Re: Different compression methods for FPI

From: Michael Paquier <michael(at)paquier(dot)xyz>
To: Andrey Borodin <x4mmm(at)yandex-team(dot)ru>
Cc: Justin Pryzby <pryzby(at)telsasoft(dot)com>, Peter Eisentraut <peter(dot)eisentraut(at)enterprisedb(dot)com>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Thomas Munro <thomas(dot)munro(at)gmail(dot)com>, Peter Geoghegan <pg(at)bowt(dot)ie>, Andres Freund <andres(at)anarazel(dot)de>
Subject: Re: Different compression methods for FPI
Date: 2021-06-29 03:41:43
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On Tue, Jun 22, 2021 at 09:11:26AM +0900, Michael Paquier wrote:
> What about the following error then? Say:
> "image at %X/%X compressed with LZ4 not supported by build, block
> %d".
>> Also, maybe %s can be inlined to lz4 in this case.
> I think that's a remnant of the zstd part of the patch set, where I
> wanted to have only one translatable message. Sure, I can align lz4
> with the message.
>> 2.
>> > const char *method = "???";
>> Maybe we can use something like "unknown" for unknown compression
>> methods? Or is it too long string for waldump output?
> A couple of extra bytes for pg_waldump will not matter much. Using
> "unknown" is fine by me.

I have kept 1. as-is for translability, and included 2.

Now that v15 is open for business, I have looked again at this stuff
this morning and committed the LZ4 part after some adjustments:
- Avoid the use of default in the switches used for the compression,
so as the compiler would warn when introducing a new value in the enum
used for wal_compression.
- Switched to LZ4_compress_default(). LZ4_compress_fast() could be
used with LZ4_ACCELERATION_DEFAULT, but toast_compression.c uses the

I got check-world tested with wal_compression = {lz4,pglz,off}, and
did some manuals checks, including some stuff without --with-lz4.
Attached is the rest of the patch set for zstd, for reference, rebased
with the changes that have been committed. This still requires proper
support in the MSVC scripts.

My buildfarm machine has been changed to use wal_compression = lz4,
while on it for HEAD runs.

Attachment Content-Type Size
v12-0001-Add-wal_compression-zstd.patch text/x-diff 20.0 KB

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