BUG#912513: Wrong result (missing rows) with join_cache_hashed+materialization+semijoin=on

- equality substitution code was geared towards processing WHERE/ON clauses.
  that is, it assumed that it was doing substitions on the code that 
   = wasn't attached to any particular join_tab yet
   = was going to be fed to make_join_select() which would take the condition
     apart and attach various parts of it to tables inside/outside semi-joins.
- However, somebody added equality substition for ref access. That is, if 
  we have a ref access on TBL.key=expr, they would do equality substition in
  'expr'. This possibility wasn't accounted for.
- Fixed equality substition code by adding a mode that does equality 
  substition under assumption that the processed expression will be 
  attached to a certain particular table TBL.

1 files changed, 29 insertions, 0 deletions

diff --git a/mysql-test/r/subselect_sj_jcl6.result b/mysql-test/r/subselect_sj_jcl6.result
index 21a8ea39457..faa4140d375 100644
--- a/mysql-test/r/subselect_sj_jcl6.result
+++ b/mysql-test/r/subselect_sj_jcl6.result
@@ -2264,6 +2264,35 @@ w	5	19:11:10
 set optimizer_switch=@save_optimizer_switch;
 set join_cache_level=default;
 DROP TABLE t1,t2,t3;
+#
+# BUG#912513: Wrong result (missing rows) with join_cache_hashed+materialization+semijoin=on
+#
+set @os_912513= @@optimizer_switch;
+set @jcl_912513= @@join_cache_level;
+SET optimizer_switch = 'semijoin=on,materialization=on,join_cache_hashed=on';
+SET join_cache_level = 3;
+CREATE TABLE t1 ( a INT, b INT, KEY(a) );
+INSERT INTO t1 VALUES
+(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7);
+CREATE TABLE t2 ( c INT );
+INSERT INTO t2 VALUES (1),(2),(3),(4),(5),(6),(7);
+SELECT alias1.* FROM
+t1 AS alias1 INNER JOIN t1 AS alias2
+ON alias2.a = alias1.b
+WHERE alias1.b IN (
+SELECT a FROM t1, t2
+);
+a	b
+1	1
+2	2
+3	3
+4	4
+5	5
+6	6
+7	7
+DROP table t1, t2;
+set @@optimizer_switch= @os_912513;
+set @@join_cache_level= @jcl_912513;
 # End
 set join_cache_level=default;
 show variables like 'join_cache_level';