digoal
2023-04-06
PostgreSQL , PolarDB , pg_dump , compress , none , gzip , lz4 , zstd
pg_dump目前支持的压缩算法包括: gzip, lz4, zstd, 或者不压缩(none)
pg_dump: Add support for zstd compression
author Tomas Vondra <tomas.vondra@postgresql.org>
Wed, 5 Apr 2023 19:38:04 +0000 (21:38 +0200)
committer Tomas Vondra <tomas.vondra@postgresql.org>
Wed, 5 Apr 2023 19:39:33 +0000 (21:39 +0200)
commit 84adc8e20f54e93a003cd316fa1eb9b03e393288
tree aae55866ab14cb7cda70c7d482e04b215efb0596 tree
parent 794f25944790ed0462cde3d6dc0f1ad02fcd6bba commit | diff
pg_dump: Add support for zstd compression
Allow pg_dump to use the zstd compression, in addition to gzip/lz4. Bulk
of the new compression method is implemented in compress_zstd.{c,h},
covering the pg_dump compression APIs. The rest of the patch adds test
and makes various places aware of the new compression method.
The zstd library (which this patch relies on) supports multithreaded
compression since version 1.5. We however disallow that feature for now,
as it might interfere with parallel backups on platforms that rely on
threads (e.g. Windows). This can be improved / relaxed in the future.
This also fixes a minor issue in InitDiscoverCompressFileHandle(), which
was not updated to check if the file already has the .lz4 extension.
Adding zstd compression was originally proposed in 2020 (see the second
thread), but then was reworked to use the new compression API introduced
in e9960732a9. I've considered both threads when compiling the list of
reviewers.
Author: Justin Pryzby
Reviewed-by: Tomas Vondra, Jacob Champion, Andreas Karlsson
Discussion: https://postgr.es/m/20230224191840.GD1653@telsasoft.com
Discussion: https://postgr.es/m/20201221194924.GI30237@telsasoft.com
+ as though it had been fed through <application>gzip</application>,
+ <application>lz4</application>, or <application>zstd</application>;
+ but the default is not to compress.
+ can be compressed with the <application>gzip</application>,
+ <application>lz4</application>, or
+ <application>zstd</application> tools.
<literal>none</literal> for no compression
