Open Stack

On 09/09/13 13:12, Roman Podolyaka wrote:
> Hi,
> 
> I'm ok with both accepting this patch and reverting the commit, which
> introduced the regression, but it would be really nice to have these DB
> optimizations in Nova.
> 
> As for your concern of accepting such optimizations. I don't think, it's
> a problem of such patches themselves, but rather with the lack of
> comprehensive tests of complex OpenStack installations in our CI (at the
> same time I personally believe our CI is the best thing ever happened to
> OpenStack :), CI team you really rock!).
> 

More CI is always good - and OpenStack CI is amazing without a doubt.
However - I think this is not something that ties in very much with
these kind of optimisations.

The problem with (most) optimisations is that they optimise for a use
case. No matter how at scale you tested this - it is still one data
point - and this patch does not come for free (regression risk,
technical debt to name only a few). You can mitigate some of the issues
with CI - but you can't say for sure that this is not in fact slower for
people with different deployments/usage patterns.

Now this patch may very well be a net win - but I personally have no way
of knowing that - and to me - this is the problem with this whole
approach - I see the downsides, but don't see the conclusive evidence of
the pros of it (we tried it on a really big (tm) cluster - it must be
better is not real data IMHO).

I realize that we as a project are approaching the point where
performance is a thing we need to care about - but then we need to own
it as a project (maybe have a sub-team that works on this exclusively).
One shot DB query optimisations in Python code seem like a horrible
anti-pattern TBH.

I may propose a session on this for the summit.

Cheers,

N.

> Anyway, TripleO-CI found this regression. Maybe we should consider
> adding its job to Nova check/gate pipelines?
> 
> Thanks,
> Roman
> 
> 
> On Mon, Sep 9, 2013 at 1:59 PM, Nikola Đipanov <ndipanov at redhat.com
> <mailto:ndipanov at redhat.com>> wrote:
> 
>     On 09/09/13 11:25, Roman Podolyaka wrote:
>     > Hi,
>     >
>     > There is a patch on review (https://review.openstack.org/#/c/45422/)
>     > fixing https://bugs.launchpad.net/tripleo/+bug/1221620 which has
>     > importance 'Critical' in Nova and TripleO (long story short: currently
>     > Nova Baremetal deployments with more than one baremetal node won't
>     work).
>     >
>     > It would be really nice to have this patch reviewed by core
>     developers,
>     > so we can fix the bug ASAP.
>     >
> 
>     Hey - thanks for responding quickly - I commented on the patch and tbh I
>     am starting to be -1 on this due to issues mentioned on the review.
> 
>     I will accept that my take on this is too conservative :) and remove a
>     -1 if needed to get this in, but at this point, I have some doubts
>     weather this is the right approach.
> 
>     Cheers,
> 
>     N.
> 
> 
>     > Thanks,
>     > Roman
>     >
>     >
>     > _______________________________________________
>     > OpenStack-dev mailing list
>     > OpenStack-dev at lists.openstack.org
>     <mailto: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
>     <mailto: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
>