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On Wed, Jul 15, 2015 at 4:51 PM, Matt Fischer <matt at mattfischer.com> wrote:

> I'm having some issues with keystone revocation events. The bottom line is
> that due to the way keystone handles the clean-up of these events[1],
> having more than a few leads to:
>
>  - bad performance, up to 2x slower token validation with about 600 events
> based on my perf measurements.
>  - database deadlocks, which cause API calls to fail, more likely with
> more events it seems
>
> I am seeing this behavior in code from trunk on June 11 using Fernet
> tokens, but the token backend does not seem to make a difference.
>
> Here's what happens to the db in terms of deadlock:
> 2015-07-15 21:25:41.082 31800 TRACE keystone.common.wsgi DBDeadlock:
> (OperationalError) (1213, 'Deadlock found when trying to get lock; try
> restarting transaction') 'DELETE FROM revocation_event WHERE
> revocation_event.revoked_at < %s' (datetime.datetime(2015, 7, 15, 18, 55,
> 41, 55186),)
>
> When this starts happening, I just go truncate the table, but this is not
> ideal. If [1] is really true then the design is not great, it sounds like
> keystone is doing a revocation event clean-up on every token validation
> call. Reading and deleting/locking from my db cluster is not something I
> want to do on every validate call.
>

Unfortunately, that's *exactly* what keystone is doing. Adam and I had a
conversation about this problem in Vancouver which directly resulted in
opening the bug referenced on the operator list:

  https://bugs.launchpad.net/keystone/+bug/1456797

Neither of us remembered the actual implemented behavior, which is what
you've run into and Deepti verified in the bug's comments.


>
> So, can I turn of token revocation for now? I didn't see an obvious no-op
> driver.
>

Not sure how, other than writing your own no-op driver, or perhaps an
extended driver that doesn't try to clean the table on every read?


> And in the long-run can this be fixed? I'd rather do almost anything else,
> including writing a cronjob than what happens now.
>

If anyone has a better solution than the current one, that's also better
than requiring a cron job on something like keystone-manage
revocation_flush I'd love to hear it.


> [1] -
> http://lists.openstack.org/pipermail/openstack-operators/2015-June/007210.html
>
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