Question

I have one thread that writes results into a Queue.

In another thread (GUI), I periodically (in the IDLE event) check if there are results in the queue, like this:

def queue_get_all(q):     items = []     while 1:         try:             items.append(q.get_nowait())         except Empty, e:             break     return items 

Is this a good way to do it ?

Edit:

I’m asking because sometimes the waiting thread gets stuck for a few seconds without taking out new results.

The ‘stuck’ problem turned out to be because I was doing the processing in the idle event handler, without making sure that such events are actually generated by calling wx.WakeUpIdle, as is recommended.

Answer 1

I’d be very surprised if the get_nowait() call caused the pause by not returning if the list was empty.

Could it be that you’re posting a large number of (maybe big?) items between checks which means the receiving thread has a large amount of data to pull out of the Queue? You could try limiting the number you retrieve in one batch:

def queue_get_all(q):     items = []     maxItemsToRetrieve = 10     for numOfItemsRetrieved in range(0, maxItemsToRetrieve):         try:             if numOfItemsRetrieved == maxItemsToRetrieve:                 break             items.append(q.get_nowait())         except Empty, e:             break     return items 

This would limit the receiving thread to pulling up to 10 items at a time.