add caching for objectids

master/buildbot/db/state.py

@@ -43,6 +43,17 @@ def getObjectId(self, name, class_name):
         @param class_name: object class name
         @returns: the objectid, via a Deferred.
         """
+        # defer to a cached metho that only takes one parameter (a tuple)
+        return self._getObjectId((name, class_name)
+                ).addCallback(lambda list : list[0])
+
+    @base.cached('objectids')
+    def _getObjectId(self, name_class_name_tuple):
+        """
+        Cache-compatible implementation of L{_getObjectId}, taking a single
+        parameter and returning a weakref-able value (a list).
+        """
+        name, class_name = name_class_name_tuple
         def thd(conn):
             objects_tbl = self.db.model.objects
 
@@ -67,18 +78,18 @@ def insert():
             # then try selecting again.  We include an invocation of a hook
             # method to allow tests to exercise this particular behavior
             try:
-                return select()
+                return [ select() ]
             except _IdNotFoundError:
                 pass
 
             self._test_timing_hook(conn)
 
             try:
-                return insert()
+                return [ insert() ]
             except (sqlalchemy.exc.IntegrityError, sqlalchemy.exc.ProgrammingError):
                 pass
 
-            return select()
+            return [ select() ]
 
         return self.db.pool.do(thd)
 

master/docs/cfg-global.texinfo

@@ -326,6 +326,13 @@ be similar to the number BuildRequesets.
 The number of rows from the @code{sourcestamps} table to cache in memory.  This
 value should be similar to the value for @code{SourceStamps}.
 
+@item objectids
+
+The number of object IDs - a means to correlate an object in the Buildbot
+configuration with an identity in the database - to cache.  In this version,
+object IDs are not looked up often during runtime, so a relatively low value
+such as 10 is fine.
+
 @end enumerate
 
 The @emph{global} @code{buildCacheSize} parameter gives the number of builds