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BUG#962667: Assertion `0' failed in QUICK_INDEX_SORT_SELECT::need_sorted_output()

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- The problem was that
  = we've picked a LooseScan that used full index scan (tab->type==JT_ALL) on certain index.
  = there was also a quick select (tab->quick!=NULL), that used other indexes.
  = some old code assumes that (tab->type==JT_ALL && tab->quick) -> means that the
    quick select should be used, which is not true.
Fixed by discarding the quick select as soon as we know we're using LooseScan
without using the quick select.
This commit is contained in:
Sergey Petrunya 2012-03-25 18:31:35 +04:00
parent f72e0e686b
commit d054709827
5 changed files with 164 additions and 0 deletions
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37
mysql-test/r/subselect_sj2.result
View file

@ -903,5 +903,42 @@ a b c
3 1 1 3 1 1
4 1 1 4 1 1
DROP TABLE t1,t2; DROP TABLE t1,t2;
#
# BUG#962667: Assertion `0' failed in QUICK_INDEX_SORT_SELECT::need_sorted_output()
# with index_merge+index_merge_sort_union+loosescan+semijoin
#
CREATE TABLE t1 (
a INT, b VARCHAR(1), c INT,
KEY(a), KEY(b)
) ENGINE=InnoDB;
INSERT INTO t1 VALUES
(1,'v',9),(2,'v',8),(3,'c',7),(4,'m',6),(5,'x',5),
(6,'i',4),(7,'e',3),(8,'p',2),(9,'s',1),(10,'j',9),
(11,'z',8),(12,'c',7),(13,'a',6),(14,'q',5),(15,'y',4),
(16,'n',3),(17,'r',2),(18,'v',1),(19,'p',0);
CREATE TABLE t2 (
pk INT, d VARCHAR(1), e INT,
PRIMARY KEY(pk), KEY(d,e)
) ENGINE=InnoDB;
INSERT INTO t2 VALUES
(1,'x',1),(2,'d',2),(3,'r',3),(4,'f',4),(5,'y',5),
(6,'u',6),(7,'m',7),(8,'k',8),(9,'o',9),(10,'w',1),
(11,'m',2),(12,'q',3),(13,'m',4),(14,'d',5),
(15,'g',6),(16,'x',7),(17,'f',8);
explain
SELECT * FROM t1 WHERE b IN (
SELECT d FROM t2, t1
WHERE a = d AND ( pk < 2 OR d = 'z' )
);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 index PRIMARY,d d 9 NULL 17 Using where; Using index; LooseScan
1 PRIMARY t1 ref a a 5 test.t2.d 1 Using where; Using index; FirstMatch(t2)
1 PRIMARY t1 ref b b 4 test.t2.d 1
SELECT * FROM t1 WHERE b IN (
SELECT d FROM t2, t1
WHERE a = d AND ( pk < 2 OR d = 'z' )
);
a b c
DROP TABLE t1, t2;
# This must be the last in the file: # This must be the last in the file:
set optimizer_switch=@subselect_sj2_tmp; set optimizer_switch=@subselect_sj2_tmp;

37
mysql-test/r/subselect_sj2_jcl6.result
View file

@ -917,6 +917,43 @@ a b c
3 1 1 3 1 1
4 1 1 4 1 1
DROP TABLE t1,t2; DROP TABLE t1,t2;
#
# BUG#962667: Assertion `0' failed in QUICK_INDEX_SORT_SELECT::need_sorted_output()
# with index_merge+index_merge_sort_union+loosescan+semijoin
#
CREATE TABLE t1 (
a INT, b VARCHAR(1), c INT,
KEY(a), KEY(b)
) ENGINE=InnoDB;
INSERT INTO t1 VALUES
(1,'v',9),(2,'v',8),(3,'c',7),(4,'m',6),(5,'x',5),
(6,'i',4),(7,'e',3),(8,'p',2),(9,'s',1),(10,'j',9),
(11,'z',8),(12,'c',7),(13,'a',6),(14,'q',5),(15,'y',4),
(16,'n',3),(17,'r',2),(18,'v',1),(19,'p',0);
CREATE TABLE t2 (
pk INT, d VARCHAR(1), e INT,
PRIMARY KEY(pk), KEY(d,e)
) ENGINE=InnoDB;
INSERT INTO t2 VALUES
(1,'x',1),(2,'d',2),(3,'r',3),(4,'f',4),(5,'y',5),
(6,'u',6),(7,'m',7),(8,'k',8),(9,'o',9),(10,'w',1),
(11,'m',2),(12,'q',3),(13,'m',4),(14,'d',5),
(15,'g',6),(16,'x',7),(17,'f',8);
explain
SELECT * FROM t1 WHERE b IN (
SELECT d FROM t2, t1
WHERE a = d AND ( pk < 2 OR d = 'z' )
);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 index PRIMARY,d d 9 NULL 17 Using where; Using index; LooseScan
1 PRIMARY t1 ref a a 5 test.t2.d 1 Using where; Using index; FirstMatch(t2)
1 PRIMARY t1 ref b b 4 test.t2.d 1 Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
SELECT * FROM t1 WHERE b IN (
SELECT d FROM t2, t1
WHERE a = d AND ( pk < 2 OR d = 'z' )
);
a b c
DROP TABLE t1, t2;
# This must be the last in the file: # This must be the last in the file:
set optimizer_switch=@subselect_sj2_tmp; set optimizer_switch=@subselect_sj2_tmp;
# #

37
mysql-test/r/subselect_sj2_mat.result
View file

@ -905,6 +905,43 @@ a b c
3 1 1 3 1 1
4 1 1 4 1 1
DROP TABLE t1,t2; DROP TABLE t1,t2;
#
# BUG#962667: Assertion `0' failed in QUICK_INDEX_SORT_SELECT::need_sorted_output()
# with index_merge+index_merge_sort_union+loosescan+semijoin
#
CREATE TABLE t1 (
a INT, b VARCHAR(1), c INT,
KEY(a), KEY(b)
) ENGINE=InnoDB;
INSERT INTO t1 VALUES
(1,'v',9),(2,'v',8),(3,'c',7),(4,'m',6),(5,'x',5),
(6,'i',4),(7,'e',3),(8,'p',2),(9,'s',1),(10,'j',9),
(11,'z',8),(12,'c',7),(13,'a',6),(14,'q',5),(15,'y',4),
(16,'n',3),(17,'r',2),(18,'v',1),(19,'p',0);
CREATE TABLE t2 (
pk INT, d VARCHAR(1), e INT,
PRIMARY KEY(pk), KEY(d,e)
) ENGINE=InnoDB;
INSERT INTO t2 VALUES
(1,'x',1),(2,'d',2),(3,'r',3),(4,'f',4),(5,'y',5),
(6,'u',6),(7,'m',7),(8,'k',8),(9,'o',9),(10,'w',1),
(11,'m',2),(12,'q',3),(13,'m',4),(14,'d',5),
(15,'g',6),(16,'x',7),(17,'f',8);
explain
SELECT * FROM t1 WHERE b IN (
SELECT d FROM t2, t1
WHERE a = d AND ( pk < 2 OR d = 'z' )
);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 index PRIMARY,d d 9 NULL 17 Using where; Using index; LooseScan
1 PRIMARY t1 ref a a 5 test.t2.d 1 Using where; Using index; FirstMatch(t2)
1 PRIMARY t1 ref b b 4 test.t2.d 1
SELECT * FROM t1 WHERE b IN (
SELECT d FROM t2, t1
WHERE a = d AND ( pk < 2 OR d = 'z' )
);
a b c
DROP TABLE t1, t2;
# This must be the last in the file: # This must be the last in the file:
set optimizer_switch=@subselect_sj2_tmp; set optimizer_switch=@subselect_sj2_tmp;
set optimizer_switch=default; set optimizer_switch=default;

38
mysql-test/t/subselect_sj2.test
View file

@ -1090,5 +1090,43 @@ SELECT * FROM t1, t2 WHERE c IN (SELECT c FROM t1, t2 WHERE a = b);
DROP TABLE t1,t2; DROP TABLE t1,t2;
--echo #
--echo # BUG#962667: Assertion `0' failed in QUICK_INDEX_SORT_SELECT::need_sorted_output()
--echo # with index_merge+index_merge_sort_union+loosescan+semijoin
--echo #
CREATE TABLE t1 (
a INT, b VARCHAR(1), c INT,
KEY(a), KEY(b)
) ENGINE=InnoDB;
INSERT INTO t1 VALUES
(1,'v',9),(2,'v',8),(3,'c',7),(4,'m',6),(5,'x',5),
(6,'i',4),(7,'e',3),(8,'p',2),(9,'s',1),(10,'j',9),
(11,'z',8),(12,'c',7),(13,'a',6),(14,'q',5),(15,'y',4),
(16,'n',3),(17,'r',2),(18,'v',1),(19,'p',0);
CREATE TABLE t2 (
pk INT, d VARCHAR(1), e INT,
PRIMARY KEY(pk), KEY(d,e)
) ENGINE=InnoDB;
INSERT INTO t2 VALUES
(1,'x',1),(2,'d',2),(3,'r',3),(4,'f',4),(5,'y',5),
(6,'u',6),(7,'m',7),(8,'k',8),(9,'o',9),(10,'w',1),
(11,'m',2),(12,'q',3),(13,'m',4),(14,'d',5),
(15,'g',6),(16,'x',7),(17,'f',8);
explain
SELECT * FROM t1 WHERE b IN (
SELECT d FROM t2, t1
WHERE a = d AND ( pk < 2 OR d = 'z' )
);
SELECT * FROM t1 WHERE b IN (
SELECT d FROM t2, t1
WHERE a = d AND ( pk < 2 OR d = 'z' )
);
DROP TABLE t1, t2;
--echo # This must be the last in the file: --echo # This must be the last in the file:
set optimizer_switch=@subselect_sj2_tmp; set optimizer_switch=@subselect_sj2_tmp;

15
sql/opt_subselect.cc
View file

@ -3083,7 +3083,22 @@ void fix_semijoin_strategies_for_picked_join_order(JOIN *join)
record_count, join->best_positions + idx, record_count, join->best_positions + idx,
&loose_scan_pos); &loose_scan_pos);
if (idx==first) if (idx==first)
{
join->best_positions[idx]= loose_scan_pos; join->best_positions[idx]= loose_scan_pos;
/*
If LooseScan is based on ref access (including the "degenerate"
one with 0 key parts), we should use full index scan.
Unfortunately, lots of code assumes that if tab->type==JT_ALL &&
tab->quick!=NULL, then quick select should be used. The only
simple way to fix this is to remove the quick select:
*/
if (join->best_positions[idx].key)
{
delete join->best_positions[idx].table->quick;
join->best_positions[idx].table->quick= NULL;
}
}
} }
rem_tables &= ~join->best_positions[idx].table->table->map; rem_tables &= ~join->best_positions[idx].table->table->map;
record_count *= join->best_positions[idx].records_read; record_count *= join->best_positions[idx].records_read;