CMFActivity: Memoize dependant activities when they share the same serialization tag

Otherwise, for each activity, a read is called on activity tables for
each activity sharing the serialization tag

product/CMFActivity/Activity/Queue.py

@@ -136,14 +136,22 @@ class Queue(object):
       return EXCEPTION
     return VALID
 
-  def getDependentMessageList(self, activity_tool, message):
+  def getDependentMessageList(self, activity_tool, message, serialization_cache_dict):
     message_list = []
     for k, v in message.activity_kw.iteritems():
-      message_list += activity_tool.getDependentMessageList(message, k, v)
+      # If dependant message list already found for serialization, then use cache
+      if k == 'serialization_tag':
+        if serialization_cache_dict.get(v):
+          message_list += serialization_cache_dict.get(v)
+        else:
+          serialization_cache_dict[v] = activity_tool.getDependentMessageList(message, k, v)
+          message_list += serialization_cache_dict[v]
+      else:
+        message_list += activity_tool.getDependentMessageList(message, k, v)
     return message_list
 
   def getExecutableMessageList(self, activity_tool, message, message_dict,
-                               validation_text_dict, now_date=None):
+                               validation_text_dict, serialization_cache_dict, now_date=None):
     """Get messages which have no dependent message, and store them in the dictionary.
 
     If the passed message itself is executable, simply store only that message.
@@ -165,7 +173,7 @@ class Queue(object):
 
     cached_result = validation_text_dict.get(message.order_validation_text)
     if cached_result is None:
-      message_list = self.getDependentMessageList(activity_tool, message)
+      message_list = self.getDependentMessageList(activity_tool, message, serialization_cache_dict)
       transaction.commit() # Release locks.
       if message_list:
         # The result is not empty, so this message is not executable.
@@ -180,7 +188,8 @@ class Queue(object):
             message_dict[message.uid] = None
             try:
               self.getExecutableMessageList(activity_tool, m, message_dict,
-                                             validation_text_dict, now_date=now_date)
+                                            validation_text_dict, serialization_cache_dict,
+                                            now_date=now_date)
             finally:
               del message_dict[message.uid]
       else:

product/CMFActivity/Activity/SQLBase.py

@@ -366,11 +366,17 @@ class SQLBase(Queue):
 
       validation_text_dict = {'none': 1}
       message_dict = {}
+      serialization_cache_dict = {}
       for line in result:
         message = Message.load(line.message, uid=line.uid, line=line)
         if not hasattr(message, 'order_validation_text'): # BBB
           message.order_validation_text = self.getOrderValidationText(message)
+        if 'serialization_tag' in message.activity_kw:
+          serialization_cache_dict.setdefault(
+            message.activity_kw['serialization_tag'], []
+          )
         self.getExecutableMessageList(activity_tool, message, message_dict,
+                                      serialization_cache_dict,
                                       validation_text_dict, now_date=now_date)
       if message_dict:
         distributable_uid_set = set()