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BUG#834739: Wrong result with 3-way inner join, LooseScan,multipart keys

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- Don't use join buffering for tables that are within ranges that are 
  covered by LooseScan strategy.
This commit is contained in:
Sergey Petrunya
2011-09-05 20:51:37 +04:00
parent 6035d0d755
commit e1435a5178
6 changed files with 120 additions and 3 deletions
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41
mysql-test/r/subselect_sj.result
View File

@ -1,4 +1,4 @@
drop table if exists t0, t1, t2, t3, t4, t10, t11, t12;
drop table if exists t0, t1, t2, t3, t4, t5, t10, t11, t12;
drop view if exists v1, v2, v3, v4;
drop procedure if exists p1;
set @subselect_sj_tmp= @@optimizer_switch;
@ -1772,4 +1772,43 @@ b a
5 6
DROP TABLE t1, t2, t3;
set @@optimizer_switch= @tmp835758;
#
# BUG#834739: Wrong result with 3-way inner join, LooseScan,multipart keys
#
set @tmp834739=@@optimizer_switch;
set optimizer_switch='semijoin=on,loosescan=on,materialization=off,firstmatch=off';
CREATE TABLE t2 ( b int, c int, KEY (b)) ;
INSERT INTO t2 VALUES (1,0),(1,0),(9,0),(1,0),(5,0);
CREATE TABLE t3 ( a int);
INSERT INTO t3 VALUES (0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0);
CREATE TABLE t4 ( a int);
INSERT INTO t4 VALUES (0),(0),(0);
CREATE TABLE t5 ( b int, a int , KEY (a,b)) ;
INSERT INTO t5 VALUES (7,0),(9,0);
explain
SELECT * FROM t3 WHERE t3.a IN (SELECT t5.a FROM t2, t4, t5 WHERE t2.c = t5.a AND t2.b = t5.b);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t5 index a a 10 NULL 2 Using where; Using index; LooseScan
1 PRIMARY t4 ALL NULL NULL NULL NULL 3
1 PRIMARY t2 ref b b 5 test.t5.b 2 Using where; FirstMatch(t5)
1 PRIMARY t3 ALL NULL NULL NULL NULL 15 Using where; Using join buffer (flat, BNL join)
SELECT * FROM t3 WHERE t3.a IN (SELECT t5.a FROM t2, t4, t5 WHERE t2.c = t5.a AND t2.b = t5.b);
a
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
DROP TABLE t2, t3, t4, t5;
set @@optimizer_switch=@tmp834739;
set optimizer_switch=@subselect_sj_tmp;

41
mysql-test/r/subselect_sj_jcl6.result
View File

@ -9,7 +9,7 @@ set join_cache_level=6;
show variables like 'join_cache_level';
Variable_name Value
join_cache_level 6
drop table if exists t0, t1, t2, t3, t4, t10, t11, t12;
drop table if exists t0, t1, t2, t3, t4, t5, t10, t11, t12;
drop view if exists v1, v2, v3, v4;
drop procedure if exists p1;
set @subselect_sj_tmp= @@optimizer_switch;
@ -1783,6 +1783,45 @@ b a
5 6
DROP TABLE t1, t2, t3;
set @@optimizer_switch= @tmp835758;
#
# BUG#834739: Wrong result with 3-way inner join, LooseScan,multipart keys
#
set @tmp834739=@@optimizer_switch;
set optimizer_switch='semijoin=on,loosescan=on,materialization=off,firstmatch=off';
CREATE TABLE t2 ( b int, c int, KEY (b)) ;
INSERT INTO t2 VALUES (1,0),(1,0),(9,0),(1,0),(5,0);
CREATE TABLE t3 ( a int);
INSERT INTO t3 VALUES (0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0);
CREATE TABLE t4 ( a int);
INSERT INTO t4 VALUES (0),(0),(0);
CREATE TABLE t5 ( b int, a int , KEY (a,b)) ;
INSERT INTO t5 VALUES (7,0),(9,0);
explain
SELECT * FROM t3 WHERE t3.a IN (SELECT t5.a FROM t2, t4, t5 WHERE t2.c = t5.a AND t2.b = t5.b);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t5 index a a 10 NULL 2 Using where; Using index; LooseScan
1 PRIMARY t4 ALL NULL NULL NULL NULL 3
1 PRIMARY t2 ref b b 5 test.t5.b 2 Using where; FirstMatch(t5)
1 PRIMARY t3 ALL NULL NULL NULL NULL 15 Using where; Using join buffer (flat, BNL join)
SELECT * FROM t3 WHERE t3.a IN (SELECT t5.a FROM t2, t4, t5 WHERE t2.c = t5.a AND t2.b = t5.b);
a
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
DROP TABLE t2, t3, t4, t5;
set @@optimizer_switch=@tmp834739;
set optimizer_switch=@subselect_sj_tmp;
#
# BUG#49129: Wrong result with IN-subquery with join_cache_level=6 and firstmatch=off

26
mysql-test/t/subselect_sj.test
View File

@ -2,7 +2,7 @@
# Nested Loops semi-join subquery evaluation tests
#
--disable_warnings
drop table if exists t0, t1, t2, t3, t4, t10, t11, t12;
drop table if exists t0, t1, t2, t3, t4, t5, t10, t11, t12;
drop view if exists v1, v2, v3, v4;
drop procedure if exists p1;
--enable_warnings
@ -1618,5 +1618,29 @@ SELECT * FROM t1, t2 WHERE (t2.a , t1.b) IN (SELECT a, b FROM t3);
DROP TABLE t1, t2, t3;
set @@optimizer_switch= @tmp835758;
--echo #
--echo # BUG#834739: Wrong result with 3-way inner join, LooseScan,multipart keys
--echo #
set @tmp834739=@@optimizer_switch;
set optimizer_switch='semijoin=on,loosescan=on,materialization=off,firstmatch=off';
CREATE TABLE t2 ( b int, c int, KEY (b)) ;
INSERT INTO t2 VALUES (1,0),(1,0),(9,0),(1,0),(5,0);
CREATE TABLE t3 ( a int);
INSERT INTO t3 VALUES (0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0);
CREATE TABLE t4 ( a int);
INSERT INTO t4 VALUES (0),(0),(0);
CREATE TABLE t5 ( b int, a int , KEY (a,b)) ;
INSERT INTO t5 VALUES (7,0),(9,0);
explain
SELECT * FROM t3 WHERE t3.a IN (SELECT t5.a FROM t2, t4, t5 WHERE t2.c = t5.a AND t2.b = t5.b);
SELECT * FROM t3 WHERE t3.a IN (SELECT t5.a FROM t2, t4, t5 WHERE t2.c = t5.a AND t2.b = t5.b);
DROP TABLE t2, t3, t4, t5;
set @@optimizer_switch=@tmp834739;
# The following command must be the last one the file
set optimizer_switch=@subselect_sj_tmp;

2
sql/opt_subselect.cc
View File

@ -3827,6 +3827,8 @@ int setup_semijoin_dups_elimination(JOIN *join, ulonglong options,
{
/* We jump from the last table to the first one */
tab->loosescan_match_tab= tab + pos->n_sj_tables - 1;
for (uint j= i; j < pos->n_sj_tables; j++)
join->join_tab[j].inside_loosescan_range= TRUE;
/* Calculate key length */
keylen= 0;

10
sql/sql_select.cc
View File

@ -7100,6 +7100,7 @@ get_best_combination(JOIN *join)
goto loop_end; // Handled in make_join_stat..
j->loosescan_match_tab= NULL; //non-nulls will be set later
j->inside_loosescan_range= FALSE;
j->ref.key = -1;
j->ref.key_parts=0;
@ -8984,6 +8985,15 @@ uint check_join_cache_usage(JOIN_TAB *tab,
if (tab->use_quick == 2)
goto no_join_cache;
/*
Don't use join cache if we're inside a join tab range covered by LooseScan
strategy (TODO: LooseScan is very similar to FirstMatch so theoretically it
should be possible to use join buffering in the same way we're using it for
multi-table firstmatch ranges).
*/
if (tab->inside_loosescan_range)
goto no_join_cache;
if (tab->is_inner_table_of_semi_join_with_first_match() &&
!join->allowed_semijoin_with_cache)

3
sql/sql_select.h
View File

@ -347,6 +347,9 @@ typedef struct st_join_table {
NULL - Not doing a loose scan on this join tab.
*/
struct st_join_table *loosescan_match_tab;
/* TRUE <=> we are inside LooseScan range */
bool inside_loosescan_range;
/* Buffer to save index tuple to be able to skip duplicates */
uchar *loosescan_buf;