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MWL#17: Table elimination:

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- Fix a trivial problem when OR-merging two multi-equalities
- Amend testsuite to provide full gcov coverage

mysql-test/r/table_elim.result:
  MWL#17: Table elimination:
  - Amend testsuite to provide full gcov coverage
mysql-test/t/table_elim.test:
  MWL#17: Table elimination:
  - Amend testsuite to provide full gcov coverage
This commit is contained in:
Sergey Petrunya
2009-08-27 01:01:40 +04:00
parent c483437781
commit 005c24e973
3 changed files with 129 additions and 1 deletions
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66
mysql-test/r/table_elim.result
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@ -352,3 +352,69 @@ explain select t1.a from t1 left join t3 on t3.pk1=t1.a and t3.pk2 IS NULL;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4
drop table t1,t2,t3;
#
# Multi-equality tests
#
create table t1 (a int, b int, c int, d int);
insert into t1 values (0,0,0,0),(1,1,1,1),(2,2,2,2),(3,3,3,3);
create table t2 (pk int primary key, b int, c int);
insert into t2 select a,a,a from t1 where a in (1,2);
explain
select t1.*
from t1 left join t2 on t2.pk=t2.c and t2.b=t1.a and t1.a=t1.b and t2.c=t2.b
where t1.d=1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4 Using where
explain
select t1.*
from
t1
left join
t2
on (t2.pk=t2.c and t2.b=t1.a and t1.a=t1.b and t2.c=t2.b) or
(t2.pk=t2.c and t2.b=t1.a and t1.a=t1.b and t2.c=t2.b)
where t1.d=1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4 Using where
#This can't be eliminated:
explain
select t1.*
from
t1
left join
t2
on (t2.pk=t2.c and t2.b=t1.a and t2.c=t1.b) or
(t2.pk=t2.c and t1.a=t1.b and t2.c=t1.b)
where t1.d=1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4 Using where
1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t1.b 1
explain
select t1.*
from
t1
left join
t2
on (t2.pk=t2.c and t2.b=t1.a and t2.c=t1.b) or
(t2.pk=t2.c and t2.c=t1.b)
;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4
explain
select t1.*
from t1 left join t2 on t2.pk=3 or t2.pk= 4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4
1 SIMPLE t2 index PRIMARY PRIMARY 4 NULL 2 Using index
explain
select t1.*
from t1 left join t2 on t2.pk=3 or t2.pk= 3;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4
explain
select t1.*
from t1 left join t2 on (t2.pk=3 and t2.b=3) or (t2.pk= 4 and t2.b=3);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4
1 SIMPLE t2 range PRIMARY PRIMARY 4 NULL 2 Using where
drop table t1, t2;