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: 2022-12-20T15:26:10Z
Lists: pgsql-hackers 
On Tue, Dec 20, 2022 at 11:19:15AM +0000, gkokolatos@pm.me wrote:
> ------- Original Message -------
> On Monday, December 19th, 2022 at 6:27 PM, Justin Pryzby <pryzby@telsasoft.com> wrote:
> > 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 ?
> 
> Thank you. To be very honest, I am not using github exclusively to post patches.
> Sometimes I do, sometimes I do not. Is github a requirement?

Github isn't a requirement for postgres (but cirrusci only supports
github).  I wasn't not trying to say that it's required, only trying to
make sure that you (and others) know that it's available, since our
cirrus.yml is relatively new.

> > > > > 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
> > 
> 
> Thank you. Now I understand what you mean. Trying the same on top of v18-0003
> on Ubuntu 22.04 yields:

You're right; this seems to be fixed in v18.  Thanks.

It looks like I'd forgotten to run "meson test tmp_install", so had
retested v17...

-- 
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,