1 files changed, 39 insertions, 6 deletions

diff --git a/sql/handler.h b/sql/handler.h
index 9863d541b5f..d25796d8546 100644
--- a/sql/handler.h
+++ b/sql/handler.h
@@ -841,16 +841,49 @@ public:
 
   /* Type of table for caching query */
   virtual uint8 table_cache_type() { return HA_CACHE_TBL_NONTRANSACT; }
-  /* ask handler about permission to cache table when query is to be cached */
+
+
+  /**
+    @brief Register a named table with a call back function to the query cache.
+
+    @param thd The thread handle
+    @param table_key A pointer to the table name in the table cache
+    @param key_length The length of the table name
+    @param[out] engine_callback The pointer to the storage engine call back
+      function
+    @param[out] engine_data Storage engine specific data which could be
+      anything
+
+    This method offers the storage engine, the possibility to store a reference
+    to a table name which is going to be used with query cache. 
+    The method is called each time a statement is written to the cache and can
+    be used to verify if a specific statement is cachable. It also offers
+    the possibility to register a generic (but static) call back function which
+    is called each time a statement is matched against the query cache.
+
+    @note If engine_data supplied with this function is different from
+      engine_data supplied with the callback function, and the callback returns
+      FALSE, a table invalidation on the current table will occur.
+
+    @return Upon success the engine_callback will point to the storage engine
+      call back function, if any, and engine_data will point to any storage
+      engine data used in the specific implementation.
+      @retval TRUE Success
+      @retval FALSE The specified table or current statement should not be
+        cached
+  */
+
   virtual my_bool register_query_cache_table(THD *thd, char *table_key,
-					     uint key_length,
-					     qc_engine_callback
-					     *engine_callback,
-					     ulonglong *engine_data)
+                                             uint key_length,
+                                             qc_engine_callback
+                                             *engine_callback,
+                                             ulonglong *engine_data)
   {
     *engine_callback= 0;
-    return 1;
+    return TRUE;
   }
+
+
  /*
   RETURN
     true  Primary key (if there is one) is clustered key covering all fields