From: | Magnus Hagander <magnus(at)hagander(dot)net> |
---|---|
To: | Julien Rouhaud <rjuju123(at)gmail(dot)com> |
Cc: | Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com>, Michael Paquier <michael(at)paquier(dot)xyz>, Andres Freund <andres(at)anarazel(dot)de>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>, Stephen Frost <sfrost(at)snowman(dot)net>, Bruce Momjian <bruce(at)momjian(dot)us>, Christoph Berg <myon(at)debian(dot)org>, Peter Eisentraut <peter(dot)eisentraut(at)enterprisedb(dot)com>, PostgreSQL Developers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
Subject: | Re: compute_query_id and pg_stat_statements |
Date: | 2021-05-11 08:59:51 |
Message-ID: | CABUevEy7pFmw4NeEjpjGhAOKrOaTDVqdw3Z9KshvFKPG=iy3kA@mail.gmail.com |
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On Tue, May 11, 2021 at 10:51 AM Julien Rouhaud <rjuju123(at)gmail(dot)com> wrote:
>
> On Tue, May 11, 2021 at 05:41:53PM +0900, Fujii Masao wrote:
> >
> > On 2021/05/11 16:35, Julien Rouhaud wrote:
> > > Anyway, PFA a patch that implement a [off | on | auto] compute_query_id, and
> > > provides a new queryIdWanted() function to let third party plugins inform us
> > > that they want a query id if possible.
> >
> > Thanks!
> >
> >
> > > As it was noted somewhere in that thread, that's a hack on top on the GUC
> > > machinery, so compute_query_id will display "on" rather than "auto" (or "auto
> > > and enabled" or whatever) since GUC isn't designed to handle that behavior.
> >
> > Can't we work around this issue by making queryIdWanted() set another flag like query_id_wanted instead of overwriting compute_query_id? If we do this, query id computation is necessary when "compute_query_id == COMPUTE_QUERY_ID_ON || (compute_query_id == COMPUTE_QUERY_ID_AUTO && query_id_wanted)".
>
> That's exactly what Magnus mentioned :) It's not possible because variable
> aren't inherited on Windows or EXEC_BACKEND. I didn't check but I'm
> assuming that it could work if the other flag was an internal GUC that couldn't
> be set by users, but then we would have some kind of internal flag that would
> have to be documented as "how to check if compute_query_id" is actually enabled
> or not, which doesn't seem like a good idea.
That doesn't fundamentally make it impossible, you just have to add it
to the list of variables being copied over, wouldn't you? See
save_backend_variables()
--
Magnus Hagander
Me: https://www.hagander.net/
Work: https://www.redpill-linpro.com/
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