1 files changed, 47 insertions, 0 deletions
diff --git a/mysql-test/t/null_key.test b/mysql-test/t/null_key.test
index d7f6a634d1e..e15aec01d2a 100644
--- a/mysql-test/t/null_key.test
+++ b/mysql-test/t/null_key.test
@@ -193,3 +193,50 @@ select * from t1 where id2 is null or id2 > 0;
 delete from t1 where id <=> NULL;
 select * from t1;
 drop table t1;
+
+#
+# Test for bug #12144: optimizations for key access with null keys 
+#                      used for outer joins
+#
+
+CREATE TABLE t1 (a int);
+CREATE TABLE t2 (a int, b int, INDEX idx(a));
+CREATE TABLE t3 (b int, INDEX idx(b));
+CREATE TABLE t4 (b int, INDEX idx(b));
+INSERT INTO t1 VALUES (1), (2), (3), (4);
+INSERT INTO t2 VALUES (1, 1), (3, 1);
+INSERT INTO t3 VALUES 
+  (NULL), (NULL), (NULL), (NULL), (NULL),
+  (NULL), (NULL), (NULL), (NULL), (NULL);
+INSERT INTO t4 SELECT * FROM t3;
+INSERT INTO t3 SELECT * FROM t4;
+INSERT INTO t4 SELECT * FROM t3;
+INSERT INTO t3 SELECT * FROM t4;
+INSERT INTO t4 SELECT * FROM t3;
+INSERT INTO t3 SELECT * FROM t4;
+INSERT INTO t4 SELECT * FROM t3;
+INSERT INTO t3 SELECT * FROM t4;
+INSERT INTO t4 SELECT * FROM t3;
+INSERT INTO t3 SELECT * FROM t4;
+INSERT INTO t4 SELECT * FROM t3;
+INSERT INTO t3 SELECT * FROM t4;
+INSERT INTO t4 SELECT * FROM t3;
+INSERT INTO t3 SELECT * FROM t4;
+INSERT INTO t4 SELECT * FROM t3;
+INSERT INTO t3 SELECT * FROM t4;
+INSERT INTO t3 VALUES (2), (3);
+
+ANALYZE table t1, t2, t3;
+
+SELECT COUNT(*) FROM t3;
+
+EXPLAIN SELECT SQL_CALC_FOUND_ROWS * FROM t1 LEFT JOIN t2 ON t1.a=t2.a
+                                             LEFT JOIN t3 ON t2.b=t3.b;
+FLUSH STATUS ;
+SELECT SQL_CALC_FOUND_ROWS * FROM t1 LEFT JOIN t2 ON t1.a=t2.a
+                                     LEFT JOIN t3 ON t2.b=t3.b;
+SELECT FOUND_ROWS();
+SHOW STATUS LIKE "handler_read%";
+
+DROP TABLE t1,t2,t3,t4;
+# End of 4.1 tests