I'll admit my MySQL skills are a bit rusty, but can you examine the database logs to confirm that the session is in fact doing the INSERT and a commit before the SELECT?
On May 28, 2013, at 10:52, Chris Conover <[email protected]> wrote: > It's not really feasible to move this project to PostgreSQL. > > I honestly just don't understand the problem. According to the Django > documentation, the ORM functions in autocommit mode by default. In other > words, the changes should be committed as soon as the query is complete, > right? So after an INSERT, you should be able to do a SELECT and the data > should be available. In the code written, the SELECT is definitely coming > after the INSERT. The code is not complex. I'm setting up a local test to > simulate the load on the production system to see if I can reproduce the > issue. > > On Tuesday, May 28, 2013 1:33:10 PM UTC-4, Christophe Pettus wrote: >> >> In the meantime, you can use this: >> >> https://github.com/Xof/xact >> >> On May 28, 2013, at 10:29, Chris Conover <[email protected]> wrote: >> >>> That seems to only be available in the dev version of Django (now 1.6 >>> alpha). >>> >>> On Wednesday, May 22, 2013 4:43:29 AM UTC-4, Christian Schmitt wrote: >>>> >>>> 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.id >>>>> after 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. > > -- > 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. > > -- You received this message because you are subscribed to the Google Groups "Django users" group. 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