database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-08-08 11:22:35 +03:00
Code Activity

Problem was that for cases like:

Browse Source 
SELECT ... WHERE XX IN (SELECT YY)
this was transformed to something like:
SELECT ... WHERE IF_EXISTS(SELECT ... HAVING XX=YY)

The bug was that for normal execution XX was fixed in the original outer SELECT context while in PS it was fixed in the sub query context and this confused the optimizer.

Fixed by ensuring that XX is always fixed in the outer context.
This commit is contained in:
Monty
2015-06-25 23:26:29 +03:00
parent 2e941fe9fc
commit 8c815751c9
6 changed files with 102 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
mysql-test/r/subselect_mat.result
View File

@@ -2145,6 +2145,33 @@ drop database mysqltest1;
drop database mysqltest2;
drop database mysqltest3;
drop database mysqltest4;
#
# MDEV-7810 Wrong result on execution of a query as a PS
# (both 1st and further executions)
CREATE TABLE t1 (a INT NOT NULL) ENGINE=MyISAM;
INSERT INTO t1 VALUES (0),(8);
SELECT DISTINCT t9.* FROM t1 AS t9, t1 AS t2;
a
0
8
SELECT MIN(t3.a) FROM ( t1 AS t3 INNER JOIN t1 AS t4 ON (t3.a = t4.a));
MIN(t3.a)
0
SELECT a FROM ( SELECT DISTINCT t9.* FROM t1 AS t9, t1 AS t2 ) AS sq
WHERE a IN ( SELECT MIN(t3.a) FROM ( t1 AS t3 INNER JOIN t1 AS t4 ON (t3.a = t4.a) ) );
a
0
PREPARE stmt FROM "
SELECT a FROM ( SELECT DISTINCT t9.* FROM t1 AS t9, t1 AS t2 ) AS sq
WHERE a IN ( SELECT MIN(t3.a) FROM ( t1 AS t3 INNER JOIN t1 AS t4 ON (t3.a = t4.a) ) )
";
execute stmt;
a
0
execute stmt;
a
0
drop table t1;
# End of 5.5 tests
set @subselect_mat_test_optimizer_switch_value=null;
set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';

27
mysql-test/r/subselect_sj_mat.result
View File

@@ -2185,4 +2185,31 @@ drop database mysqltest1;
drop database mysqltest2;
drop database mysqltest3;
drop database mysqltest4;
#
# MDEV-7810 Wrong result on execution of a query as a PS
# (both 1st and further executions)
CREATE TABLE t1 (a INT NOT NULL) ENGINE=MyISAM;
INSERT INTO t1 VALUES (0),(8);
SELECT DISTINCT t9.* FROM t1 AS t9, t1 AS t2;
a
0
8
SELECT MIN(t3.a) FROM ( t1 AS t3 INNER JOIN t1 AS t4 ON (t3.a = t4.a));
MIN(t3.a)
0
SELECT a FROM ( SELECT DISTINCT t9.* FROM t1 AS t9, t1 AS t2 ) AS sq
WHERE a IN ( SELECT MIN(t3.a) FROM ( t1 AS t3 INNER JOIN t1 AS t4 ON (t3.a = t4.a) ) );
a
0
PREPARE stmt FROM "
SELECT a FROM ( SELECT DISTINCT t9.* FROM t1 AS t9, t1 AS t2 ) AS sq
WHERE a IN ( SELECT MIN(t3.a) FROM ( t1 AS t3 INNER JOIN t1 AS t4 ON (t3.a = t4.a) ) )
";
execute stmt;
a
0
execute stmt;
a
0
drop table t1;
# End of 5.5 tests

21
mysql-test/t/subselect_sj_mat.test
View File

@@ -1841,5 +1841,24 @@ drop database mysqltest2;
drop database mysqltest3;
drop database mysqltest4;
--echo # End of 5.5 tests
--echo #
--echo # MDEV-7810 Wrong result on execution of a query as a PS
--echo # (both 1st and further executions)
CREATE TABLE t1 (a INT NOT NULL) ENGINE=MyISAM;
INSERT INTO t1 VALUES (0),(8);
SELECT DISTINCT t9.* FROM t1 AS t9, t1 AS t2;
SELECT MIN(t3.a) FROM ( t1 AS t3 INNER JOIN t1 AS t4 ON (t3.a = t4.a));
SELECT a FROM ( SELECT DISTINCT t9.* FROM t1 AS t9, t1 AS t2 ) AS sq
WHERE a IN ( SELECT MIN(t3.a) FROM ( t1 AS t3 INNER JOIN t1 AS t4 ON (t3.a = t4.a) ) );
PREPARE stmt FROM "
SELECT a FROM ( SELECT DISTINCT t9.* FROM t1 AS t9, t1 AS t2 ) AS sq
WHERE a IN ( SELECT MIN(t3.a) FROM ( t1 AS t3 INNER JOIN t1 AS t4 ON (t3.a = t4.a) ) )
";
execute stmt;
execute stmt;
drop table t1;
--echo # End of 5.5 tests

21
sql/item_subselect.cc
View File

@@ -1999,12 +1999,31 @@ Item_in_subselect::create_single_in_to_exists_cond(JOIN * join,
during JOIN::optimize: this->tmp_having= this->having; this->having= 0;
*/
Item* join_having= join->having ? join->having : join->tmp_having;
DBUG_ENTER("Item_in_subselect::create_single_in_to_exists_cond");
*where_item= NULL;
*having_item= NULL;
/*
For PS we have to do fix_fields(expr) here to ensure that it's
evaluated in the outer context. If not, then fix_having() will do
a fix_fields(expr) in the inner context and mark expr as
'depended', which will cause update_ref_and_keys() to find wrong
keys.
When not running PS, fix_fields(expr) as already been done earlier and
the following test does nothing.
*/
if (expr && !expr->fixed)
{
SELECT_LEX *save_current_select= thd->lex->current_select;
thd->lex->current_select= thd->lex->current_select->outer_select();
bool tmp;
tmp= expr->fix_fields(thd, 0);
thd->lex->current_select= save_current_select;
if (tmp)
DBUG_RETURN(true);
}
if (join_having || select_lex->with_sum_func ||
select_lex->group_list.elements)
{

3
sql/sql_base.cc
View File

@@ -6859,6 +6859,7 @@ find_field_in_tables(THD *thd, Item_ident *item,
if (item->cached_table)
{
DBUG_PRINT("info", ("using cached table"));
/*
This shortcut is used by prepared statements. We assume that
TABLE_LIST *first_table is not changed during query execution (which
@@ -6935,8 +6936,6 @@ find_field_in_tables(THD *thd, Item_ident *item,
return found;
}
}
else
item->can_be_depended= TRUE;
if (db && lower_case_table_names)
{

12
sql/sql_select.cc
View File

@@ -4904,6 +4904,8 @@ update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
KEY_FIELD *key_fields, *end, *field;
uint sz;
uint m= max(select_lex->max_equal_elems,1);
DBUG_ENTER("update_ref_and_keys");
DBUG_PRINT("enter", ("normal_tables: %llx", normal_tables));
SELECT_LEX *sel=thd->lex->current_select;
sel->cond_count= 0;
@@ -4950,7 +4952,7 @@ update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
sz= max(sizeof(KEY_FIELD),sizeof(SARGABLE_PARAM))*
((sel->cond_count*2 + sel->between_count)*m+1);
if (!(key_fields=(KEY_FIELD*) thd->alloc(sz)))
return TRUE; /* purecov: inspected */
DBUG_RETURN(TRUE); /* purecov: inspected */
and_level= 0;
field= end= key_fields;
*sargables= (SARGABLE_PARAM *) key_fields +
@@ -4959,7 +4961,7 @@ update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
(*sargables)[0].field= 0;
if (my_init_dynamic_array(keyuse,sizeof(KEYUSE),20,64))
return TRUE;
DBUG_RETURN(TRUE);
if (cond)
{
@@ -5009,16 +5011,16 @@ update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
for ( ; field != end ; field++)
{
if (add_key_part(keyuse,field))
return TRUE;
DBUG_RETURN(TRUE);
}
if (select_lex->ftfunc_list->elements)
{
if (add_ft_keys(keyuse,join_tab,cond,normal_tables))
return TRUE;
DBUG_RETURN(TRUE);
}
return FALSE;
DBUG_RETURN(FALSE);
}