Horton

Re: Teach pg_receivewal to use lz4 compression

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Georgios Kokolatos <gkokolatos@pm.me>, Magnus Hagander <magnus@hagander.net>, Dilip Kumar <dilipbalaut@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-02-12T03:52:40Z
Lists: pgsql-hackers 
On Fri, Feb 11, 2022 at 10:07:49AM -0500, Robert Haas wrote:
> Over in http://postgr.es/m/CA+TgmoYUDEJga2qV_XbAZ=pGEBaOsgFmzZ6Ac4_sRwOm_+UeHA@mail.gmail.com
> I was noticing that CreateWalTarMethod doesn't support LZ4
> compression. It would be nice if it did. I thought maybe the patch on
> this thread would fix that, but I think maybe it doesn't, because it
> looks like that's touching the WalDirectoryMethod part of that file,
> rather than the WalTarMethod part. Is that correct?

Correct.  pg_receivewal only cares about the directory method, so this
thread was limited to this part.  Yes, it would be nice to extend
fully the tar method of walmethods.c to support LZ4, but I was not
sure what needed to be done, and I am still not sure based on what has
just been done as of 751b8d23.

> And, on a related note, Michael, do you plan to get something
> committed here? 

Apart from f79962d, babbbb5 and 50e1441, I don't think that there was
something left to do for this thread.  Perhaps I am missing something?
--
Michael

Commits

  1. Fix header inclusion order in pg_receivewal.c

  2. Remove useless LZ4 system call on failure when writing file header

  3. Add support for LZ4 compression in pg_receivewal

  4. Rework compression options of pg_receivewal

  5. Clarify some errors in pg_receivewal when closing WAL segments