Re: track_planning causing performance regression

<https://commitfest.postgresql.org/29/2634/>

On Mon, Jul 6, 2020 at 10:29 AM Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com>
wrote:

>
>
> On 2020/07/04 12:22, Pavel Stehule wrote:
> >
> >
> > pá 3. 7. 2020 v 13:02 odesílatel Fujii Masao <
> masao(dot)fujii(at)oss(dot)nttdata(dot)com <mailto:masao(dot)fujii(at)oss(dot)nttdata(dot)com>> napsal:
> >
> >
> >
> > On 2020/07/03 16:02, Pavel Stehule wrote:
> > >
> > >
> > > pá 3. 7. 2020 v 8:57 odesílatel Fujii Masao <
> masao(dot)fujii(at)oss(dot)nttdata(dot)com <mailto:masao(dot)fujii(at)oss(dot)nttdata(dot)com> <mailto:
> masao(dot)fujii(at)oss(dot)nttdata(dot)com <mailto:masao(dot)fujii(at)oss(dot)nttdata(dot)com>>> napsal:
> > >
> > >
> > >
> > > On 2020/07/03 13:05, Pavel Stehule wrote:
> > > > Hi
> > > >
> > > > pá 3. 7. 2020 v 4:39 odesílatel Fujii Masao <
> masao(dot)fujii(at)oss(dot)nttdata(dot)com <mailto:masao(dot)fujii(at)oss(dot)nttdata(dot)com> <mailto:
> masao(dot)fujii(at)oss(dot)nttdata(dot)com <mailto:masao(dot)fujii(at)oss(dot)nttdata(dot)com>> <mailto:
> masao(dot)fujii(at)oss(dot)nttdata(dot)com <mailto:masao(dot)fujii(at)oss(dot)nttdata(dot)com> <mailto:
> masao(dot)fujii(at)oss(dot)nttdata(dot)com <mailto:masao(dot)fujii(at)oss(dot)nttdata(dot)com>>>>
> napsal:
> > > >
> > > >
> > > >
> > > > On 2020/07/01 7:37, Peter Geoghegan wrote:
> > > > > On Tue, Jun 30, 2020 at 6:40 AM Fujii Masao <
> masao(dot)fujii(at)oss(dot)nttdata(dot)com <mailto:masao(dot)fujii(at)oss(dot)nttdata(dot)com> <mailto:
> masao(dot)fujii(at)oss(dot)nttdata(dot)com <mailto:masao(dot)fujii(at)oss(dot)nttdata(dot)com>> <mailto:
> masao(dot)fujii(at)oss(dot)nttdata(dot)com <mailto:masao(dot)fujii(at)oss(dot)nttdata(dot)com> <mailto:
> masao(dot)fujii(at)oss(dot)nttdata(dot)com <mailto:masao(dot)fujii(at)oss(dot)nttdata(dot)com>>>> wrote:
> > > > >> Ants and Andres suggested to replace the spinlock
> used in pgss_store() with
> > > > >> LWLock. I agreed with them and posted the POC
> patch doing that. But I think
> > > > >> the patch is an item for v14. The patch may
> address the reported performance
> > > > >> issue, but may cause other performance issues in
> other workloads. We would
> > > > >> need to measure how the patch affects the
> performance in various workloads.
> > > > >> It seems too late to do that at this stage of v13.
> Thought?
> > > > >
> > > > > I agree that it's too late for v13.
> > > >
> > > > Thanks for the comment!
> > > >
> > > > So I pushed the patch and changed default of
> track_planning to off.
> > > >
> > > >
> > > > Maybe there can be documented so enabling this option can
> have a negative impact on performance.
> > >
> > > Yes. What about adding either of the followings into the doc?
> > >
> > > Enabling this parameter may incur a noticeable
> performance penalty.
> > >
> > > or
> > >
> > > Enabling this parameter may incur a noticeable
> performance penalty,
> > > especially when a fewer kinds of queries are executed
> on many
> > > concurrent connections.
> > >
> > >
> > > This second variant looks perfect for this case.
> >
> > Ok, so patch attached.
> >
> >
> > +1
>
> Thanks for the review! Pushed.
>
> Regards,
>
> --
> Fujii Masao
> Advanced Computing Technology Center
> Research and Development Headquarters
> NTT DATA CORPORATION
>
>
>
You might also want to update this patch's status in the commitfest:
https://commitfest.postgresql.org/29/2634/

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