Re: Proposal: Filter irrelevant change before reassemble transactions during logical decoding

From: Ajin Cherian <itsajin(at)gmail(dot)com>
To: Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
Cc: Peter Smith <smithpb2250(at)gmail(dot)com>, "Hayato Kuroda (Fujitsu)" <kuroda(dot)hayato(at)fujitsu(dot)com>, vignesh C <vignesh21(at)gmail(dot)com>, "Zhijie Hou (Fujitsu)" <houzj(dot)fnst(at)fujitsu(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: Proposal: Filter irrelevant change before reassemble transactions during logical decoding
Date: 2025-06-06 11:44:44
Message-ID: CAFPTHDbZTK1tOY4M29S-PWk=cadB=NRgFSmyjfizHkdyRrG2jA@mail.gmail.com
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On Wed, Jun 4, 2025 at 8:22 PM Ajin Cherian <itsajin(at)gmail(dot)com> wrote:
>
> On Tue, Jun 3, 2025 at 4:25 PM Ajin Cherian <itsajin(at)gmail(dot)com> wrote:
> >
> > On Tue, Jun 3, 2025 at 3:55 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > >
> > >
> > > You haven't shared the exact test scenario, but I am assuming the
> > > above tests are for very large transactions, as you are comparing
> > > streaming and non-streaming modes. Can we see results with short
> > > transaction size (say one insert or one update, or one delete) as
> > > well?
> > >
> >
> > Attaching the scripts I used for my tests. Yes, I used transactions
> > with large inserts. I will redo the tests with short single inserts
> > and share the results here.
>
> I redid the tests with 10k small transactions (single inserts) and the
> results are not great with the patch:

I did some more tests with 20k and 30k transactions. Results attached.

20k Small Transactions

No transactions published: +13.9% improvement
Half transactions published: +0.9% improvement
All transactions published: +1.4% improvement

30k Small Transactions

No transactions published: +15.9% improvement
Half transactions published: −1.3% degradation
All transactions published: +1.3% improvement

regards,
Ajin Cherian
Fujitsu Australia

Attachment Content-Type Size
2k-3k small txns.JPG image/jpeg 98.3 KB

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