Merge fix for BUG#787299.

mysql-test/r/subselect_sj.result

@@ -1245,4 +1245,25 @@ t1field
 2
 3
 drop table t1,t2;
+# 
+# BUG#787299: Valgrind complains on a join query with two IN subqueries
+#
+create table t1 (a int);
+insert into t1 values (1), (2), (3);
+create table t2 as select * from t1;
+select * from t1 A, t1 B
+where A.a = B.a and A.a in (select a from t2 C) and B.a in (select a from t2 D);
+a	a
+1	1
+2	2
+3	3
+explain
+select * from t1 A, t1 B
+where A.a = B.a and A.a in (select a from t2 C) and B.a in (select a from t2 D);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	3	Start temporary
+1	PRIMARY	B	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer (flat, BNL join)
+1	PRIMARY	C	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer (flat, BNL join)
+1	PRIMARY	D	ALL	NULL	NULL	NULL	NULL	3	Using where; End temporary; Using join buffer (flat, BNL join)
+drop table t1, t2;
 set @@optimizer_switch=@save_optimizer_switch;

mysql-test/r/subselect_sj_jcl6.result

@@ -1253,6 +1253,27 @@ t1field
 2
 3
 drop table t1,t2;
+# 
+# BUG#787299: Valgrind complains on a join query with two IN subqueries
+#
+create table t1 (a int);
+insert into t1 values (1), (2), (3);
+create table t2 as select * from t1;
+select * from t1 A, t1 B
+where A.a = B.a and A.a in (select a from t2 C) and B.a in (select a from t2 D);
+a	a
+1	1
+2	2
+3	3
+explain
+select * from t1 A, t1 B
+where A.a = B.a and A.a in (select a from t2 C) and B.a in (select a from t2 D);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	3	Start temporary
+1	PRIMARY	B	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer (flat, BNL join)
+1	PRIMARY	C	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer (incremental, BNL join)
+1	PRIMARY	D	ALL	NULL	NULL	NULL	NULL	3	Using where; End temporary; Using join buffer (incremental, BNL join)
+drop table t1, t2;
 set @@optimizer_switch=@save_optimizer_switch;
 #
 # BUG#49129: Wrong result with IN-subquery with join_cache_level=6 and firstmatch=off

mysql-test/t/subselect_sj.test

@@ -1137,5 +1137,18 @@ WHERE
                 WHERE C.t2field IN (SELECT D.t2field FROM t2 D));
 drop table t1,t2;
 
+--echo # 
+--echo # BUG#787299: Valgrind complains on a join query with two IN subqueries
+--echo #
+create table t1 (a int);
+insert into t1 values (1), (2), (3);
+create table t2 as select * from t1;
+select * from t1 A, t1 B
+ where A.a = B.a and A.a in (select a from t2 C) and B.a in (select a from t2 D);
+explain
+select * from t1 A, t1 B
+ where A.a = B.a and A.a in (select a from t2 C) and B.a in (select a from t2 D);
+drop table t1, t2;
+
 # The following command must be the last one the file 
 set @@optimizer_switch=@save_optimizer_switch;

sql/opt_subselect.cc

@@ -2042,7 +2042,7 @@ void advance_sj_state(JOIN *join, table_map remaining_tables,
   /* Initialize the state or copy it from prev. tables */
   if (idx == join->const_tables)
   {
-    pos->first_firstmatch_table= MAX_TABLES;
+    pos->invalidate_firstmatch_prefix();
     pos->first_loosescan_table= MAX_TABLES; 
     pos->dupsweedout_tables= 0;
     pos->sjm_scan_need_tables= 0;
@@ -2107,7 +2107,7 @@ void advance_sj_state(JOIN *join, table_map remaining_tables,
       pos->first_firstmatch_rtbl= remaining_tables;
     }
 
-    if (pos->first_firstmatch_table != MAX_TABLES)
+    if (pos->in_firstmatch_prefix())
     {
       if (outer_corr_tables & pos->first_firstmatch_rtbl)
       {
@@ -2115,7 +2115,7 @@ void advance_sj_state(JOIN *join, table_map remaining_tables,
           Trying to add an sj-inner table whose sj-nest has an outer correlated 
           table that was not in the prefix. This means FirstMatch can't be used.
         */
-        pos->first_firstmatch_table= MAX_TABLES;
+        pos->invalidate_firstmatch_prefix();
       }
       else
       {
@@ -2123,7 +2123,8 @@ void advance_sj_state(JOIN *join, table_map remaining_tables,
         pos->firstmatch_need_tables|= sj_inner_tables;
       }
     
-      if (!(pos->firstmatch_need_tables & remaining_tables))
+      if (pos->in_firstmatch_prefix() && 
+          !(pos->firstmatch_need_tables & remaining_tables))
       {
         /*
           Got a complete FirstMatch range.

sql/sql_select.h

@@ -584,6 +584,8 @@ typedef struct st_position
    */
   table_map firstmatch_need_tables;
 
+  bool in_firstmatch_prefix() { return (first_firstmatch_table != MAX_TABLES); }
+  void invalidate_firstmatch_prefix() { first_firstmatch_table= MAX_TABLES; }
 
 /* Duplicate Weedout strategy */
   /* The first table that the strategy will need to handle */