql-test/r/subselect.result:
  Added test for bug #6462 "Same request on same data returns different
  results." a.k.a. "Proper cleanup of subqueries is missing for SET and DO
  statements".
mysql-test/t/subselect.test:
  Added test for bug #6462 "Same request on same data returns different
  results." a.k.a. "Proper cleanup of subqueries is missing for SET and DO
  statements".
sql/set_var.cc:
  Added missing cleanup of joins used in subqueries to SET statement.
sql/sql_do.cc:
  Added missing cleanup of joins used in subqueries to DO statement.
parent fe37a147

mysql-test/r/subselect.result

+15 −0
Original line number Diff line number Diff line
@@ -1990,3 +1990,18 @@ ac 
700

NULL

drop tables t1,t2;

create table t1 (a int not null, b int not null, c int, primary key (a,b));

insert into t1 values (1,1,1), (2,2,2), (3,3,3);

set @b:= 0;

explain select sum(a) from t1 where b > @b;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	index	NULL	PRIMARY	8	NULL	3	Using where; Using index

set @a:= (select sum(a) from t1 where b > @b);

explain select a from t1 where c=2;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using where

do @a:= (select sum(a) from t1 where b > @b);

explain select a from t1 where c=2;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using where

drop table t1;

mysql-test/t/subselect.test

+19 −0
Original line number Diff line number Diff line
@@ -1282,3 +1282,22 @@ INSERT INTO `t2` VALUES (6,5,12,7,'a'),(12,0,0,7,'a'),(12,1,0,7,'a'),(12,5,5,7,' 
SELECT b.sc FROM (SELECT (SELECT a.access FROM t1 a WHERE a.map = op.map AND a.slave = op.pid AND a.master = 1) ac FROM t2 op WHERE op.id = 12 AND op.map = 0) b;

SELECT b.ac FROM (SELECT (SELECT a.access FROM t1 a WHERE a.map = op.map AND a.slave = op.pid AND a.master = 1) ac FROM t2 op WHERE op.id = 12 AND op.map = 0) b;

drop tables t1,t2;



#

# Test for bug #6462. "Same request on same data returns different

# results." a.k.a. "Proper cleanup of subqueries is missing for 

# SET and DO statements".

#

create table t1 (a int not null, b int not null, c int, primary key (a,b));

insert into t1 values (1,1,1), (2,2,2), (3,3,3);

set @b:= 0;

# Let us check that subquery will use covering index

explain select sum(a) from t1 where b > @b;

# This should not crash -debug server due to failing assertion

set @a:= (select sum(a) from t1 where b > @b);

# And this should not falsely report index usage

explain select a from t1 where c=2;

# Same for DO statement

do @a:= (select sum(a) from t1 where b > @b);

explain select a from t1 where c=2;

drop table t1;

sql/set_var.cc

+11 −6
Original line number Diff line number Diff line
@@ -2703,13 +2703,18 @@ int sql_set_variables(THD *thd, List<set_var_base> *var_list) 
  while ((var=it++))

  {

    if ((error=var->check(thd)))

      DBUG_RETURN(error);

      goto err;

  }

  if (thd->net.report_error)

    DBUG_RETURN(1);

  if (!thd->net.report_error)

  {

    it.rewind();

    while ((var= it++))

      error|= var->update(thd);         // Returns 0, -1 or 1

  }

  else

    error= 1;

err:

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

  DBUG_RETURN(error);

}

sql/sql_do.cc

+1 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ int mysql_do(THD *thd, List<Item> &values) 
    DBUG_RETURN(-1);

  while ((value = li++))

    value->val_int();

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

  thd->clear_error(); // DO always is OK

  send_ok(thd);

  DBUG_RETURN(0);