On Fri, Mar 21, 2014 at 8:58 AM, Doug Hellmann <doug.hellm...@dreamhost.com>wrote:
> > > > On Fri, Mar 21, 2014 at 7:04 AM, Sean Dague <s...@dague.net> wrote: > >> On 03/20/2014 06:18 PM, Joe Gordon wrote: >> > >> > >> > >> > On Thu, Mar 20, 2014 at 3:03 PM, Alexei Kornienko >> > <alexei.kornie...@gmail.com <mailto:alexei.kornie...@gmail.com>> wrote: >> > >> > Hello, >> > >> > We've done some profiling and results are quite interesting: >> > during 1,5 hour ceilometer inserted 59755 events (59755 calls to >> > record_metering_data) >> > this calls resulted in total 2591573 SQL queries. >> > >> > And the most interesting part is that 291569 queries were ROLLBACK >> > queries. >> > We do around 5 rollbacks to record a single event! >> > >> > I guess it means that MySQL backend is currently totally unusable in >> > production environment. >> > >> > >> > It should be noticed that SQLAlchemy is horrible for performance, in >> > nova we usually see sqlalchemy overheads of well over 10x (time >> > nova.db.api call vs the time MySQL measures when slow log is recording >> > everything). >> >> That's not really a fair assessment. Python object inflation takes time. >> I do get that there is SQLA overhead here, but even if you trimmed it >> out you would not get the the mysql query time. >> >> That being said, having Ceilometer's write path be highly tuned and not >> use SQLA (and written for every back end natively) is probably >> appropriate. >> > > I have been working to get Mike Bayer (author of SQLAlchemy) to the summit > in Atlanta. He is interested in working with us to improve SQLAlchemy, so > if we have specific performance or feature issues like this, it would be > good to make a list. If we have enough, maybe we can set aside a session in > the Oslo track, otherwise we can at least have some hallway conversations. > That would be really amazing. Is he on IRC, so we can get the ball rolling? > > Doug > > > >> >> -Sean >> >> -- >> Sean Dague >> Samsung Research America >> s...@dague.net / sean.da...@samsung.com >> http://dague.net >> >> >> _______________________________________________ >> OpenStack-dev mailing list >> OpenStack-dev@lists.openstack.org >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >> >> > > _______________________________________________ > OpenStack-dev mailing list > OpenStack-dev@lists.openstack.org > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > >
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