On Thu, Jun 28, 2012 at 8:04 AM, Anthony <abasta...@gmail.com> wrote: >> > Anyway, you might be better off looking into using the scheduler, or a >> > third-party task queue like Celery (a web2py Celery plugin was started >> > at >> > some point, though not sure it is complete). >> >> I don't understand, how will that let me do a read-modify-update >> transaction? It seems as if for_update is precisely what I need to do >> that. > > I thought your original goal was to set up a task queue -- those suggestions > are specialized for that purpose.
Yes, it is. The email-queue example in The Book has a caveat that only one server can be used. That's because with more than one server process, the same work item might be processed several times. If I had a read-modify-update transaction, then a server could mark a particular work item as taken/in-progress and it wouldn't matter how many servers I had. It would work with just one, or if I needed to spin up a few more, I could that without introducing errors, race-conditions, etc. Right? -=Doug
