At file:///home/psergey/dev/maria-5.3-subqueries-r7/
------------------------------------------------------------
revno: 2773
revision-id: psergey@askmonty.org-20100307154145-ksby2b1l0sqm1xne
parent: igor@askmonty.org-20100306191455-g2srime08w9u6l49
committer: Sergey Petrunya
branch nick: maria-5.3-subqueries-r7
timestamp: Sun 2010-03-07 18:41:45 +0300
message:
BUG#49129: Wrong result with IN-subquery with join_cache_level=6 and firstmatch=off
- The problem was that DuplicateWeedout strategy setup code wasn't aware of the
fact that join buffering will be used and applied optimization that doesn't work
together with join buffering. Fixed by making DuplicateWeedout setup code to have
a pessimistic check about whether there is a chance that join buffering will be
used.
- Make JOIN_CACHE_BKA::init() correctly process Copy_field elements that denote saving
current rowids in the join buffer.
=== modified file 'mysql-test/r/subselect_sj2.result'
--- a/mysql-test/r/subselect_sj2.result 2010-02-17 10:47:55 +0000
+++ b/mysql-test/r/subselect_sj2.result 2010-03-07 15:41:45 +0000
@@ -264,8 +264,8 @@
from t0 where a in
(select t2.a+t3.a from t1 left join (t2 join t3) on t2.a=t1.a and t3.a=t1.a);
id select_type table type possible_keys key key_len ref rows Extra
-1 PRIMARY t0 ALL NULL NULL NULL NULL 10
-1 PRIMARY t1 index NULL a 5 NULL 10 Using index; Start temporary; Using join buffer
+1 PRIMARY t0 ALL NULL NULL NULL NULL 10 Start temporary
+1 PRIMARY t1 index NULL a 5 NULL 10 Using index; Using join buffer
1 PRIMARY t2 ref a a 5 test.t1.a 1 Using index
1 PRIMARY t3 ref a a 5 test.t1.a 1 Using where; Using index; End temporary
drop table t0, t1,t2,t3;
=== modified file 'mysql-test/r/subselect_sj2_jcl6.result'
--- a/mysql-test/r/subselect_sj2_jcl6.result 2010-03-05 18:54:48 +0000
+++ b/mysql-test/r/subselect_sj2_jcl6.result 2010-03-07 15:41:45 +0000
@@ -268,8 +268,8 @@
from t0 where a in
(select t2.a+t3.a from t1 left join (t2 join t3) on t2.a=t1.a and t3.a=t1.a);
id select_type table type possible_keys key key_len ref rows Extra
-1 PRIMARY t0 ALL NULL NULL NULL NULL 10
-1 PRIMARY t1 index NULL a 5 NULL 10 Using index; Start temporary; Using join buffer
+1 PRIMARY t0 ALL NULL NULL NULL NULL 10 Start temporary
+1 PRIMARY t1 index NULL a 5 NULL 10 Using index; Using join buffer
1 PRIMARY t2 ref a a 5 test.t1.a 1 Using index
1 PRIMARY t3 ref a a 5 test.t1.a 1 Using where; Using index; End temporary
drop table t0, t1,t2,t3;
@@ -421,20 +421,23 @@
where t0.a in ( select t1.a from t1,t2 where t2.a=t0.a and
t1.b=t2.b);
id select_type table type possible_keys key key_len ref rows filtered Extra
-1 PRIMARY t0 ALL NULL NULL NULL NULL 5 100.00
-1 PRIMARY t1 ref a a 5 test.t0.a 1 100.00 Start temporary; Using join buffer
+1 PRIMARY t0 ALL NULL NULL NULL NULL 5 100.00 Start temporary
+1 PRIMARY t1 ref a a 5 test.t0.a 1 100.00 Using join buffer
1 PRIMARY t2 eq_ref PRIMARY PRIMARY 4 test.t0.a 1 100.00 Using where; End temporary; Using join buffer
Warnings:
Note 1276 Field or reference 'test.t0.a' of SELECT #2 was resolved in SELECT #1
Note 1003 select `test`.`t0`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) join `test`.`t0` where ((`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t1`.`a` = `test`.`t0`.`a`) and (`test`.`t2`.`a` = `test`.`t0`.`a`))
update t1 set a=3, b=11 where a=4;
update t2 set b=11 where a=3;
-
+# Not anymore:
# The following query gives wrong result due to Bug#49129
select * from t0 where t0.a in
(select t1.a from t1, t2 where t2.a=t0.a and t1.b=t2.b);
a
0
+1
+2
+3
drop table t0, t1, t2;
CREATE TABLE t1 (
id int(11) NOT NULL,
=== modified file 'mysql-test/r/subselect_sj_jcl6.result'
--- a/mysql-test/r/subselect_sj_jcl6.result 2010-03-05 18:54:48 +0000
+++ b/mysql-test/r/subselect_sj_jcl6.result 2010-03-07 15:41:45 +0000
@@ -875,6 +875,37 @@
DROP TABLE t1, t2, t3;
DROP VIEW v2, v3;
# End of Bug#49198
+#
+# BUG#49129: Wrong result with IN-subquery with join_cache_level=6 and firstmatch=off
+#
+CREATE TABLE t0 (a INT);
+INSERT INTO t0 VALUES (0),(1),(2),(3),(4);
+CREATE TABLE t1 (a INT, b INT, KEY(a));
+INSERT INTO t1 SELECT a, a from t0;
+CREATE TABLE t2 (a INT, b INT, PRIMARY KEY(a));
+INSERT INTO t2 SELECT * FROM t1;
+UPDATE t1 SET a=3, b=11 WHERE a=4;
+UPDATE t2 SET b=11 WHERE a=3;
+set @save_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='firstmatch=off';
+The following should use a join order of t0,t1,t2, with DuplicateElimination:
+explain
+SELECT * FROM t0 WHERE t0.a IN
+(SELECT t1.a FROM t1, t2 WHERE t2.a=t0.a AND t1.b=t2.b);
+id select_type table type possible_keys key key_len ref rows Extra
+1 PRIMARY t0 ALL NULL NULL NULL NULL 5 Start temporary
+1 PRIMARY t1 ref a a 5 test.t0.a 1 Using join buffer
+1 PRIMARY t2 eq_ref PRIMARY PRIMARY 4 test.t0.a 1 Using where; End temporary; Using join buffer
+SELECT * FROM t0 WHERE t0.a IN
+(SELECT t1.a FROM t1, t2 WHERE t2.a=t0.a AND t1.b=t2.b);
+a
+0
+1
+2
+3
+set optimizer_switch=@save_optimizer_switch;
+drop table t0, t1, t2;
+# End
set join_cache_level=default;
show variables like 'join_cache_level';
Variable_name Value
=== modified file 'mysql-test/t/subselect_sj2.test'
--- a/mysql-test/t/subselect_sj2.test 2010-01-17 14:51:10 +0000
+++ b/mysql-test/t/subselect_sj2.test 2010-03-07 15:41:45 +0000
@@ -583,7 +583,7 @@
if (`select @@join_cache_level=6`)
{
- --echo
+ --echo # Not anymore:
--echo # The following query gives wrong result due to Bug#49129
}
select * from t0 where t0.a in
=== modified file 'mysql-test/t/subselect_sj_jcl6.test'
--- a/mysql-test/t/subselect_sj_jcl6.test 2010-01-17 14:51:10 +0000
+++ b/mysql-test/t/subselect_sj_jcl6.test 2010-03-07 15:41:45 +0000
@@ -7,5 +7,33 @@
--source t/subselect_sj.test
+--echo #
+--echo # BUG#49129: Wrong result with IN-subquery with join_cache_level=6 and firstmatch=off
+--echo #
+CREATE TABLE t0 (a INT);
+INSERT INTO t0 VALUES (0),(1),(2),(3),(4);
+CREATE TABLE t1 (a INT, b INT, KEY(a));
+INSERT INTO t1 SELECT a, a from t0;
+CREATE TABLE t2 (a INT, b INT, PRIMARY KEY(a));
+INSERT INTO t2 SELECT * FROM t1;
+UPDATE t1 SET a=3, b=11 WHERE a=4;
+UPDATE t2 SET b=11 WHERE a=3;
+
+set @save_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='firstmatch=off';
+
+--echo The following should use a join order of t0,t1,t2, with DuplicateElimination:
+explain
+SELECT * FROM t0 WHERE t0.a IN
+ (SELECT t1.a FROM t1, t2 WHERE t2.a=t0.a AND t1.b=t2.b);
+
+SELECT * FROM t0 WHERE t0.a IN
+ (SELECT t1.a FROM t1, t2 WHERE t2.a=t0.a AND t1.b=t2.b);
+
+set optimizer_switch=@save_optimizer_switch;
+drop table t0, t1, t2;
+
+--echo # End
+
set join_cache_level=default;
show variables like 'join_cache_level';
=== modified file 'sql/opt_subselect.cc'
--- a/sql/opt_subselect.cc 2010-02-25 08:09:10 +0000
+++ b/sql/opt_subselect.cc 2010-03-07 15:41:45 +0000
@@ -3035,10 +3035,24 @@
forwards, but do not destroy other duplicate elimination methods.
*/
uint first_table= i;
+ uint join_cache_level= join->thd->variables.join_cache_level;
for (uint j= i; j < i + pos->n_sj_tables; j++)
{
- if (join->best_positions[j].use_join_buffer && j <= no_jbuf_after)
+ /*
+ When we'll properly take join buffering into account during
+ join optimization, the below check should be changed to
+ "if (join->best_positions[j].use_join_buffer &&
+ j <= no_jbuf_after)".
+ For now, use a rough criteria:
+ */
+ JOIN_TAB *js_tab=join->join_tab + j;
+ if (j != join->const_tables && js_tab->use_quick != 2 &&
+ j <= no_jbuf_after &&
+ ((js_tab->type == JT_ALL && join_cache_level != 0) ||
+ (join_cache_level > 4 && (tab->type == JT_REF ||
+ tab->type == JT_EQ_REF))))
{
+ /* Looks like we'll be using join buffer */
first_table= join->const_tables;
break;
}
@@ -3116,7 +3130,12 @@
JOIN_TAB *j, *jump_to= tab-1;
for (j= tab; j != tab + pos->n_sj_tables; j++)
{
- if (!tab->emb_sj_nest)
+ /*
+ NOTE: this loop probably doesn't do the right thing for the case
+ where FirstMatch's duplicate-generating range is interleaved with
+ "unrelated" tables (as specified in WL#3750, section 2.2).
+ */
+ if (!j->emb_sj_nest)
jump_to= tab;
else
{
=== modified file 'sql/sql_join_cache.cc'
--- a/sql/sql_join_cache.cc 2010-03-06 19:14:55 +0000
+++ b/sql/sql_join_cache.cc 2010-03-07 15:41:45 +0000
@@ -608,7 +608,12 @@
copy_end= cache->field_descr+cache->fields;
for (copy= cache->field_descr+cache->flag_fields; copy < copy_end; copy++)
{
- if (copy->field->table == tab->table &&
+ /*
+ (1) - when we store rowids for DuplicateWeedout, they have
+ copy->field==NULL
+ */
+ if (copy->field && // (1)
+ copy->field->table == tab->table &&
bitmap_is_set(key_read_set, copy->field->field_index))
{
*copy_ptr++= copy;
=== modified file 'sql/sql_select.cc'
--- a/sql/sql_select.cc 2010-03-05 18:54:48 +0000
+++ b/sql/sql_select.cc 2010-03-07 15:41:45 +0000
@@ -5632,7 +5632,11 @@
uint blob_length=(uint) (join_tab->table->file->stats.mean_rec_length-
(join_tab->table->s->reclength-rec_length));
rec_length+=(uint) max(4,blob_length);
- }
+ }
+ /*
+ psergey-todo: why we don't count here rowid that we might need to store
+ when using DuplicateElimination?
+ */
join_tab->used_fields=fields;
join_tab->used_fieldlength=rec_length;
join_tab->used_blobs=blobs;
