Bug #28476: force index on a disabled myisam index gives error 124

When processing the USE/FORCE index hints
the optimizer was not checking if the indexes 
specified are enabled (see ALTER TABLE).
Fixed by:
 Backporting the fix for bug 20604 to 5.0

1 files changed, 16 insertions, 0 deletions

diff --git a/mysql-test/t/myisam.test b/mysql-test/t/myisam.test
index 82d10059c65..12b9423be21 100644
--- a/mysql-test/t/myisam.test
+++ b/mysql-test/t/myisam.test
@@ -1145,4 +1145,20 @@ create table t3 (c1 int) engine=myisam pack_keys=default;
 create table t4 (c1 int) engine=myisam pack_keys=2;
 drop table t1, t2, t3;
 
+#
+# Bug#28476: force index on a disabled myisam index gives error 124
+#
+CREATE TABLE t1(a INT, b INT, KEY inx (a), UNIQUE KEY uinx (b)) ENGINE=MyISAM;
+INSERT INTO t1(a,b) VALUES (1,1),(2,2),(3,3),(4,4),(5,5);
+SELECT a FROM t1 FORCE INDEX (inx) WHERE a=1;
+ALTER TABLE t1 DISABLE KEYS;
+SELECT a FROM t1 FORCE INDEX (inx) WHERE a=1;
+SELECT a FROM t1 USE INDEX (inx) WHERE a=1;
+SELECT b FROM t1 FORCE INDEX (uinx) WHERE b=1;
+SELECT b FROM t1 USE INDEX (uinx) WHERE b=1;
+SELECT a FROM t1 FORCE INDEX (inx,uinx) WHERE a=1;
+ALTER TABLE t1 ENABLE KEYS;
+SELECT a FROM t1 FORCE INDEX (inx) WHERE a=1;
+DROP TABLE t1;
+
 --echo End of 5.0 tests