[Devel] [Engine-devel] vds_dynamic refactor

[Gilad Chaplik]

----- Original Message -----
> From: "Liran Zelkha" <liran.zelkha at gmail.com>
> To: "Kobi Ianko" <kobi at redhat.com>
> Cc: "Gilad Chaplik" <gchaplik at redhat.com>, devel at linode01.ovirt.org, "engine-devel" <engine-devel at ovirt.org>
> Sent: Sunday, April 6, 2014 3:40:13 PM
> Subject: Re: [Devel] [Engine-devel] vds_dynamic refactor
> 
> On Sun, Apr 6, 2014 at 3:37 PM, Kobi Ianko <kobi at redhat.com> wrote:
> 
> > Joining in...
> > From my point of view, in real life a user should have that many VDSs on
> > one Engine (from a DB point of view).
> > Modern DB system handles tables with millions of records and many
> > relations, Do we really have a performance issue here?
> > We could prefer a more easy to maintain implantation in this case over DB
> > performance
> >
> > Yes we do. We make many queries on the VDS view, which is a VERY complex
> view.
> 

Actually I quite agree with Kobi, what is the plan for VMs? why do we start with VDS... 
what is the biggest deploy do you know of?

> >
> > ----- Original Message -----
> > > From: "Gilad Chaplik" <gchaplik at redhat.com>
> > > To: "Liran Zelkha" <liran.zelkha at gmail.com>
> > > Cc: devel at linode01.ovirt.org, "engine-devel" <engine-devel at ovirt.org>
> > > Sent: Sunday, April 6, 2014 3:32:26 PM
> > > Subject: Re: [Devel] [Engine-devel] vds_dynamic refactor
> > >
> > > ----- Original Message -----
> > > > From: "Liran Zelkha" <liran.zelkha at gmail.com>
> > > > To: "Gilad Chaplik" <gchaplik at redhat.com>
> > > > Cc: "Itamar Heim" <iheim at redhat.com>, devel at linode01.ovirt.org,
> > > > "engine-devel" <engine-devel at ovirt.org>
> > > > Sent: Sunday, April 6, 2014 3:26:24 PM
> > > > Subject: Re: [Engine-devel] vds_dynamic refactor
> > > >
> > > > On Sun, Apr 6, 2014 at 3:18 PM, Gilad Chaplik <gchaplik at redhat.com>
> > wrote:
> > > >
> > > > > ----- Original Message -----
> > > > > > From: "Itamar Heim" <iheim at redhat.com>
> > > > > > To: "Liran Zelkha" <liran.zelkha at gmail.com>
> > > > > > Cc: "Gilad Chaplik" <gchaplik at redhat.com>,
> > devel at linode01.ovirt.org,
> > > > > "engine-devel" <engine-devel at ovirt.org>
> > > > > > Sent: Sunday, April 6, 2014 11:33:12 AM
> > > > > > Subject: Re: [Engine-devel] vds_dynamic refactor
> > > > > >
> > > > > > On 04/06/2014 11:32 AM, Liran Zelkha wrote:
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > On Sun, Apr 6, 2014 at 11:22 AM, Itamar Heim <iheim at redhat.com
> > > > > > > <mailto:iheim at redhat.com>> wrote:
> > > > > > >
> > > > > > >     On 04/03/2014 07:51 PM, Liran Zelkha wrote:
> > > > > > >
> > > > > > >         The problem is with both updates and selects.
> > > > > > >         For selects - to get all the information for the VDS we
> > have
> > > > > > >         multiple
> > > > > > >         joins. Adding another one will hurt performance even
> > more.
> > > > > > >         For updates - we have vds_static thats hardly changed.
> > > > > > >         vds_statistics
> > > > > > >         that changes all the time. vds_dynamic is not changed
> > allot -
> > > > > but
> > > > > > >         is
> > > > > > >         updated all the time because of the status. I think it's
> > best
> > > > > to
> > > > > > >         split
> > > > > > >         it to the two existing tables (BTW - relevant for VM as
> > well)
> > > > > > >
> > > > > > >
> > > > > > >     but we don't update it unless the status has changed, which
> > is a
> > > > > > >     rare occurance?
> > > > > > >
> > > > > > > Actually - no. We can definitely see times we are updating
> > > > > > > vds_dynamic
> > > > > > > with no reason at all. I tried to create patches for that - but
> > it
> > > > > > > happens from many different places in the code.
> > > > > >
> > > > > > what would be updated vds_dyanmic for status not originating in
> > update
> > > > > > run time info?
> > > > >
> > > > > We have separate DB flows for that (updateStatus and
> > > > > updatePartialVdsDynamicCalc and more in VdsDynamicDAODbFacadeImpl).
> > > > > A question: do you know if we update status in updateVdsDynamic? :-)
> > not
> > > > > sure but I found a possible race for pending resources (cpu, mem),
> > LOL
> > > > > :-)
> > > > >
> > > > > I think we do but not sure. Will check.
> > >
> > > Of course it is, that was a rhetorical question :-) (a lot of emoticons
> > and
> > > LOLs ;-))
> > >
> > > >
> > > >
> > > > > Still holds my original thought for having vds_on_boot.
> > > > >
> > > > >
> > > > >
> > > > Let's talk f2f on Tuesday?
> > >
> > > I'd prefer to reach conclusions here, I'd like everyone to be involved
> > in a
> > > root issue like this one.
> >
> 
> What is the update frequency of this field?
> 

which field?
status? pending resources? on boot fields?
iinm, status is updated mostly by user actions, at least in positive scenarios, and not that often.


> > >
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