Horton

Re: refactoring basebackup.c (zstd workers)

Justin Pryzby <pryzby@telsasoft.com>

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From: Justin Pryzby <pryzby@telsasoft.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Dipesh Pandit <dipesh.pandit@gmail.com>, Andres Freund <andres@anarazel.de>, Jeevan Ladhe <jeevanladhe.os@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, "Shinoda, Noriyoshi (PN Japan FSIP)" <noriyoshi.shinoda@hpe.com>, Abhijit Menon-Sen <ams@toroid.org>, Dmitry Dolgov <9erthalion6@gmail.com>, Jeevan Ladhe <jeevan.ladhe@enterprisedb.com>, Mark Dilger <mark.dilger@enterprisedb.com>, pgsql-hackers@postgresql.org, tushar <tushar.ahuja@enterprisedb.com>
Date: 2022-03-20T19:40:50Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Document BaseBackupSync and BaseBackupWrite wait events.

  2. Support long distance matching for zstd compression

  3. Fix possible NULL-pointer-deference in backup_compression.c.

  4. Allow parallel zstd compression when taking a base backup.

  5. Make PostgreSQL::Test::Cluster::run_log() return a useful value.

  6. Fix a few goofs in new backup compression code.

  7. Replace BASE_BACKUP COMPRESSION_LEVEL option with COMPRESSION_DETAIL.

  8. Add 'basebackup_to_shell' contrib module.

  9. Allow extensions to add new backup targets.

  10. Change HAVE_LIBLZ4 and HAVE_LIBZSTD tests to USE_LZ4 and USE_ZSTD.

  11. pg_basebackup: Clean up some bogus file extension tests.

  12. pg_basebackup: Avoid unclean failure with server-compression and -D -.

  13. Fix LZ4 tests for remaining buffer space.

  14. Add support for zstd base backup compression.

  15. pg_basebackup: Allow client-side LZ4 (de)compression.

  16. Add suport for server-side LZ4 base backup compression.

  17. Add min() and max() aggregates for xid8.

  18. Remove superfluous variable.

  19. pg_basebackup: Cleaner handling when compression is multiply specified.

  20. Allow server-side compression to be used with -Fp.

  21. pg_basebackup: Fix a couple of recently-introduced bugs.

  22. Tidy up a few cosmetic issues related to pg_basebackup.

  23. Server-side gzip compression.

  24. Unbreak pg_basebackup/t/010_pg_basebackup.pl on msys

  25. Suppress variable-set-but-not-used warning from clang 13.

  26. Extend the options of pg_basebackup to control compression

  27. Support base backup targets.

  28. Modify pg_basebackup to use a new COPY subprotocol for base backups.

  29. Document that tar archives are now properly terminated.

  30. Fix thinko in bbsink_throttle_manifest_contents.

  31. Have the server properly terminate tar archives.

  32. Minimal fix for unterminated tar archive problem.

  33. Introduce 'bbstreamer' abstraction to modularize pg_basebackup.

  34. Introduce 'bbsink' abstraction to modularize base backup code.

  35. Refactor basebackup.c's _tarWriteDir() function.

  36. Flexible options for CREATE_REPLICATION_SLOT.

  37. Flexible options for BASE_BACKUP.

On Sun, Mar 20, 2022 at 03:05:28PM -0400, Robert Haas wrote:
> On Thu, Mar 17, 2022 at 3:41 PM Justin Pryzby <pryzby@telsasoft.com> wrote:
> > -                                                errmsg("unrecognized compression algorithm: \"%s\"",
> > +                                                errmsg("unrecognized compression algorithm \"%s\"",
> >
> > Most other places seem to say "compression method".  So I'd suggest to change
> > that here, and in doc/src/sgml/ref/pg_basebackup.sgml.
> 
> I'm not sure that's really better, and I don't think this patch is
> introducing an altogether novel usage. I think I would probably try to
> standardize on algorithm rather than method if I were standardizing
> the whole source tree, but I think we can leave that discussion for
> another time.

The user-facing docs are already standardized using "compression method", with
2 exceptions, of which one is contrib/ and the other is what I'm suggesting to
make consistent here.

$ git grep 'compression algorithm' doc
doc/src/sgml/pgcrypto.sgml:    Which compression algorithm to use.  Only available if
doc/src/sgml/ref/pg_basebackup.sgml:        compression algorithm is selected, or if server-side compression

> > +                       result->parse_error =
> > +                               pstrdup("found empty string where a compression option was expected");
> >
> > Needs to be localized with _() ?
> > Also, document that it's pstrdup'd.
> 
> Did the latter. The former would need to be fixed in a bunch of places
> and while I'm happy to accept an expert opinion on exactly what needs
> to be done here, I don't want to try to do it and do it wrong. Better
> to let someone with good knowledge of the subject matter patch it up
> later than do a crummy job now.

I believe it just needs _("foo")
See git grep '= _('

I mentioned another issue off-list:
pg_basebackup.c:2741:10: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
 2741 |   Assert(compressloc = COMPRESS_LOCATION_SERVER);
      |          ^~~~~~~~~~~
pg_basebackup.c:2741:3: note: in expansion of macro ‘Assert’
 2741 |   Assert(compressloc = COMPRESS_LOCATION_SERVER);

This crashes the server using your v2 patch:

src/bin/pg_basebackup/pg_basebackup --wal-method fetch -Ft -D - -h /tmp --no-sync --no-manifest --compress=server-zstd:level, |wc -c

I wonder whether the syntax should really use both ":" and ",".
Maybe ":" isn't needed at all.

This patch also needs to update the other user-facing docs.

typo: contain a an

-- 
Justin