| Bug #48060 | Memory leak - Item::val_bool() (item.cc:184) from optimizer_subquery grammar | ||
|---|---|---|---|
| Submitted: | 14 Oct 2009 21:20 | Modified: | 17 Nov 2009 23:17 |
| Reporter: | Patrick Crews | Email Updates: | |
| Status: | Closed | Impact on me: | |
| Category: | MySQL Server: Optimizer | Severity: | S3 (Non-critical) |
| Version: | 5.5, 6.0-codebase | OS: | Any |
| Assigned to: | Tor Didriksen | CPU Architecture: | Any |
| Tags: | memory leak, valgrind | ||
[14 Oct 2009 21:20]
Patrick Crews
[19 Oct 2009 8:49]
Tor Didriksen
The same memory leak can be observed in about a dozen of the tests in the main
test suite.
Here's a simple example to re-create the memory leak
create table t1 (a int, b int);
create table t2 (a int, b int);
create table t3 (a int, b int);
insert into t1 values (0,100),(1,2), (1,3), (2,2), (2,7), (2,-1), (3,10);
insert into t2 values (0,0), (1,1), (2,1), (3,1), (4,1);
insert into t3 values (3,3), (2,2), (1,1);
select a,(select count(distinct t1.b) as sum from t1,t2 where t1.a=t2.a and t2.b > 0 and t1.a <= t3.b group by t1.a order by sum limit 1) from t3;
drop table t1,t2,t3;
The problem seems to be that we call prepare_sum_aggregators()
multiple times. Each invocation of Item_sum::set_aggregator()
will do
aggr= new Aggregator_distinct(this);
and we will leak the previous contents of aggr.
Changing set_aggregator() as shown below, removes all leaks of this sort in the main test suite.
int Item_sum::set_aggregator(Aggregator::Aggregator_type aggregator)
{
DBUG_PRINT("info", ("set_Aggregator this %p old %p", this, aggr));
if (aggr)
{
DBUG_ASSERT(aggregator == aggr->Aggrtype());
return FALSE;
}
switch (aggregator)
{
case Aggregator::DISTINCT_AGGREGATOR:
aggr= new Aggregator_distinct(this);
break;
case Aggregator::SIMPLE_AGGREGATOR:
aggr= new Aggregator_simple(this);
break;
};
DBUG_PRINT("info", ("set_Aggregator this %p new %p", this, aggr));
return aggr ? FALSE : TRUE;
}
[19 Oct 2009 10:30]
Tor Didriksen
Same leak in mysql-next-mr ../sql/mysqld Ver 5.5.0-beta-valgrind-max-debug for pc-linux-gnu on i686 (Source distribution) ==25348== 9,166 (6,822 direct, 2,344 indirect) bytes in 12 blocks are definitely lost in loss record 8 of 9 ==25348== at 0x4006AEE: malloc (vg_replace_malloc.c:207) ==25348== by 0x86CC09C: my_malloc (my_malloc.c:34) ==25348== by 0x86CCA7E: alloc_root (my_alloc.c:158) ==25348== by 0x86CCBCA: multi_alloc_root (my_alloc.c:264) ==25348== by 0x83092F9: create_tmp_table(THD*, TMP_TABLE_PARAM*, List<Item>&, st_order*, bool, bool, unsigned long long, unsigned long long, char*) ( sql_select.cc:9859) ==25348== by 0x81D4DBE: Aggregator_distinct::setup(THD*) (item_sum.cc:762) ==25348== by 0x8322D6C: Item_sum::aggregator_setup(THD*) (item_sum.h:482) ==25348== by 0x82F8D73: _ZL15setup_sum_funcsP3THDPP8Item_sum (sql_select.cc:15437) ==25348== by 0x8321714: JOIN::exec() (sql_select.cc:1979) ==25348== by 0x8231C11: subselect_single_select_engine::exec() (item_subselect.cc:1960) ==25348== by 0x8236B54: Item_subselect::exec() (item_subselect.cc:261) ==25348== by 0x8230118: Item_singlerow_subselect::val_int() (item_subselect.cc:565) ==25348== by 0x81B3639: Item::send(Protocol*, String*) (item.cc:5559) ==25348== by 0x8269245: select_send::send_data(List<Item>&) (sql_class.cc:1689) ==25348== by 0x82F9801: _ZL8end_sendP4JOINP13st_join_tableb (sql_select.cc:12091) ==25348== by 0x83009F2: _ZL20evaluate_join_recordP4JOINP13st_join_tablei (sql_select.cc:11347)
[26 Oct 2009 15:22]
Bugs System
A patch for this bug has been committed. After review, it may be pushed to the relevant source trees for release in the next version. You can access the patch from: http://lists.mysql.com/commits/88188 2921 Tor Didriksen 2009-10-26 Bug#48060 Memory leak - Item::val_bool() (item.cc:184) from optimizer_subquery grammar Item_sum::set_aggregator() may be called multiple times during query preparation. On subsequent calls: verify that the aggregator type is the same, and re-use the existing Aggregator. @ sql/item_sum.cc In Item_sum::set_aggregator(): re-use existing Aggregator if already set. Remove some friend declarations, add some accessor functions. Cleanup some DBUG_ENTER and DBUG_RETURN code. @ sql/item_sum.h Make some member fields private, add accessors instead. Remove some un-necessary friend declarations. Remove some default arguments from constructors. @ sql/opt_sum.cc Use accessor functions in Item_sum. @ sql/sql_select.cc Fix mis-spelled DBUG_ENTER text. Use accessor functions in Item_sum. @ sql/sql_yacc.yy Use explicit true/false rather than default arguments when constructing Item_sum_xxx objects.
[27 Oct 2009 15:38]
Georgi Kodinov
OK to push with one small note (see below) :
@@ -855,23 +859,23 @@ bool Aggregator_distinct::setup(THD *thd
mem_root.
*/
if (field_list.push_back(&field_def))
- return TRUE;
+ DBUG_RETURN(TRUE);
item_sum->null_value= item_sum->maybe_null= 1;
item_sum->quick_group= 0;
DBUG_ASSERT(item_sum->get_arg(0)->fixed);
- arg = item_sum->get_arg(0);
+ Item *arg= item_sum->get_arg(0);
Joro:^^^^^^
Joro:Please remove the local declaration. I don't think it's needed
[28 Oct 2009 7:04]
Bugs System
A patch for this bug has been committed. After review, it may be pushed to the relevant source trees for release in the next version. You can access the patch from: http://lists.mysql.com/commits/88438 2926 Tor Didriksen 2009-10-26 Bug#48060 Memory leak - Item::val_bool() (item.cc:184) from optimizer_subquery grammar Item_sum::set_aggregator() may be called multiple times during query preparation. On subsequent calls: verify that the aggregator type is the same, and re-use the existing Aggregator. @ sql/item_sum.cc In Item_sum::set_aggregator(): re-use existing Aggregator if already set. Remove some friend declarations, add some accessor functions. Cleanup some DBUG_ENTER and DBUG_RETURN code. @ sql/item_sum.h Make some member fields private, add accessors instead. Remove some un-necessary friend declarations. Remove some default arguments from constructors. @ sql/opt_sum.cc Use accessor functions in Item_sum. @ sql/sql_select.cc Fix mis-spelled DBUG_ENTER text. Use accessor functions in Item_sum. @ sql/sql_yacc.yy Use explicit true/false rather than default arguments when constructing Item_sum_xxx objects.
[28 Oct 2009 10:07]
Bugs System
A patch for this bug has been committed. After review, it may be pushed to the relevant source trees for release in the next version. You can access the patch from: http://lists.mysql.com/commits/88465 2927 Tor Didriksen 2009-10-28 Bug#48060 Memory leak - Item::val_bool() (item.cc:184) from optimizer_subquery grammar Item_sum::set_aggregator() may be called multiple times during query preparation. On subsequent calls: verify that the aggregator type is the same, and re-use the existing Aggregator. @ sql/item_sum.cc In Item_sum::set_aggregator(): re-use existing Aggregator if already set. Remove some friend declarations, add some accessor functions. Cleanup some DBUG_ENTER and DBUG_RETURN code. @ sql/item_sum.h Make some member fields private, add accessors instead. Remove some un-necessary friend declarations. Remove some default arguments from constructors. @ sql/opt_sum.cc Use accessor functions in Item_sum. @ sql/sql_select.cc Fix mis-spelled DBUG_ENTER text. Use accessor functions in Item_sum. @ sql/sql_yacc.yy Use explicit true/false rather than default arguments when constructing Item_sum_xxx objects.
[28 Oct 2009 11:16]
Tor Didriksen
pushed to: bzr+ssh://bk-internal.mysql.com/bzrroot/server/mysql-next-mr-bugfixing
[28 Oct 2009 12:49]
Bugs System
A patch for this bug has been committed. After review, it may be pushed to the relevant source trees for release in the next version. You can access the patch from: http://lists.mysql.com/commits/88478 3683 Tor Didriksen 2009-10-28 [merge] Merge fix for Bug#48060 from my:next-mr-bugfixing
[28 Oct 2009 13:30]
Tor Didriksen
pushed to bzr+ssh://bk-internal.mysql.com/bzrroot/server/mysql-6.0-codebase-bugfixing/
[31 Oct 2009 8:19]
Bugs System
Pushed into 6.0.14-alpha (revid:alik@sun.com-20091031081410-qkxmjsdzjmj840aq) (version source revid:tor.didriksen@sun.com-20091028124831-l34xkirry2fu5gtd) (merge vers: 6.0.14-alpha) (pib:13)
[12 Nov 2009 8:17]
Bugs System
Pushed into 5.5.0-beta (revid:alik@sun.com-20091110093229-0bh5hix780cyeicl) (version source revid:mikael@mysql.com-20091102100915-a2nbfxaqprpgptfw) (merge vers: 5.5.0-beta) (pib:13)
[17 Nov 2009 23:17]
Paul DuBois
Noted in 5.5.0, 6.0.14 changelogs. The subquery optimizer had a memory leak.
