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Date: Tue, 27 Jun 2023 09:42:05 -0500
From: "Tristan Partin" <tristan@neon.tech>
Cc: <pgsql-hackers@postgresql.org>
Subject: Re: Make pgbench exit on SIGINT more reliably
To: "Michael Paquier" <michael@paquier.xyz>, "Yugo NAGATA"
 <nagata@sraoss.co.jp>
Message-Id: <CTNIFM58WEJ3.KY27ZGKO92J7@gonk>
References: <CSSWBAX56CVY.291H6ZNNHK7EO@c3po> <ZG1a5lsSXXiYVJQ6@paquier.xyz>
 <CSUK7YEFYAFZ.3P26BKFUDTO06@c3po>
 <20230619223937.209ff5c4c295da2fbb4adaa0@sraoss.co.jp>
 <CTH123B82H6F.34NSTLQ0XE4AN@gonk>
 <20230622145814.0bbb4b8503eb5147e55ef05a@sraoss.co.jp>
 <ZJTW6dFL9687uzp9@paquier.xyz>
In-Reply-To: <ZJTW6dFL9687uzp9@paquier.xyz>
Archived-At: <https://www.postgresql.org/message-id/CTNIFM58WEJ3.KY27ZGKO92J7%40gonk>
Precedence: bulk

On Thu Jun 22, 2023 at 6:19 PM CDT, Michael Paquier wrote:
> On Thu, Jun 22, 2023 at 02:58:14PM +0900, Yugo NAGATA wrote:
> > On Mon, 19 Jun 2023 16:49:05 -0700
> > "Tristan Partin" <tristan@neon.tech> wrote:
> >> On Mon Jun 19, 2023 at 6:39 AM PDT, Yugo NAGATA wrote:
> >>> [1] https://www.postgresql.org/message-id/flat/CSTU5P82ONZ1.19XFUGHMX=
HBRY%40c3po
> >>=20
> >> The other patch does not replace this one. They are entirely separate.
> >=20
> > After applying the other patch, CancelRequested would be checked enough=
 frequently
> > even during initialization of pgbench_branches and pgbench_tellers, and=
 it will
> > allow the initialization step to be cancelled immediately even if the s=
cale factor
> > is high. So, is it unnecessary to modify setup_cancel_handler anyway?
> >=20
> > I think it would be still nice to introduce a new exit code for query c=
ancel separately.
>
> I have the same impression as Nagata-san while going again through
> the proposal of this thread.  COPY is more responsive to
> interruptions, and is always going to have a much better performance=20
> than individual or multi-value INSERTs for the bulk-loading of data,
> so we could just move on with what's proposed on the other thread and
> solve the problem of this thread on top of improving the loading
> performance.
>
> What are the benefits we gain with the proposal of this thread once we
> switch to COPY as method for the client-side data generation?  If
> the argument is to be able switch to a different error code on
> cancellations for pgbench, that sounds a bit thin to me versus the
> argument of keeping the cancellation callback path as simple as
> possible.

I would say there probably isn't much benefit if you think the polling
for CancelRequested is fine. Looking at the other patch, I think it
might be simple to add an exit code for SIGINT. But I think it might be
best to do it after that patch is merged. I added the other patch to the
commitfest for July. Holding off on this one.

--=20
Tristan Partin
Neon (https://neon.tech)