Someone might have already said this (sure wish the listserv sent me mail faster), but we tried out PyMysql and it was exceptionally slow, even under almost no load.
I have a branch in my github that I was using to test out unblocking the database access. For my cases I found that it was unblocked but that it didn't really help performance as much as I had hoped. branch: https://github.com/markwash/nova/tree/optional-db-api-thread-no-pool just the relevant commit: https://github.com/markwash/nova/commit/99e38d3df579670808711eb8acd1f96806d8b6f0 "Vishvananda Ishaya" <vishvana...@gmail.com> said: > Yes it does. We actually tried to use a pool at diablo release and it was > very > broken. There was discussion about moving over to a pure-python mysql > library, but > it hasn't been tried yet. > > Vish > > On Mar 1, 2012, at 11:45 AM, Yun Mao wrote: > >> There are plenty eventlet discussion recently but I'll stick my >> question to this thread, although it's pretty much a separate >> question. :) >> >> How is MySQL access handled in eventlet? Presumably it's external C >> library so it's not going to be monkey patched. Does that make every >> db access call a blocking call? Thanks, >> >> Yun >> >> On Wed, Feb 29, 2012 at 9:18 PM, Johannes Erdfelt <johan...@erdfelt.com> >> wrote: >>> On Wed, Feb 29, 2012, Yun Mao <yun...@gmail.com> wrote: >>>> Thanks for the explanation. Let me see if I understand this. >>>> >>>> 1. Eventlet will never have this problem if there is only 1 OS thread >>>> -- let's call it main thread. >>> >>> In fact, that's exactly what Python calls it :) >>> >>>> 2. In Nova, there is only 1 OS thread unless you use xenapi and/or the >>>> virt/firewall driver. >>>> 3. The python logging module uses locks. Because of the monkey patch, >>>> those locks are actually eventlet or "green" locks and may trigger a >>>> green thread context switch. >>>> >>>> Based on 1-3, does it make sense to say that in the other OS threads >>>> (i.e. not main thread), if logging (plus other pure python library >>>> code involving locking) is never used, and we do not run a eventlet >>>> hub at all, we should never see this problem? >>> >>> That should be correct. I'd have to double check all of the monkey >>> patching that eventlet does to make sure there aren't other cases where >>> you may inadvertently use eventlet primitives across real threads. >>> >>> JE >>> >>> >>> _______________________________________________ >>> Mailing list: https://launchpad.net/~openstack >>> Post to : openstack@lists.launchpad.net >>> Unsubscribe : https://launchpad.net/~openstack >>> More help : https://help.launchpad.net/ListHelp >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~openstack >> Post to : openstack@lists.launchpad.net >> Unsubscribe : https://launchpad.net/~openstack >> More help : https://help.launchpad.net/ListHelp > > > _______________________________________________ > Mailing list: https://launchpad.net/~openstack > Post to : openstack@lists.launchpad.net > Unsubscribe : https://launchpad.net/~openstack > More help : https://help.launchpad.net/ListHelp > _______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : openstack@lists.launchpad.net Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp
