if you want transactions you need to do : with transaction.atomic():
like described here: https://docs.djangoproject.com/en/dev/topics/db/transactions/ Am Mittwoch, 22. Mai 2013 10:40:15 UTC+2 schrieb Christian Schmitt: > > In Django the normal behavior should be that when you do a save() it will > automatically commit() your query's to the database. > so that in obj.save() you should just could access the pk with obj.idafter > you did a obj.save(). > If you want to maybe stop the commit you need to do a obj = > obj.save(commit=False), then you could add some things to your obj and > commit/save it later. > But as i understood you already do a obj.save() but it doesn't commit > correctly? Maybe you should just try a PostgreSQL database for testing, > since I'm not having trouble looking up objects after i saved it. > > I often do things like: > obj.save() > return HttpResponseRedirect(reverse('view', {'pk': obj.id})) > and i never run into any exception > > > Am Dienstag, 21. Mai 2013 23:20:53 UTC+2 schrieb Chris Conover: >> >> Calling transaction.commit() after object.save results in >> a TransactionManagementError. I mentioned at the end that I am using MySQL >> (5.5.27). The issue is not that the Gearman workers are having trouble >> saving their transactions, it's that they are having trouble looking up the >> incoming object. I'm assuming the view and workers are separate >> transactions since I don't see how they could be connected -- though I'm >> looking into this. >> >> On Tuesday, May 21, 2013 1:05:54 PM UTC-4, Tom Evans wrote: >>> >>> 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.
