On Tue, May 21, 2013 at 4:23 PM, Chris Conover <[email protected]> wrote: > Hello, > > I'm having an issue looking up objects immediately after they are saved and > am wondering if anyone has any advice on how to address the problem. > Specifically, I'm saving an object in a view (nothing fancy, a simple > save()) and then kicking off a Gearman task to do some operations on that > saved object in the background. I pass the newly created object's PK as data > to the Gearman worker which then does a simple Objects.objects.get(pk=PK). > However, almost all of the time this lookup operation fails with an > DoesNotExist exception. I believe the problem has to do with transactions. > Namely, the read in the Gearman worker is happening before the write from > the view is committed to the database. I've tried several things including > refactoring the saving code to be wrapped in a > @transaction.commit_on_success block, moving the worker submission to > post_save and adding a long delay before the Gearman worker does the lookup. > Nothing really seems to solve the problem completely. Even with a 60 second > delay, the lookup fails with some frequency. Am I missing something here? Is > there some Django query cache that I can clear? Or should I just rewrite all > this to just to use a look-back perspective. > > The stack is Django 1.4 connecting to MySQL 5.5.27. Django is handling > 200-1000 requests per second and the database is handling about double that. > > Thanks, > Chris
from django import transaction … obj.save() transaction.commit() task.submit(obj.id) You will also need to make sure that gearman is doing things correctly as well. You haven't mentioned what database you are using, but if gearman's DB connection is in a read repeated mode, you can do whatever you like in django but you won't see new data in gearman until gearman's current transaction is committed. Cheers Tom -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/django-users?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
