Horton

Re: Different compression methods for FPI

x4mmm@yandex-team.ru

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From: Andrey Borodin <x4mmm@yandex-team.ru>
To: Heikki Linnakangas <hlinnaka@iki.fi>
Cc: Michael Paquier <michael@paquier.xyz>, Justin Pryzby <pryzby@telsasoft.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Thomas Munro <thomas.munro@gmail.com>, Peter Geoghegan <pg@bowt.ie>, Andres Freund <andres@anarazel.de>
Date: 2021-06-16T08:52:50Z
Lists: pgsql-hackers 

> 16 июня 2021 г., в 13:49, Heikki Linnakangas <hlinnaka@iki.fi> написал(а):
> 
> Hmm, do we currently compress each block in a WAL record separately, for records that contain multiple full-page images? That could make a big difference e.g. for GiST index build that WAL-logs 32 pages in each record. If it helps the compression, we should probably start WAL-logging b-tree index build in larger batches, too.

Here's PoC for this [0]. But benchmark results are HW-dependent.

Best regards, Andrey Borodin.

https://www.postgresql.org/message-id/flat/41822E78-48EE-41AE-A89B-3CB76FF53980%40yandex-team.ru

Commits

  1. Add more error context to RestoreBlockImage() and consume it

  2. Add support for LZ4 with compression of full-page writes in WAL

  3. Extended statistics on expressions

  4. Be clear about whether a recovery pause has taken effect.

  5. Add GUC to enable compression of full page images stored in WAL.