Horton

Teach pg_receivewal to use lz4 compression

gkokolatos@pm.me

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From: gkokolatos@pm.me
To: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-06-29T14:45:17Z
Lists: pgsql-hackers

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Hi,

The program pg_receivewal can use gzip compression to store the received WAL.
This patch teaches it to be able to use lz4 compression if the binary is build
using the -llz4 flag.

Previously, the user had to use the option --compress with a value between [0-9]
to denote that gzip compression was requested. This specific behaviour is
maintained. A newly introduced option --compress-program=lz4 can be used to ask
for the logs to be compressed using lz4 instead. In that case, no compression
values can be selected as it does not seem too useful.

Under the hood there is nothing exceptional to be noted. Tar based archives have
not yet been taught to use lz4 compression. Those are used by pg_basebackup. If
is is felt useful, then it is easy to be added in a new patch.

Cheers,
//Georgios

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