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Fixed bug lp:809245

Browse Source 
In addition to the bug fix explained below, the patch performs
few renames, and adds some comments to avoid similar problems.

Analysis:
The failed assert was due to a bug in MWL#68, where it was
incorrectly assumed that the size of the bitmap
subselect_rowid_merge_engine::null_only_columns should be
the same as the size of the array of Ordered_keys.

The bitmap null_only_columns contains bits to mark columns
that contain only NULLs. Therefore the indexes of the bits
to be set in null_only_columns are different from the indexes
of the Ordered_keys. If there is a NULL-only column that appears
in a table after the last partial match column with Ordered_key,
this NULL-only column would require setting a bit with index
bigger than the size of the bitmap null_only_columns.

Accessing such a bit caused the failed assert.

Solution:
Upon analysis, it turns out that null_only_columns is not needed
at all, because we are looking for partial matches, and having
such columns guarantees that there is a partial match for any
corresponding outer value.

Therefore the patch removes
  subselect_rowid_merge_engine::null_only_columns.
This commit is contained in:
unknown
2011-07-13 17:09:09 +03:00
parent d43063939c
commit 990584d73a
4 changed files with 137 additions and 71 deletions
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56
mysql-test/r/subselect_partial_match.result
View File

@ -1,8 +1,8 @@
set @save_optimizer_switch=@@optimizer_switch;
drop table if exists t1, t2;
#
# LP BUG#608744
#
set @save_optimizer_switch=@@optimizer_switch;
set @@optimizer_switch="materialization=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=off";
create table t1 (a1 char(1), a2 char(1));
insert into t1 values (NULL, 'b');
@ -11,7 +11,6 @@ insert into t2 values ('a','b'), ('c', 'd');
select * from t1 where (a1, a2) NOT IN (select b1, b2 from t2);
a1 a2
drop table t1,t2;
set @@optimizer_switch=@save_optimizer_switch;
#
# LP BUG#601156
#
@ -21,7 +20,6 @@ INSERT INTO t1 VALUES (4,NULL);
CREATE TABLE t2 (b1 int DEFAULT NULL, b2 int DEFAULT NULL);
INSERT INTO t2 VALUES (6,NULL);
INSERT INTO t2 VALUES (NULL,0);
set @save_optimizer_switch=@@optimizer_switch;
set @@optimizer_switch='materialization=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on';
EXPLAIN EXTENDED
SELECT * FROM (SELECT * FROM t1 WHERE a1 NOT IN (SELECT b2 FROM t2)) table1;
@ -31,11 +29,9 @@ id select_type table type possible_keys key key_len ref rows filtered Extra
Warnings:
Note 1003 select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` where (not(<in_optimizer>(`test`.`t1`.`a1`,`test`.`t1`.`a1` in ( <materialize> (select `test`.`t2`.`b2` from `test`.`t2` ), <primary_index_lookup>(`test`.`t1`.`a1` in <temporary table> on distinct_key where ((`test`.`t1`.`a1` = `<subquery3>`.`b2`)))))))
DROP TABLE t1, t2;
set @@optimizer_switch=@save_optimizer_switch;
#
# LP BUG#613009 Crash in Ordered_key::get_field_idx
#
set @save_optimizer_switch=@@optimizer_switch;
set @@optimizer_switch='materialization=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=off';
create table t1 (a1 char(3) DEFAULT NULL, a2 char(3) DEFAULT NULL);
insert into t1 values (NULL, 'a21'), (NULL, 'a22');
@ -46,7 +42,6 @@ id select_type table type possible_keys key key_len ref rows Extra
select * from t1 where (a1, a2) not in (select a1, a2 from t1);
a1 a2
drop table t1;
set @@optimizer_switch=@save_optimizer_switch;
#
# LP BUG#680058 void Ordered_key::add_key(rownum_t):
# Assertion `key_buff_elements && cur_key_idx < key_buff_elements' failed
@ -55,10 +50,53 @@ create table t1 (f1 char(1), f2 char(1));
insert into t1 values ('t', '0'), ('0', 't');
create table t2 (f3 char(1), f4 char(1));
insert into t2 values ('t', NULL), ('t', NULL), ('d', 'y');
set @save_optimizer_switch=@@optimizer_switch;
SET @@optimizer_switch='materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off,semijoin=off';
set @@optimizer_switch='materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off,semijoin=off';
select * from t1 where (f1, f2) not in (select * from t2);
f1 f2
0 t
set @@optimizer_switch=@save_optimizer_switch;
drop table t1, t2;
#
# LP BUG#809245 Second assertion `bit < (map)->n_bits' with partial_match_merge
#
CREATE TABLE t1 (d varchar(32)) ;
INSERT INTO t1 VALUES ('r');
CREATE TABLE t2 ( a int, c varchar(32)) ;
INSERT INTO t2 VALUES (5,'r');
CREATE TABLE t3 ( a int NOT NULL , d varchar(32)) ;
INSERT INTO t3 VALUES (10,'g');
set @@optimizer_switch='materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off,in_to_exists=off';
EXPLAIN SELECT *
FROM t1
WHERE (t1.d , t1.d) NOT IN (
SELECT t3.d , t2.c
FROM t3 LEFT JOIN t2 ON t3.a = t2.a);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 system NULL NULL NULL NULL 1
2 SUBQUERY t3 system NULL NULL NULL NULL 1
2 SUBQUERY t2 system NULL NULL NULL NULL 1
SELECT *
FROM t1
WHERE (t1.d , t1.d) NOT IN (
SELECT t3.d , t2.c
FROM t3 LEFT JOIN t2 ON t3.a = t2.a);
d
r
set @@optimizer_switch='materialization=off,in_to_exists=on';
EXPLAIN SELECT *
FROM t1
WHERE (t1.d , t1.d) NOT IN (
SELECT t3.d , t2.c
FROM t3 LEFT JOIN t2 ON t3.a = t2.a);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 system NULL NULL NULL NULL 1
2 DEPENDENT SUBQUERY t3 system NULL NULL NULL NULL 1
2 DEPENDENT SUBQUERY t2 system NULL NULL NULL NULL 1
SELECT *
FROM t1
WHERE (t1.d , t1.d) NOT IN (
SELECT t3.d , t2.c
FROM t3 LEFT JOIN t2 ON t3.a = t2.a);
d
r
drop table t1, t2, t3;
set @@optimizer_switch=@save_optimizer_switch;

58
mysql-test/t/subselect_partial_match.test
View File

@ -3,6 +3,8 @@
# MWL#68: Subquery optimization: Efficient NOT IN execution with NULLs
#
set @save_optimizer_switch=@@optimizer_switch;
--disable_warnings
drop table if exists t1, t2;
--enable_warnings
@ -10,7 +12,6 @@ drop table if exists t1, t2;
--echo #
--echo # LP BUG#608744
--echo #
set @save_optimizer_switch=@@optimizer_switch;
set @@optimizer_switch="materialization=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=off";
create table t1 (a1 char(1), a2 char(1));
insert into t1 values (NULL, 'b');
@ -18,7 +19,6 @@ create table t2 (b1 char(1), b2 char(2));
insert into t2 values ('a','b'), ('c', 'd');
select * from t1 where (a1, a2) NOT IN (select b1, b2 from t2);
drop table t1,t2;
set @@optimizer_switch=@save_optimizer_switch;
--echo #
@ -32,20 +32,17 @@ CREATE TABLE t2 (b1 int DEFAULT NULL, b2 int DEFAULT NULL);
INSERT INTO t2 VALUES (6,NULL);
INSERT INTO t2 VALUES (NULL,0);
set @save_optimizer_switch=@@optimizer_switch;
set @@optimizer_switch='materialization=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on';
EXPLAIN EXTENDED
SELECT * FROM (SELECT * FROM t1 WHERE a1 NOT IN (SELECT b2 FROM t2)) table1;
DROP TABLE t1, t2;
set @@optimizer_switch=@save_optimizer_switch;
--echo #
--echo # LP BUG#613009 Crash in Ordered_key::get_field_idx
--echo #
set @save_optimizer_switch=@@optimizer_switch;
set @@optimizer_switch='materialization=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=off';
create table t1 (a1 char(3) DEFAULT NULL, a2 char(3) DEFAULT NULL);
@ -53,7 +50,6 @@ insert into t1 values (NULL, 'a21'), (NULL, 'a22');
explain select * from t1 where (a1, a2) not in (select a1, a2 from t1);
select * from t1 where (a1, a2) not in (select a1, a2 from t1);
drop table t1;
set @@optimizer_switch=@save_optimizer_switch;
--echo #
--echo # LP BUG#680058 void Ordered_key::add_key(rownum_t):
@ -65,8 +61,52 @@ insert into t1 values ('t', '0'), ('0', 't');
create table t2 (f3 char(1), f4 char(1));
insert into t2 values ('t', NULL), ('t', NULL), ('d', 'y');
set @save_optimizer_switch=@@optimizer_switch;
SET @@optimizer_switch='materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off,semijoin=off';
set @@optimizer_switch='materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off,semijoin=off';
select * from t1 where (f1, f2) not in (select * from t2);
set @@optimizer_switch=@save_optimizer_switch;
drop table t1, t2;
--echo #
--echo # LP BUG#809245 Second assertion `bit < (map)->n_bits' with partial_match_merge
--echo #
CREATE TABLE t1 (d varchar(32)) ;
INSERT INTO t1 VALUES ('r');
CREATE TABLE t2 ( a int, c varchar(32)) ;
INSERT INTO t2 VALUES (5,'r');
CREATE TABLE t3 ( a int NOT NULL , d varchar(32)) ;
INSERT INTO t3 VALUES (10,'g');
set @@optimizer_switch='materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off,in_to_exists=off';
EXPLAIN SELECT *
FROM t1
WHERE (t1.d , t1.d) NOT IN (
SELECT t3.d , t2.c
FROM t3 LEFT JOIN t2 ON t3.a = t2.a);
SELECT *
FROM t1
WHERE (t1.d , t1.d) NOT IN (
SELECT t3.d , t2.c
FROM t3 LEFT JOIN t2 ON t3.a = t2.a);
set @@optimizer_switch='materialization=off,in_to_exists=on';
EXPLAIN SELECT *
FROM t1
WHERE (t1.d , t1.d) NOT IN (
SELECT t3.d , t2.c
FROM t3 LEFT JOIN t2 ON t3.a = t2.a);
SELECT *
FROM t1
WHERE (t1.d , t1.d) NOT IN (
SELECT t3.d , t2.c
FROM t3 LEFT JOIN t2 ON t3.a = t2.a);
drop table t1, t2, t3;
set @@optimizer_switch=@save_optimizer_switch;