On Wed, 2010-05-05 at 08:08 +0800, Russell Keith-Magee wrote:
> On Wed, May 5, 2010 at 1:43 AM, J. Cliff Dyer <j...@sdf.lonestar.org> wrote:
> > I'm having trouble working with multi-db using mysql replication. When
> > I run our test suite, I'm getting several hundred errors if I have more
> > than one database configured, and none if I have only one configured.
> >
> > It seems that something isn't getting properly cleared out between test
> > cases, so duplicate objects are getting created.
> >
> > My DATABASES setting looks like this:
> >
> >
> > DATABASES = {
> > 'default': {
> > 'ENGINE': 'django.db.backends.mysql',
> > 'HOST': 'jellyroll',
> > 'NAME': 'ee',
> > 'USER': 'ee',
> > 'PASSWORD': 'ee',
> > 'OPTIONS': {
> > 'init_command': 'SET storage_engine=INNODB',
> > 'charset' : 'utf8',
> > 'use_unicode' : True,
> > },
> > },
> > 'replicant0': {
> > 'ENGINE': 'django.db.backends.mysql',
> > 'HOST': 'jellyroll-rep0',
> > 'NAME': 'test',
> > 'USER': 'ee',
> > 'PASSWORD': 'ee',
> > 'TEST_MIRROR': 'default',
> > 'OPTIONS': {
> > 'init_command': 'SET storage_engine=INNODB',
> > 'charset' : 'utf8',
> > 'use_unicode' : True,
> > },
> > },
> > }
> >
> >
> > My router looks like this:
> >
> > class PrimaryReplicantRouter(object):
> > """Set up routing with one primary database, and zero or more
> > replicant databases."""
> >
> > db_list = settings.DATABASES.keys()
> > primary_db = 'default'
> > replicant_db_list = [x for x in db_list if x != primary_db]
> >
> > def db_for_read(self, model, **hints):
> > try:
> > return random.choice(self.replicant_db_list)
> > except IndexError:
> > return self.primary_db
> >
> >
> > def db_for_write(self, model, **hints):
> > """Write to the Primary DB"""
> > return self.primary_db
> >
> > def allow_relation(self, obj1, obj2, **hints):
> > """Allow a relationship between any two objects in the db
> > pool"""
> >
> > if (obj1._state.db in self.db_list
> > and obj2._state.db in self.db_list):
> > return True
> > return None
> >
> > def allow_syncdb(self, db, models):
> > """All writes go to the primary db."""
> > return db == self.primary_db
> >
> > The first error that comes out of the test suite is a duplicate username
> > in auth during a testcase's setUp, which makes it look like the object
> > is getting created on one test pass, and then created again the next
> > time around without deleting it properly:
> >
> >
> > $ ./manage.py test --failfast
> > .....E
> > ======================================================================
> > ERROR: Regressiontest for #12462
> > ----------------------------------------------------------------------
> > Traceback (most recent call last):
> > File
> > "/home/cliff/projects/lr-mdb/lexilereader/web/../contrib/django/contrib/auth/tests/auth_backends.py",
> > line 14, in setUp
> > User.objects.create_user('test', 't...@example.com', 'test')
> > ...
> > IntegrityError: (1062, "Duplicate entry 'test' for key 2")
> >
> >
> > Any ideas what's going wrong?
>
> I can't say I've seen this problem myself. Some more details might
> help narrow down the problem:
>
> * Is your test case marked as a multidb test? (i.e., multidb=True on
> the test case itself)
>
> * Can you describe your database configuration in more detaill?
> Specifically, when the test framework creates the test database
> (presumably on 'jellyroll') does a slave also get created
> automatically? Is the test slave automatically paired to the test
> master?
>
> Yours,
> Russ Magee %-)
>
Thanks, and sorry it took so long for me to revive this. I traced the
problem to a replication error. Somehow, the primary database was
getting created with the InnoDB engine, but the replicants were getting
created with MyISAM.
Cheers,
Cliff
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