SMP, GIL and Threads

[catsup]

Yes.  Iterating over a list that you concurrently update will
definately cause problems.  That is not the type of "read" I am doing
in the application.  My read is one key/value translation.  Below is an
example of the operations I am performing to help clarify.

The update thread, running once every fifteen minutes, gathers updates
for the dictionary and applies them:

   def run_thread(self):
      while( not self.terminate ):
         sleep(900)
         for agentRec in self.agentListUpdates:
            agentInfo = agentRec[1]
            if agentRec[0] == 'a':
               self.agentByIVRSeq[agentInfo.IVRSeq] = agentInfo  #->
thread hangs here

The accessing thread takes command requests off a queue, every
half-second, placed there by an altogether different thread, and does a
lookup on this same dictionary  before performing this command:

   def run_thread(self):
      while( not self.terminate ):
         cmd = self.cmdQueue.get(False)
         agentInfo = self.agentByIVRSeq[cmd[0]]
         self.performCmd(cmd,agentInfo)
         sleep(.5)