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Backport of the fix for bug #50335 to 5.0.

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The problem was in an incorrect debug assertion. The expression
used in the failing assertion states that when finding
references matching ORDER BY expressions, there can be only one
reference to a single table. But that does not make any sense,
all test cases for this bug are valid examples with multiple
identical WHERE expressions referencing the same table which
are also present in the ORDER BY list.

Fixed by removing the failing assertion. We also have to take
care of the 'found' counter so that we count multiple
references only once. We rely on this fact later in
eq_ref_table().
This commit is contained in:
Alexey Kopytov 2010-04-27 00:06:00 +04:00
parent e085076704
commit 1a1fd04d84
3 changed files with 26 additions and 3 deletions
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10
mysql-test/r/join.result
View file

@ -942,4 +942,14 @@ ROW(t1.b, 1111.11) <=> ROW('','');
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
DROP TABLE t1;
#
# Bug #50335: Assertion `!(order->used & map)' in eq_ref_table
#
CREATE TABLE t1 (a INT NOT NULL, b INT NOT NULL, PRIMARY KEY (a,b));
INSERT INTO t1 VALUES (0,0), (1,1);
SELECT * FROM t1 STRAIGHT_JOIN t1 t2 ON t1.a=t2.a AND t1.a=t2.b ORDER BY t2.a, t1.a;
a b a b
0 0 0 0
1 1 1 1
DROP TABLE t1;
End of 5.0 tests.

11
mysql-test/t/join.test
View file

@ -736,4 +736,15 @@ WHERE ROW(t1.a, 1111.11) = ROW(1111.11, 1111.11) AND
ROW(t1.b, 1111.11) <=> ROW('','');
DROP TABLE t1;
--echo #
--echo # Bug #50335: Assertion `!(order->used & map)' in eq_ref_table
--echo #
CREATE TABLE t1 (a INT NOT NULL, b INT NOT NULL, PRIMARY KEY (a,b));
INSERT INTO t1 VALUES (0,0), (1,1);
SELECT * FROM t1 STRAIGHT_JOIN t1 t2 ON t1.a=t2.a AND t1.a=t2.b ORDER BY t2.a, t1.a;
DROP TABLE t1;
--echo End of 5.0 tests.

8
sql/sql_select.cc
View file

@ -6720,9 +6720,11 @@ eq_ref_table(JOIN *join, ORDER *start_order, JOIN_TAB *tab)
}
if (order)
{
found++;
DBUG_ASSERT(!(order->used & map));
order->used|=map;
if (!(order->used & map))
{
found++;
order->used|= map;
}
continue; // Used in ORDER BY
}
if (!only_eq_ref_tables(join,start_order, (*ref_item)->used_tables()))