Fixed LP bug #900469.

The execution plan cannot use sorting on the first table from the
sequence of the joined tables if it plans to employ the block-based
hash join algorithm.

mysql-test/r/join_cache.result

@@ -5264,4 +5264,53 @@ a
 SET SESSION join_cache_level = DEFAULT;
 SET optimizer_switch=@tmp_optimizer_switch;
 DROP TABLE t1,t2,t3;
+#
+# Bug #900469: semijoin + BNLH + ORDER BY 
+#
+CREATE TABLE t1 (a int, b int);
+INSERT INTO t1 VALUES (8,10);
+CREATE TABLE t2 (c int, d int);
+INSERT INTO t2 VALUES (8,10);
+INSERT INTO t2 VALUES (9,11);
+CREATE TABLE t3 (c int, d int);
+INSERT INTO t3 VALUES (8,10);
+INSERT INTO t3 VALUES (9,11);
+SET @tmp_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch='semijoin_with_cache=on';
+SET join_cache_level=1;
+EXPLAIN
+SELECT * FROM t1,t2 WHERE b IN (SELECT d FROM t3 WHERE c <= t2.c) ORDER BY a,d;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	1	Using temporary; Using filesort
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary; End temporary; Using join buffer (flat, BNL join)
+SELECT * FROM t1,t2 WHERE b IN (SELECT d FROM t3 WHERE c <= t2.c) ORDER BY a,d;
+a	b	c	d
+8	10	8	10
+8	10	9	11
+SET join_cache_level=3;
+EXPLAIN
+SELECT * FROM t1,t2 WHERE b IN (SELECT d FROM t3 WHERE c <= t2.c);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	1	
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	t3	hash_ALL	NULL	#hash#$hj	5	const	2	Using where; Start temporary; End temporary; Using join buffer (flat, BNLH join)
+SELECT * FROM t1,t2 WHERE b IN (SELECT d FROM t3 WHERE c <= t2.c);
+a	b	c	d
+8	10	8	10
+8	10	9	11
+SET join_cache_level=3;
+EXPLAIN
+SELECT * FROM t1,t2 WHERE b IN (SELECT d FROM t3 WHERE c <= t2.c) ORDER BY a,d;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	1	Using temporary; Using filesort
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	t3	hash_ALL	NULL	#hash#$hj	5	const	2	Using where; Start temporary; End temporary; Using join buffer (flat, BNLH join)
+SELECT * FROM t1,t2 WHERE b IN (SELECT d FROM t3 WHERE c <= t2.c) ORDER BY a,d;
+a	b	c	d
+8	10	8	10
+8	10	9	11
+SET SESSION join_cache_level = DEFAULT;
+SET optimizer_switch=@tmp_optimizer_switch;
+DROP TABLE t1,t2,t3;
 set @@optimizer_switch=@save_optimizer_switch;

mysql-test/t/join_cache.test

@@ -3323,5 +3323,43 @@ SET optimizer_switch=@tmp_optimizer_switch;
 
 DROP TABLE t1,t2,t3;
 
+--echo #
+--echo # Bug #900469: semijoin + BNLH + ORDER BY 
+--echo #
+
+CREATE TABLE t1 (a int, b int);
+INSERT INTO t1 VALUES (8,10);
+
+CREATE TABLE t2 (c int, d int);
+INSERT INTO t2 VALUES (8,10);
+INSERT INTO t2 VALUES (9,11);
+
+CREATE TABLE t3 (c int, d int);
+INSERT INTO t3 VALUES (8,10);
+INSERT INTO t3 VALUES (9,11);
+
+SET @tmp_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch='semijoin_with_cache=on';
+
+SET join_cache_level=1;
+EXPLAIN
+SELECT * FROM t1,t2 WHERE b IN (SELECT d FROM t3 WHERE c <= t2.c) ORDER BY a,d;
+SELECT * FROM t1,t2 WHERE b IN (SELECT d FROM t3 WHERE c <= t2.c) ORDER BY a,d;
+
+SET join_cache_level=3;
+EXPLAIN
+SELECT * FROM t1,t2 WHERE b IN (SELECT d FROM t3 WHERE c <= t2.c);
+SELECT * FROM t1,t2 WHERE b IN (SELECT d FROM t3 WHERE c <= t2.c);
+
+SET join_cache_level=3;
+EXPLAIN
+SELECT * FROM t1,t2 WHERE b IN (SELECT d FROM t3 WHERE c <= t2.c) ORDER BY a,d;
+SELECT * FROM t1,t2 WHERE b IN (SELECT d FROM t3 WHERE c <= t2.c) ORDER BY a,d;
+
+SET SESSION join_cache_level = DEFAULT;
+SET optimizer_switch=@tmp_optimizer_switch;
+
+DROP TABLE t1,t2,t3;
+
 # this must be the last command in the file
 set @@optimizer_switch=@save_optimizer_switch;

sql/sql_select.cc

@@ -1448,7 +1448,7 @@ JOIN::optimize()
     order=0;
 
   // Can't use sort on head table if using join buffering
-  if (full_join)
+  if (full_join || hash_join)
   {
     TABLE *stable= (sort_by_table == (TABLE *) 1 ? 
       join_tab[const_tables].table : sort_by_table);
@@ -7036,6 +7036,7 @@ get_best_combination(JOIN *join)
     DBUG_RETURN(TRUE);
 
   join->full_join=0;
+  join->hash_join= FALSE;
 
   used_tables= OUTER_REF_TABLE_BIT;		// Outer row is already read
 
@@ -7125,6 +7126,11 @@ get_best_combination(JOIN *join)
     }
     else if (create_ref_for_key(join, j, keyuse, used_tables))
       DBUG_RETURN(TRUE);                        // Something went wrong
+
+    if ((j->type == JT_REF || j->type == JT_EQ_REF) &&
+        is_hash_join_key_no(j->ref.key))
+      join->hash_join= TRUE; 
+
   loop_end:
     /* 
       Save records_read in JOIN_TAB so that select_describe()/etc don't have

sql/sql_select.h

@@ -912,6 +912,7 @@ class JOIN :public Sql_alloc
   */
   bool     sort_and_group; 
   bool     first_record,full_join, no_field_update;
+  bool     hash_join;
   bool	   do_send_rows;
   /**
     TRUE when we want to resume nested loop iterations when