Horton

Re: .ready and .done files considered harmful

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Stephen Frost <sfrost@snowman.net>
Cc: Dilip Kumar <dilipbalaut@gmail.com>, Andres Freund <andres@anarazel.de>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2021-05-05T20:00:56Z
Lists: pgsql-hackers 
On Wed, May 5, 2021 at 1:06 PM Stephen Frost <sfrost@snowman.net> wrote:
> It's not just about making sure that we archive the history file for a
> timeline before archiving WAL segments along that timeline but also
> about making sure we get that history file into the archive as fast as
> we can, and archiving a 16MB WAL first would certainly delay that.

Ooph. That's a rather tough constraint. Could we get around it by
introducing some kind of signalling mechanism, perhaps? Like if
there's a new history file, that must mean the server has switched
timelines -- I think, anyway -- so if we notified the archiver every
time there was a timeline switch it could react accordingly.

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

Commits

  1. Reduce overhead of renaming archive status files.

  2. Improve performance of pgarch_readyXlog() with many status files.

  3. Prioritize history files when archiving