Fixed LP bug #794909.

The function generate_derived_keys did not take into account the fact
that the last element in the array of keyuses could be just a barrier
element. In some cases it could lead to a crash of the server.

Also fixed a couple of other bugs in generate_derived_keys: the inner 
loop in the body of if this function did not change the cycle variables
properly.

1 files changed, 21 insertions, 0 deletions

diff --git a/mysql-test/r/derived_view.result b/mysql-test/r/derived_view.result
index 5125f91005f..5e3fc1e8cf1 100644
--- a/mysql-test/r/derived_view.result
+++ b/mysql-test/r/derived_view.result
@@ -568,3 +568,24 @@ TODO: Add test with 64 tables mergeable view to test fall back to
 materialization on tables > MAX_TABLES merge
 drop table t1,t2;
 drop view v1,v2,v3,v4,v6,v7;
+#
+#  LP bug #794909: crash when defining possible keys for
+#                  a materialized view/derived_table
+#
+CREATE TABLE t1 (f1 int) ;
+INSERT INTO t1 VALUES (149), (150), (224), (29);
+CREATE TABLE t2 (f1 int, KEY (f1));
+INSERT INTO t2 VALUES (149), (NULL), (224);
+CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT * FROM t1;
+EXPLAIN
+SELECT * FROM v1 JOIN t2 ON v1.f1 = t2.f1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	index	f1	f1	5	NULL	3	Using where; Using index
+1	PRIMARY	<derived2>	ref	key0	key0	5	test.t2.f1	2	
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	4	
+SELECT * FROM v1 JOIN t2 ON v1.f1 = t2.f1;
+f1	f1
+149	149
+224	224
+DROP VIEW v1;
+DROP TABLE t1,t2;