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: Tom Lane <tgl@sss.pgh.pa.us>, Michael Paquier <michael@paquier.xyz>
Cc: gkokolatos@pm.me, 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: 2023-05-08T18:00:39Z
Lists: pgsql-hackers

Attachments

On 5/8/23 03:16, Tom Lane wrote:
> I wrote:
>> Michael Paquier <michael@paquier.xyz> writes:
>>> While testing this patch, I have triggered an error pointing out that
>>> the decompression path of LZ4 is broken for table data.  I can
>>> reproduce that with a dump of the regression database, as of:
>>> make installcheck
>>> pg_dump --format=d --file=dump_lz4 --compress=lz4 regression
> 
>> Ugh.  Reproduced here ... so we need an open item for this.
> 
> BTW, it seems to work with --format=c.
> 

The LZ4Stream_write() forgot to move the pointer to the next chunk, so
it was happily decompressing the initial chunk over and over. A bit
embarrassing oversight :-(

The custom format calls WriteDataToArchiveLZ4(), which was correct.

The attached patch fixes this for me.


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,