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

From Robert Haas
Subject Re: Use fadvise in wal replay
Date
Msg-id CA+TgmoYNirSJ5cLNzYa-QRfkoGcKJx949DGi=XDSTvvjFXHDbw@mail.gmail.com
Whole thread Raw
In response to RE: Use fadvise in wal replay  (Jakub Wartak <Jakub.Wartak@tomtom.com>)
Responses Re: Use fadvise in wal replay
List pgsql-hackers
On Thu, Jun 23, 2022 at 5:49 AM Jakub Wartak <Jakub.Wartak@tomtom.com> wrote:
> Cool. As for GUC I'm afraid there's going to be resistance of adding yet another GUC (to avoid many knobs). Ideally
itwould be nice if we had some advanced/deep/hidden parameters , but there isn't such thing.
 
> Maybe another option would be to use (N * maintenance_io_concurrency * XLOG_BLCKSZ), so N=1 that's 80kB and N=2 160kB
(prettyclose to default value, and still can be tweaked by enduser). Let's wait what others say?
 

I don't think adding more parameters is a problem intrinsically. A
good question to ask, though, is how the user is supposed to know what
value they should configure. If we don't have any idea what value is
likely to be optimal, odds are users won't either.

It's not very clear to me that we have any kind of agreement on what
the basic approach should be here, though.

-- 
Robert Haas
EDB: http://www.enterprisedb.com



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