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Fix bug lp:856152

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Analysis:
The cause of the bug was that the method
subselect_rowid_merge_engine::partial_match()
was not designed for re-execution within the
same query. Specifically, it didn't cleanup
the bitmap of matching keys after completion.

The test query requires double execution of
the IN predicate because it first checks the
predicate as a constant condition. The second
execution during regular execution used the bitmap
of matching keys produced by the first execution
instead of starting with a clean one.

Solution:
Cleanup the bitmap of matching keys at the end of
the partial matching procedure.
This commit is contained in:
unknown 2011-10-04 23:57:46 +03:00
parent 1c47e1ca0d
commit f40f0ff679
3 changed files with 46 additions and 0 deletions
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24
mysql-test/r/subselect_partial_match.result
View file

@ -348,4 +348,28 @@ c
0
0
drop table t1, t2;
#
# LP BUG#856152 Wrong result with NOT IN subquery and partial_match_rowid_merge
#
CREATE TABLE t1 ( f1 integer NOT NULL , f2 integer) ;
INSERT INTO t1 VALUES (3,3),(48,NULL),(49,1);
CREATE TABLE t2 ( f3 int) ;
INSERT INTO t2 VALUES (5);
set @@optimizer_switch='in_to_exists=off,materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off';
EXPLAIN SELECT * FROM t2 WHERE ( 3 , 1 ) NOT IN ( SELECT f1 , f2 FROM t1 );
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 system NULL NULL NULL NULL 1
2 SUBQUERY t1 ALL NULL NULL NULL NULL 3
SELECT * FROM t2 WHERE ( 3 , 1 ) NOT IN ( SELECT f1 , f2 FROM t1 );
f3
5
set @@optimizer_switch='in_to_exists=on,materialization=off';
EXPLAIN SELECT * FROM t2 WHERE ( 3 , 1 ) NOT IN ( SELECT f1 , f2 FROM t1 );
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 system NULL NULL NULL NULL 1
2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 3 Using where
SELECT * FROM t2 WHERE ( 3 , 1 ) NOT IN ( SELECT f1 , f2 FROM t1 );
f3
5
drop table t1, t2;
set @@optimizer_switch=@save_optimizer_switch;

20
mysql-test/t/subselect_partial_match.test
View file

@ -354,4 +354,24 @@ SELECT * FROM t1 WHERE (6, 4 ) NOT IN (SELECT a, b FROM t2);
drop table t1, t2;
--echo #
--echo # LP BUG#856152 Wrong result with NOT IN subquery and partial_match_rowid_merge
--echo #
CREATE TABLE t1 ( f1 integer NOT NULL , f2 integer) ;
INSERT INTO t1 VALUES (3,3),(48,NULL),(49,1);
CREATE TABLE t2 ( f3 int) ;
INSERT INTO t2 VALUES (5);
set @@optimizer_switch='in_to_exists=off,materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off';
EXPLAIN SELECT * FROM t2 WHERE ( 3 , 1 ) NOT IN ( SELECT f1 , f2 FROM t1 );
SELECT * FROM t2 WHERE ( 3 , 1 ) NOT IN ( SELECT f1 , f2 FROM t1 );
set @@optimizer_switch='in_to_exists=on,materialization=off';
EXPLAIN SELECT * FROM t2 WHERE ( 3 , 1 ) NOT IN ( SELECT f1 , f2 FROM t1 );
SELECT * FROM t2 WHERE ( 3 , 1 ) NOT IN ( SELECT f1 , f2 FROM t1 );
drop table t1, t2;
set @@optimizer_switch=@save_optimizer_switch;

2
sql/item_subselect.cc
View file

@ -5674,6 +5674,8 @@ bool subselect_rowid_merge_engine::partial_match()
DBUG_ASSERT(FALSE);
end:
if (!has_covering_null_columns)
bitmap_clear_all(&matching_keys);
queue_remove_all(&pq);
tmp_table->file->ha_rnd_end();
return res;