This patch disables the query cache for the federated engine.

sql/ha_federated.h:
  Fix cache issues

sql/ha_federated.h

@@ -282,6 +282,7 @@ class ha_federated: public handler
              HA_CREATE_INFO *create_info);                      //required
   ha_rows records_in_range(uint inx, key_range *start_key,
                                    key_range *end_key);
+  uint8 table_cache_type() { return HA_CACHE_TBL_NOCACHE; }
 
   THR_LOCK_DATA **store_lock(THD *thd, THR_LOCK_DATA **to,
                              enum thr_lock_type lock_type);     //required