Horton

Re: Add LZ4 compression in pg_dump

Justin Pryzby <pryzby@telsasoft.com>

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From: Justin Pryzby <pryzby@telsasoft.com>
To: gkokolatos@pm.me
Cc: Michael Paquier <michael@paquier.xyz>, pgsql-hackers@lists.postgresql.org, Rachel Heaton <rachelmheaton@gmail.com>
Date: 2022-12-19T17:27:06Z
Lists: pgsql-hackers 
On Mon, Dec 19, 2022 at 05:03:21PM +0000, gkokolatos@pm.me wrote:
> > > 001 still doesn't compile on freebsd, and 002 doesn't compile on
> > > windows. Have you checked test results from cirrusci on your private
> > > github account ?
> 
> There are still known gaps in 0002 and 0003, for example documentation,
> and I have not been focusing too much on those. You are right, it is helpful
> and kind to try to reduce the noise. The attached should have hopefully
> tackled the ci errors.

Yep.  Are you using cirrusci under your github account ?

> > FYI, I have re-added an entry to the CF app to get some automated
> > coverage:
> > https://commitfest.postgresql.org/41/3571/
> 
> Much obliged. Should I change the state to "ready for review" when post a
> new version or should I leave that to the senior personnel?   

It's better to update it to reflect what you think its current status
is.  If you think it's ready for review.

> > > 002 breaks "pg_dump -Fc -Z2" because (I think) AllocateCompressor()
> > > doesn't store the passed-in compression_spec.
> 
> I am afraid I have not been able to reproduce this error. I tried both
> debian and freebsd after I addressed the compilation warnings. Which
> error did you get? Is it still present in the attached?

It's not that there's an error - it's that compression isn't working.

$ ./tmp_install/usr/local/pgsql/bin/pg_dump -h /tmp -Z1 -Fp regression |wc -c
659956
$ ./tmp_install/usr/local/pgsql/bin/pg_dump -h /tmp -Z2 -Fp regression |wc -c
637192

$ ./tmp_install/usr/local/pgsql/bin/pg_dump -h /tmp -Z1 -Fc regression |wc -c
1954890
$ ./tmp_install/usr/local/pgsql/bin/pg_dump -h /tmp -Z2 -Fc regression |wc -c
1954890

-- 
Justin

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,