MWL#17: Table elimination:

- 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

1 files changed, 66 insertions, 0 deletions

diff --git a/mysql-test/r/table_elim.result b/mysql-test/r/table_elim.result
index 6d5a540fa04..ae117af3e32 100644
--- a/mysql-test/r/table_elim.result
+++ b/mysql-test/r/table_elim.result
@@ -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;