Re: Use fadvise in wal replay - Mailing list pgsql-hackers

From Pavel Borisov
Subject Re: Use fadvise in wal replay
Date
Msg-id CALT9ZEGvS2umu65qUJsLd=J7Hx9EpSuQYwQC3O-YUYMUf2nmFA@mail.gmail.com
Whole thread Raw
In response to Re: Use fadvise in wal replay  (Andrey Borodin <amborodin86@gmail.com>)
Responses Re: Use fadvise in wal replay
Re: Use fadvise in wal replay
List pgsql-hackers
Hi, hackers!

On Sun, 13 Nov 2022 at 02:02, Andrey Borodin <amborodin86@gmail.com> wrote:
>
> On Sun, Aug 7, 2022 at 9:41 AM Andrey Borodin <x4mmm@yandex-team.ru> wrote:
> >
>
> Hi everyone. The patch is 16 lines, looks harmless and with proven
> benefits. I'm moving this into RfC.

As I've written up in the thread we can not gain much from this
optimization. The results of Jakub shows around 2% difference:

>baseline, master, default Linux readahead (128kb):
>33.979, 0.478
>35.137, 0.504
>34.649, 0.518>

>master+patched, readahead disabled:
>34.338, 0.528
>34.568, 0.575
>34.007, 1.136

>master+patched, readahead enabled (as default):
>33.935, 0.523
>34.109, 0.501
>33.408, 0.557

On the other hand, the patch indeed is tiny and I don't think the
proposed advise can ever make things bad. So, I've looked through the
patch again and I agree it can be committed in the current state.

Kind regards,
Pavel Borisov,
Supabase



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