Opened 7 years ago

Closed 7 years ago

Last modified 7 years ago

#28445 closed Bug (invalid)

DateField timezone issue with get_or_create (duplicate key value violates unique constraint)

Reported by: Jure Erznožnik Owned by: nobody
Component: Database layer (models, ORM) Version: 1.10
Severity: Normal Keywords: orm timezone get_or_create
Cc: Triage Stage: Unreviewed
Has patch: no Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: no UI/UX: no


My model:

class AccessUseByDomain(models.Model):
    domain = models.IntegerField(verbose_name=_('Domain'), choices=settings.DOMAINS, null=True, blank=True)
    date = models.DateField(verbose_name=_('Date'), auto_now=True)
    no_access = models.IntegerField(verbose_name=_('Accesses'))

    class Meta:
        unique_together = [
                ['domain', 'date']  # Logic.consume_access

The code that leads to error:

        c, unused = AccessUseByDomain.objects.get_or_create(domain=device.hw_domain,,
        c.no_access += 1

Queries generated in this code block:

  • {'sql': 'SELECT "my_team_accessusebydomain"."id", "my_team_accessusebydomain"."domain", "my_team_accessusebydomain"."date", "my_team_accessusebydomain"."no_access" FROM "my_team_accessusebydomain" WHERE ("my_team_accessusebydomain"."domain" = 0 AND "my_team_accessusebydomain"."date" = \'2017-07-27\'::date)', 'time': '0.001'}
  • {'sql': 'SAVEPOINT "s140667396605696_x4"', 'time': '0.000'}
  • {'sql': 'INSERT INTO "my_team_accessusebydomain" ("domain", "date", "no_access") VALUES (0, \'2017-07-28\'::date, 0) RETURNING "my_team_accessusebydomain"."id"', 'time': '0.003'}
  • {'sql': 'ROLLBACK TO SAVEPOINT "s140667396605696_x4"', 'time': '0.000'}
  • {'sql': 'RELEASE SAVEPOINT "s140667396605696_x4"', 'time': '0.000'}
  • {'sql': 'SELECT "my_team_accessusebydomain"."id", "my_team_accessusebydomain"."domain", "my_team_accessusebydomain"."date", "my_team_accessusebydomain"."no_access" FROM "my_team_accessusebydomain" WHERE ("my_team_accessusebydomain"."domain" = 0 AND "my_team_accessusebydomain"."date" = \'2017-07-27\'::date)', 'time': '0.000'}

(please note the different date generated between selects and insert)

Relevant section:

TIME_ZONE = 'Europe/Ljubljana'
USE_I18N = True
USE_L10N = True
USE_TZ = True

When this happens:
I'm getting this error between midnight and 2am on the server (the code is not client-dependent, I hope). As it happens, the server is in CET timezone, which is +2 right now. Naturally, the code in question has to be run at least twice.

It would seem that either get or create part of the get_or_create does not do appropriate timezone adjustments for the date provided in the filter. My bet is on the get part (the date in INSERT statement is the correct one).

Note: I'm sorry I can't test this on 1.11, as I'm using MultipleChoiceField in forms and haven't figured out a way to replace it yet. The release notes only say those (undocumented classes) were removed, but nothing on what to use instead. I can confirm though that 1.9 exhibits the same behaviour.

Change History (3)

comment:1 by Tim Graham, 7 years ago

Resolution: needsinfo
Status: newclosed

The code looks suspicious. Since the field has auto_now=True, it uses as the creation value, regardless of you provide. I'd suggest replacing with and checking if the issue still happens. Please reopen the ticket if you identify that Django is really at fault.

comment:2 by Jure Erznožnik, 7 years ago

Removing auto_now=True solved the problem.
I still don't see how that IS the solution: I WAS using now() for date in searc / create. auto_now should make o difference.
Thanks for the suggestion.

comment:3 by Tim Graham, 7 years ago

Resolution: needsinfoinvalid

The get() in get_or_create() used while the create() used`. The values might be different.

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