Excerpts from Adam Young's message of 2013-07-08 13:18:55 -0700: > On 07/01/2013 01:35 PM, Clint Byrum wrote: > > The way the new keystone-manage command "token_flush" works right now > > is quite broken by MySQL and InnoDB's gap locking behavior: > > > > https://bugs.launchpad.net/1188378 > > > > Presumably other SQL databases like PostgreSQL will have similar problems > > with doing massive deletes, but I am less familiar with them. > > > > I am trying to solve this in keystone, and my first attempt is here: > > > > https://review.openstack.org/#/c/32044/ > > > > However, MySQL does not support using "LIMIT" in a sub-query that > > is feeding an IN() clause, so that approach will not work. Likewise, > > sqlalchemy does not support the MySQL specific extension to DELETE which > > allows it to have a LIMIT clause. > > > > Now, I can do some hacky things, like just deleting all of the expired > > tokens from the oldest single second, but that could also potentially > > be millions of tokens, and thus, millions of gaps to lock. > > > > So, there is just not one way to work for all databases, and we have to > > have a special mode for MySQL. > > > > I was wondering if anybody has suggestions and/or examples of how to do > > that with sqlalchemy. > > > > _______________________________________________ > > OpenStack-dev mailing list > > OpenStack-dev@lists.openstack.org > > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > In general, if you have millions of roles, you need a real database. I > would not try to work through SQL Alchemy for this. Instead, you > probably just want to make sure that the token_flush is run fairly > regularly on your database. >
I'm not sure I understand you. * I am asking about millions of tokens, not roles. * I am asking about MySQL.. presumably a "real" database. * In the bug, I am suggesting that running token_flush once every second will be _a disaster_ on a busy site with MySQL because of the gap locking behavior in InnoDB. We need to delete a small number per transaction. _______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
