Poll poll lines and adding them to python queue for processing dies

I have a piece of multithreaded code - 3 threads that poll data from SQS and add it to a python queue. 5, which take messages from the python queue, process them and send them to the system at the back.

Here is the code:

python_queue = Queue.Queue()

class GetDataFromSQS(threading.Thread):
    """Threaded Url Grab"""
    def __init__(self, python_queue):
        threading.Thread.__init__(self)
        self.python_queue = python_queue

    def run(self):
        while True:
            time.sleep(0.5) //sleep for a few secs before querying again
            try:
                msgs = sqs_queue.get_messages(10)
                if msgs == None:
                    print "sqs is empty now"!
                for msg in msgs:
                    #place each message block from sqs into python queue for processing
                    self.python_queue.put(msg)
                    print "Adding a new message to Queue. Queue size is now %d" % self.python_queue.qsize()
                    #delete from sqs
                    sqs_queue.delete_message(msg)
            except Exception as e:
                print "Exception in GetDataFromSQS :: " +  e


class ProcessSQSMsgs(threading.Thread):
    def __init__(self, python_queue):
        threading.Thread.__init__(self)
        self.python_queue = python_queue
        self.pool_manager = PoolManager(num_pools=6)

    def run(self):
        while True:
            #grabs the message to be parsed from sqs queue
            python_queue_msg = self.python_queue.get()
            try:
                processMsgAndSendToBackend(python_queue_msg, self.pool_manager)
            except Exception as e:
                print "Error parsing:: " + e
            finally:
                self.python_queue.task_done()

def processMsgAndSendToBackend(msg, pool_manager):
    if msg != "":
        ###### All the code related to processing the msg
        for individualValue in processedMsg:
            try:
                response = pool_manager.urlopen('POST', backend_endpoint, body=individualValue)
                if response == None:
                    print "Error"
                else:
                    response.release_conn()
            except Exception as e:
                print "Exception! Post data to backend: " + e


def startMyPython():
    #spawn a pool of threads, and pass them queue instance
    for i in range(3):
        sqsThread = GetDataFromSQS(python_queue)
        sqsThread.start()

    for j in range(5):
        parseThread = ProcessSQSMsgs(python_queue)
        #parseThread.setDaemon(True)
        parseThread.start()

    #wait on the queue until everything has been processed
    python_queue.join()
    # python_queue.close() -- should i do this?

startMyPython()

      

        
        
        
      

    

Problem: 3 python employees die randomly (monitored using top -p -H) every few days and it's okay if I kill the process and run the script again. I suspect the workers that disappeared are 3 GetDataFromSQS threads. And since GetDataFromSQS dies, the other 5 workers, although they are working, are always sleeping as there is no data in the python queue. I'm not sure what I am doing wrong here, as I am fairly new to python and am following this tutorial to create this logic and queue threads - http://www.ibm.com/developerworks/aix/library/au-threadingpython/

Thanks in advance for your help. I hope I have explained my problem clearly.