Horton

Re: Add LZ4 compression in pg_dump

Michael Paquier <michael@paquier.xyz>

View thread View on postgr.es
From: Michael Paquier <michael@paquier.xyz>
To: gkokolatos@pm.me
Cc: Tomas Vondra <tomas.vondra@enterprisedb.com>, Tom Lane <tgl@sss.pgh.pa.us>, Andrew Dunstan <andrew@dunslane.net>, Alexander Lakhin <exclusion@gmail.com>, Justin Pryzby <pryzby@telsasoft.com>, shiy.fnst@fujitsu.com, pgsql-hackers@lists.postgresql.org, Rachel Heaton <rachelmheaton@gmail.com>
Date: 2023-05-10T02:22:10Z
Lists: pgsql-hackers 
On Tue, May 09, 2023 at 02:12:44PM +0000, gkokolatos@pm.me wrote:
> Thank you both for looking. A small consolation is that now there are
> tests for this case.

+1, noticing that was pure luck ;)

Worth noting that the patch posted in [1] has these tests, not the
version posted in [2].

+    create_sql   => 'INSERT INTO dump_test.test_compression_method (col1) '
+      . 'SELECT string_agg(a::text, \'\') FROM generate_series(1,4096) a;',

Yep, good and cheap idea to check for longer chunks.  That should be
enough to loop twice.

[1]: https://www.postgresql.org/message-id/SYTRcNgtAbzyn3y3IInh1x-UfNTKMNpnFvI3mr6SyqyVf3PkaDsMy_cpKKgsl3_HdLy2MFAH4zwjxDmFfiLO8rWtSiJWBtqT06OMjeNo4GA=@pm.me
[2]: https://www.postgresql.org/message-id/f735df01-0bb4-2fbc-1297-73a520cfc534@enterprisedb.com

> Moving on to the other open item for this, please find attached v2
> of the patch as requested.

Did you notice the comments of [3] about the second patch that aims to
add the null termination in the line from the LZ4 fgets() callback?

[3]: https://www.postgresql.org/message-id/ZFhCyn4Gm2eu60rB@paquier.xyz
--
Michael

Commits

  1. Advance input pointer when LZ4 compressing data

  2. Null-terminate the output buffer of LZ4Stream_gets

  3. Rework code defining default compression for dir/custom formats in pg_dump

  4. pg_dump: Use only LZ4 frame format for compression

  5. Minor comment improvements for compress_lz4

  6. Unify buffer sizes in pg_dump compression API

  7. Improve type handling in pg_dump's compress file API

  8. Improve wording in pg_dump compression docs

  9. Fix condition in pg_dump TAP test

  10. Add LZ4 compression to pg_dump

  11. Introduce a generic pg_dump compression API

  12. Prepare pg_dump internals for additional compression methods

  13. Fix behavior with pg_restore -l and compressed dumps

  14. Add 250c8ee07ed to git-blame-ignore-revs

  15. Provide test coverage in pg_dump for default behaviors with compression

  16. Switch pg_dump to use compression specifications

  17. Refactor code parsing compression option values (-Z/--compress)

  18. meson: Add some missing env settings for tests of pg_dump and pg_verifybackup

  19. Extend TAP tests of pg_dump to test for compression with gzip

  20. Clean up some dead code in pg_dump with tar format and gzip compression

  21. Add TAP test in pg_dump with --format=tar and --compress

  22. Replace BASE_BACKUP COMPRESSION_LEVEL option with COMPRESSION_DETAIL.

  23. Refactor the pg_dump zlib code from pg_backup_custom.c to a separate file,