public inbox for [email protected]
help / color / mirror / Atom feedFrom: Ranier Vilela <[email protected]>
To: lakshmi <[email protected]>
Cc: Bryan Green <[email protected]>
Cc: Pg Hackers <[email protected]>
Subject: Re: Avoid multiple calls to memcpy (src/backend/access/index/genam.c)
Date: Wed, 25 Mar 2026 08:38:55 -0300
Message-ID: <CAEudQArPTeDn5P1hHY9jcfaVqKt81mHCrPKiYRwcA1TjS7nkkg@mail.gmail.com> (raw)
In-Reply-To: <CAEvyyTgcuGXmMoG0bBy85crZ2TROodRoeg=b6jzQxTprGsNm1Q@mail.gmail.com>
References: <CAEudQApbWon+3Eb9x4WW_D-JkSt2mvfx99dXu9VZ4AeCuTh=fw@mail.gmail.com>
<CAEudQApEfvhNT1fEPURzVcQH7G0A1ukh_ugoCGaErV6_dbndCQ@mail.gmail.com>
<CAF+pBj_RS2KErTqQ6ORXjhVzmukG7Ve0wHU1Kq56xjJfFKwVqA@mail.gmail.com>
<CAEudQAptRymgvmd5hQb2mk-Ft89XcSo_xvC74kv4JBA9v=D4Sg@mail.gmail.com>
<CAF+pBj-K2bgNQRc9ih01WFmAWUaQtVbS37jLtYdYh5LOwOkF6A@mail.gmail.com>
<CAF+pBj9M8rCoS-EEBwLiA6hdxm_UNjxMXG9Vc4RU8xifqnQB-g@mail.gmail.com>
<CAEvyyTjLYVuy0V6gXE9_HgyB4gUftuTZm65gdbacE_OOKk1cqw@mail.gmail.com>
<CAEudQAoF2xfpA7tgW3gusg0dyMTwTDDwAzBqR_bbv08NBkqv-A@mail.gmail.com>
<CAEvyyTjT70OVN_NCcHQ+PodVM7bkPccKPzJcAv0u+eW=qpZDMg@mail.gmail.com>
<CAEudQArStWAwxLM6ORNo2YtJ=Uw-MNRv9B-k_gQ6O=yt=7GtAA@mail.gmail.com>
<CAEvyyTgcuGXmMoG0bBy85crZ2TROodRoeg=b6jzQxTprGsNm1Q@mail.gmail.com>
Hi.
Em qua., 25 de mar. de 2026 às 08:26, lakshmi <[email protected]>
escreveu:
>
> Hi,
>>>
>>> Thanks for the suggestion and for the earlier discussion.
>>>
>> Could you repeat the tests without enable-debug?
>>
> I repeated the tests using a non-debug (optimized) build of PostgreSQL
> (19devel), built without --enable-debug.
>
> Test setup:
>
> -
>
> Debian Linux (x86_64)
> -
>
> gcc 12.2.0
> -
>
> AMD Ryzen 5 7535U (6 cores / 12 threads)
> -
>
> pgbench scale factor 1
> -
>
> command: pgbench -p 55432 -d postgres -c 10 -j 4 -T 60 I ran multiple
> iterations for both the original and patched versions and considered the
> stable runs (excluding those affected by checkpoints).
>
> Thanks.
>
> -
>
> Results:
>
> Original:
> TPS: ~1047
> Latency: ~9.5 ms
>
> Patched:
> TPS: ~1040
> Latency: ~9.6 ms
>
> From these runs, the results are quite close, and I didn’t observe a
> consistent performance improvement with the patch under this workload. The
> differences appear to be within normal run-to-run variation.
>
> I agree.
> -
>
> It may be that this change has limited impact in typical cases where
> the number of keys is small. It would be interesting to see how it behaves
> with workloads involving larger numbers of keys or different access
> patterns.
>
> I believe it's unnecessary; I think it's been clearly demonstrated that
there has been no improvement, so it's not worth it.
> -
>
> Please let me know if you’d like me to try any additional scenarios.
>
> Thank you for testing.
For me, the lesson here is that this is the first time I've seen that
unloop doesn't work any better.
best regards,
Ranier Vilela
view thread (17+ messages)
reply
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: [email protected]
Cc: [email protected], [email protected], [email protected]
Subject: Re: Avoid multiple calls to memcpy (src/backend/access/index/genam.c)
In-Reply-To: <CAEudQArPTeDn5P1hHY9jcfaVqKt81mHCrPKiYRwcA1TjS7nkkg@mail.gmail.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox