From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Petr Jelinek <petr@2ndquadrant.com>
Cc: Andres Freund <andres@anarazel.de>
Cc: Andrey Borodin <x4mmm@yandex-team.ru>
Cc: Konstantin Knizhnik <k.knizhnik@postgrespro.ru>
Cc: Michael Paquier <michael@paquier.xyz>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Cc: Vladimir Leskov <vladimirlesk@yandex-team.ru>
Subject: Re: pglz performance
Date: Sun, 4 Aug 2019 19:30:04 +0200
Message-ID: <20190804173004.ovg6tsf336teyy57@development> (raw)
In-Reply-To: <a5cbd707-e4a4-70e7-e970-75f1cc68c20f@2ndquadrant.com>
References: <DBB2A9E5-29FD-40BF-AC60-BD990FBF142F@yandex-team.ru>
<20190802163948.i6mjypdgujeorrbi@alap3.anarazel.de>
<20190802170039.o4pabnzm4xy3z7uj@development>
<20190802171258.nob5zo2vu7siqo2b@alap3.anarazel.de>
<20190802175239.5ds6rhdso6hwy4vk@development>
<20190802182003.u477q6itwudieqxf@alap3.anarazel.de>
<20190802194859.qxzxq2achzottkup@development>
<d8576096-76ba-487d-515b-44fdedba8bb5@2ndquadrant.com>
<20190804115237.nliwf6hhaqfd62ps@development>
<a5cbd707-e4a4-70e7-e970-75f1cc68c20f@2ndquadrant.com>
On Sun, Aug 04, 2019 at 05:53:26PM +0200, Petr Jelinek wrote:
>
> ...
>
>>
>>4) I did a simple test with physical replication, with lz4 enabled on
>>both sides (well, can't build without lz4 anyway, per previous point).
>>It immediately failed like this:
>>
>>FATAL: failed to restore block image
>>CONTEXT: WAL redo at 0/5000A40 for Btree/INSERT_LEAF: off 138
>>LOG: startup process (PID 15937) exited with exit code 1
>>
>>This is a simple UPDATE on a trivial table:
>>
>>create table t (a int primary key);
>>insert into t select i from generate_series(1,1000) s(i);
>>update t set a = a - 100000 where random () < 0.1;
>>
>>with some checkpoints to force FPW (and wal_compression=on, of course).
>>
>>I haven't tried `make check-world` but I suppose some of the TAP tests
>>should fail because of this. And if not, we need to improve coverage.
>>
>
>FWIW I did run check-world without problems, will have to look into this.
>
Not sure if we bother to set wal_compression=on for check-world (I don't
think we do, but I may be missing something), so maybe check-world does
not really test wal compression.
IMO the issue is that RestoreBlockImage() still calls pglz_decompress
directly, instead of going through pg_decompress().
regards
--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-hackers@postgresql.org
Cc: tomas.vondra@2ndquadrant.com, petr@2ndquadrant.com, andres@anarazel.de, x4mmm@yandex-team.ru, k.knizhnik@postgrespro.ru, michael@paquier.xyz, vladimirlesk@yandex-team.ru
Subject: Re: pglz performance
In-Reply-To: <20190804173004.ovg6tsf336teyy57@development>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox