Horton

Re: Add LZ4 compression in pg_dump

Tomas Vondra <tomas.vondra@enterprisedb.com>

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From: Tomas Vondra <tomas.vondra@enterprisedb.com>
To: Michael Paquier <michael@paquier.xyz>, Justin Pryzby <pryzby@telsasoft.com>
Cc: gkokolatos@pm.me, shiy.fnst@fujitsu.com, pgsql-hackers@lists.postgresql.org, Rachel Heaton <rachelmheaton@gmail.com>
Date: 2023-03-01T14:33:00Z
Lists: pgsql-hackers 
On 3/1/23 08:24, Michael Paquier wrote:
> On Tue, Feb 28, 2023 at 05:58:34PM -0600, Justin Pryzby wrote:
>> I found that e9960732a broke writing of empty gzip-compressed data,
>> specifically LOs.  pg_dump succeeds, but then the restore fails:
> 
> The number of issues you have been reporting here begins to worries
> me..  How many of them have you found?  Is it right to assume that all
> of them have basically 03d02f5 as oldest origin point?

AFAICS a lot of the issues are more a discussion about wording in a
couple places, whether it's nicer to do A or B, name the functions
differently or what.

I'm aware of three genuine issues that I intend to fix shortly:

1) incorrect "if" condition in a TAP test

2) failure when compressing empty LO (which we had no test for)

3) change in handling "compression level = 0" (which I believe should be
made to behave like before)


regards

-- 
Tomas Vondra
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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,