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BUG#920255: Wrong result (extra rows) with loosescan and IN subquery

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The problem was that LooseScan execution code assumed that tab->key holds 
the index used for looseScan. This is only true when range or full index
scan are used. In case of ref access, the index is in tab->ref.key (and 
tab->index==0 which explains how LooseScan passed tests with ref access: they 
used one index)

Fixed by setting/using loosescan_key, which always the correct index#.
This commit is contained in:
Sergey Petrunya 2012-01-25 18:33:57 +04:00
parent e10816118a
commit 73cc529b51
6 changed files with 96 additions and 2 deletions
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34
mysql-test/r/subselect_sj.result
View file

@ -2169,4 +2169,38 @@ WHERE c = b AND b = a
a COUNT(*)
NULL 0
DROP TABLE t1, t2, t3;
#
# BUG#920255: Wrong result (extra rows) with loosescan and IN subquery
#
CREATE TABLE t1 ( a INT PRIMARY KEY, b INT, KEY(b) );
INSERT INTO t1 VALUES
(1,2),(2,1),(3,3),(4,2),(5,5),
(6,3),(7,1),(8,4),(9,3),(10,2);
CREATE TABLE t2 ( c INT, d INT, UNIQUE KEY(c) );
INSERT INTO t2 VALUES
(1,2),(2,1),(3,3),(4,2),(5,5),(6,3),(7,1);
SELECT a, b, d FROM t1, t2
WHERE ( b, d ) IN
( SELECT b, d FROM t1, t2 WHERE b = c );
a b d
2 1 2
7 1 2
2 1 2
7 1 2
1 2 1
4 2 1
10 2 1
1 2 1
4 2 1
10 2 1
3 3 3
6 3 3
9 3 3
3 3 3
6 3 3
9 3 3
8 4 2
8 4 2
5 5 5
DROP TABLE t1, t2;
set optimizer_switch=@subselect_sj_tmp;

34
mysql-test/r/subselect_sj_jcl6.result
View file

@ -2183,6 +2183,40 @@ WHERE c = b AND b = a
a COUNT(*)
NULL 0
DROP TABLE t1, t2, t3;
#
# BUG#920255: Wrong result (extra rows) with loosescan and IN subquery
#
CREATE TABLE t1 ( a INT PRIMARY KEY, b INT, KEY(b) );
INSERT INTO t1 VALUES
(1,2),(2,1),(3,3),(4,2),(5,5),
(6,3),(7,1),(8,4),(9,3),(10,2);
CREATE TABLE t2 ( c INT, d INT, UNIQUE KEY(c) );
INSERT INTO t2 VALUES
(1,2),(2,1),(3,3),(4,2),(5,5),(6,3),(7,1);
SELECT a, b, d FROM t1, t2
WHERE ( b, d ) IN
( SELECT b, d FROM t1, t2 WHERE b = c );
a b d
1 2 1
1 2 1
2 1 2
2 1 2
3 3 3
3 3 3
4 2 1
4 2 1
5 5 5
6 3 3
6 3 3
7 1 2
7 1 2
8 4 2
8 4 2
9 3 3
9 3 3
10 2 1
10 2 1
DROP TABLE t1, t2;
set optimizer_switch=@subselect_sj_tmp;
#
# BUG#49129: Wrong result with IN-subquery with join_cache_level=6 and firstmatch=off

19
mysql-test/t/subselect_sj.test
View file

@ -2017,5 +2017,24 @@ SELECT a, COUNT(*) FROM t1
DROP TABLE t1, t2, t3;
--echo #
--echo # BUG#920255: Wrong result (extra rows) with loosescan and IN subquery
--echo #
CREATE TABLE t1 ( a INT PRIMARY KEY, b INT, KEY(b) );
INSERT INTO t1 VALUES
(1,2),(2,1),(3,3),(4,2),(5,5),
(6,3),(7,1),(8,4),(9,3),(10,2);
CREATE TABLE t2 ( c INT, d INT, UNIQUE KEY(c) );
INSERT INTO t2 VALUES
(1,2),(2,1),(3,3),(4,2),(5,5),(6,3),(7,1);
SELECT a, b, d FROM t1, t2
WHERE ( b, d ) IN
( SELECT b, d FROM t1, t2 WHERE b = c );
DROP TABLE t1, t2;
# The following command must be the last one the file
set optimizer_switch=@subselect_sj_tmp;

1
sql/opt_subselect.cc
View file

@ -4107,6 +4107,7 @@ int setup_semijoin_dups_elimination(JOIN *join, ulonglong options,
for (uint kp=0; kp < pos->loosescan_picker.loosescan_parts; kp++)
keylen += tab->table->key_info[keyno].key_part[kp].store_length;
tab->loosescan_key= keyno;
tab->loosescan_key_len= keylen;
if (pos->n_sj_tables > 1)
tab[pos->n_sj_tables - 1].do_firstmatch= tab;

4
sql/sql_select.cc
View file

@ -15372,7 +15372,7 @@ sub_select(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
if (join_tab->loosescan_match_tab &&
join_tab->loosescan_match_tab->found_match)
{
KEY *key= join_tab->table->key_info + join_tab->index;
KEY *key= join_tab->table->key_info + join_tab->loosescan_key;
key_copy(join_tab->loosescan_buf, join_tab->table->record[0], key,
join_tab->loosescan_key_len);
skip_over= TRUE;
@ -15382,7 +15382,7 @@ sub_select(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
if (skip_over && !error)
{
if(!key_cmp(join_tab->table->key_info[join_tab->index].key_part,
if(!key_cmp(join_tab->table->key_info[join_tab->loosescan_key].key_part,
join_tab->loosescan_buf, join_tab->loosescan_key_len))
{
/*

6
sql/sql_select.h
View file

@ -379,6 +379,12 @@ typedef struct st_join_table {
/* Buffer to save index tuple to be able to skip duplicates */
uchar *loosescan_buf;
/*
Index used by LooseScan (we store it here separately because ref access
stores it in tab->ref.key, while range scan stores it in tab->index, etc)
*/
uint loosescan_key;
/* Length of key tuple (depends on #keyparts used) to store in the above */
uint loosescan_key_len;