Open Stack

On Fri, Mar 21, 2014 at 5:13 PM, Joe Gordon <joe.gordon0 at gmail.com> wrote:

>
>
>
> On Fri, Mar 21, 2014 at 8:58 AM, Doug Hellmann <
> doug.hellmann at dreamhost.com> wrote:
>
>>
>>
>>
>> On Fri, Mar 21, 2014 at 7:04 AM, Sean Dague <sean at 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.kornienko at gmail.com <mailto:alexei.kornienko at 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?
>

I'll ask him to join #openstack-dev if he is.

Doug



>
>
>>
>> Doug
>>
>>
>>
>>>
>>>         -Sean
>>>
>>> --
>>> Sean Dague
>>> Samsung Research America
>>> sean at dague.net / sean.dague at samsung.com
>>> http://dague.net
>>>
>>>
>>> _______________________________________________
>>> OpenStack-dev mailing list
>>> OpenStack-dev at lists.openstack.org
>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>>>
>>>
>>
>> _______________________________________________
>> OpenStack-dev mailing list
>> OpenStack-dev at lists.openstack.org
>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>>
>>
>
> _______________________________________________
> OpenStack-dev mailing list
> OpenStack-dev at lists.openstack.org
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstack.org/pipermail/openstack-dev/attachments/20140321/9967ca93/attachment.html>