At file:///home/psergey/dev/maria-5.3-subqueries-r6/
------------------------------------------------------------
revno: 2752
revision-id: [email protected]
parent: [email protected]
committer: Sergey Petrunya <[email protected]>
branch nick: maria-5.3-subqueries-r6
timestamp: Fri 2010-02-12 00:58:23 +0300
message:
Apply Jorgen Loland's fix: Bug#45221: Query "SELECT pk FROM C WHERE pk IN
(SELECT int_key)" failing
XOR conditions are not optimized, and Item_cond_xor therefore
acts like type Func_item even though it inherits from Item_cond.
A subtle difference between Item_func and Item_cond is that
you can get the children Items from the former by calling
arguments(), and from the latter by calling argument_list().
However, since Item_cond_xor inherits from Item_cond,
arguments() did not return any Items.
The fact that Item_cond_xor::arguments() did not return it's
children items lead to a problem for make_cond_for_index();
the method accepted that XOR items on unindexed columns were
pushed using ICP. ICP evaluation of non-indexed columns
does not (and should not) work.
The fix for this bug is to make Item_cond_xor return it's
children items when the arguments() method is used. This makes
Item_cond_xor behave more like Item_func and in turn allows
make_cond_for_index() to discover any conflicting children
Items.
This is a temporary fix and should be removed when Item_cond_xor
is optimized.
=== modified file 'mysql-test/r/group_by.result'
--- a/mysql-test/r/group_by.result 2009-02-26 17:17:06 +0000
+++ b/mysql-test/r/group_by.result 2010-02-11 21:58:23 +0000
@@ -1542,8 +1542,8 @@
EXPLAIN SELECT 1 FROM t1 WHERE a IN
(SELECT a FROM t1 USE INDEX (i2) IGNORE INDEX (i2));
id select_type table type possible_keys key key_len ref
rows Extra
-1 PRIMARY t1 index NULL PRIMARY 4 NULL 144 Using
where; Using index
-2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL
144 Using where
+1 PRIMARY t1 index PRIMARY,i2 PRIMARY 4 NULL 144
Using index
+1 PRIMARY t1 ALL NULL NULL NULL NULL 144 Using
where; FirstMatch(t1)
CREATE TABLE t2 (a INT, b INT, KEY(a));
INSERT INTO t2 VALUES (1, 1), (2, 2), (3,3), (4,4);
EXPLAIN SELECT a, SUM(b) FROM t2 GROUP BY a LIMIT 2;
@@ -1555,8 +1555,8 @@
EXPLAIN SELECT 1 FROM t2 WHERE a IN
(SELECT a FROM t1 USE INDEX (i2) IGNORE INDEX (i2));
id select_type table type possible_keys key key_len ref
rows Extra
-1 PRIMARY t2 index NULL a 5 NULL 4 Using
where; Using index
-2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL
144 Using where
+1 PRIMARY t2 index a a 5 NULL 4 Using
index
+1 PRIMARY t1 ALL NULL NULL NULL NULL 144 Using
where; FirstMatch(t2)
SHOW VARIABLES LIKE 'old';
Variable_name Value
old OFF
=== modified file 'sql/item_cmpfunc.h'
--- a/sql/item_cmpfunc.h 2010-01-17 14:55:08 +0000
+++ b/sql/item_cmpfunc.h 2010-02-11 21:58:23 +0000
@@ -1715,14 +1715,34 @@
class Item_cond_xor :public Item_cond
{
public:
- Item_cond_xor() :Item_cond() {}
- Item_cond_xor(Item *i1,Item *i2) :Item_cond(i1,i2) {}
+ Item_cond_xor(Item *i1,Item *i2) :Item_cond(i1,i2)
+ {
+ /*
+ Items must be stored in args[] as well because this Item_cond is
+ treated as a FUNC_ITEM (see type()). I.e., users of it will get
+ it's children by calling arguments(), not argument_list(). This
+ is a temporary solution until XOR is optimized and treated like
+ a full Item_cond citizen.
+ */
+ arg_count= 2;
+ args= tmp_arg;
+ args[0]= i1;
+ args[1]= i2;
+ }
enum Functype functype() const { return COND_XOR_FUNC; }
/* TODO: remove the next line when implementing XOR optimization */
enum Type type() const { return FUNC_ITEM; }
longlong val_int();
const char *func_name() const { return "xor"; }
void top_level_item() {}
+ /* Since child Items are stored in args[], Items cannot be added.
+ However, since Item_cond_xor is treated as a FUNC_ITEM (see
+ type()), the methods below should never be called.
+ */
+ bool add(Item *item) { DBUG_ASSERT(FALSE); return FALSE; }
+ bool add_at_head(Item *item) { DBUG_ASSERT(FALSE); return FALSE; }
+ bool add_at_head(List<Item> *nlist) { DBUG_ASSERT(FALSE); return FALSE; }
+ void copy_andor_arguments(THD *thd, Item_cond *item) { DBUG_ASSERT(FALSE); }
};
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