check_join_cache_usage() by the change:

Revno: 2793
Revision Id: igor@askmonty.org-20091221022615-kx5ieiu0okmiupuc
Timestamp: Sun 2009-12-20 18:26:15 -0800

Backport into MariaDB-5.2 the following:
WL#2771 "Block Nested Loop Join and Batched Key Access Join"