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Fixed LP bug #800518.

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The function simple_pred did not take into account that a multiple equality
could include ref items (more exactly items of the class Item_direct_view_ref).
It caused crashes for queries over derived tables or views if the
min/max optimization could be applied to these queries.
This commit is contained in:
Igor Babaev 2011-06-23 14:48:45 -07:00
parent 1f6b32bc37
commit 3cf0d6f446
3 changed files with 39 additions and 4 deletions
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16
mysql-test/r/derived.result
View File

@ -425,3 +425,19 @@ SELECT * FROM (SELECT DISTINCT * FROM t2) t, t1 WHERE t1.a = t.a;
a a
3 3
DROP TABLE t1,t2;
#
# LP bug #800518: crash with a query over a derived table
# when a min/max optimization is applied
#
CREATE TABLE t1 (a int, b int, c varchar(10), INDEX idx(a,b)) ;
INSERT INTO t1 VALUES
(100, 3, 'xxx'), (200, 7, 'yyyyyyy'), (100, 1, 't'),
(200, 4, 'aaaa'), (100, 3, 'eee'), (100, 5, 'zzzzz');
EXPLAIN
SELECT MAX(b) FROM (SELECT * FROM t1) AS t WHERE a = 100;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
SELECT MAX(b) FROM (SELECT * FROM t1) AS t WHERE a = 100;
MAX(b)
5
DROP TABLE t1;

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

@ -331,3 +331,20 @@ SELECT * FROM (SELECT DISTINCT * FROM t2) t, t1 WHERE t1.a = t.a;
SELECT * FROM (SELECT DISTINCT * FROM t2) t, t1 WHERE t1.a = t.a;
DROP TABLE t1,t2;
--echo #
--echo # LP bug #800518: crash with a query over a derived table
--echo # when a min/max optimization is applied
--echo #
CREATE TABLE t1 (a int, b int, c varchar(10), INDEX idx(a,b)) ;
INSERT INTO t1 VALUES
(100, 3, 'xxx'), (200, 7, 'yyyyyyy'), (100, 1, 't'),
(200, 4, 'aaaa'), (100, 3, 'eee'), (100, 5, 'zzzzz');
EXPLAIN
SELECT MAX(b) FROM (SELECT * FROM t1) AS t WHERE a = 100;
SELECT MAX(b) FROM (SELECT * FROM t1) AS t WHERE a = 100;
DROP TABLE t1;

10
sql/opt_sum.cc
View File

@ -494,12 +494,14 @@ bool simple_pred(Item_func *func_item, Item **args, bool *inv_order)
/* MULT_EQUAL_FUNC */
{
Item_equal *item_equal= (Item_equal *) func_item;
Item_equal_fields_iterator it(*item_equal);
args[0]= it++;
if (it++)
return 0;
if (!(args[1]= item_equal->get_const()))
return 0;
Item_equal_fields_iterator it(*item_equal);
if (!(item= it++))
return 0;
args[0]= item->real_item();
if (it++)
return 0;
}
break;
case 1: