Horton

Re: Add LZ4 compression in pg_dump

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: Tomas Vondra <tomas.vondra@enterprisedb.com>, gkokolatos@pm.me, shiy.fnst@fujitsu.com, pgsql-hackers@lists.postgresql.org, Rachel Heaton <rachelmheaton@gmail.com>
Date: 2023-04-13T00:37:06Z
Lists: pgsql-hackers 
On Wed, Apr 12, 2023 at 05:52:40PM -0500, Justin Pryzby wrote:
> I don't think you need to call parse_compress_specification(NONE).
> As you wrote it, if zlib is unavailable, there's no parse(NONE) call,
> even for directory and custom formats.  And there's no parse(NONE) call
> for plan format when zlib is available.

Yeah, that's not necessary, but I was wondering if it made the code a
bit cleaner, or else the non-zlib path would rely on the default
compression method string.

> The old way had preprocessor #if around both the "if" and "else" - is
> that what you meant?
> 
> If you don't insist on calling parse(NONE), the only change is to remove
> the empty #else, which was my original patch.

Removing the empty else has as problem to create an empty if block,
which could be itself a cause of warnings?

> If I were to rewrite the comment, it'd say:
> 
> +        * When gzip is available, custom and directory formats are compressed by
> +        * default

Okay.
--
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,