Re: refactoring basebackup.c (zstd workers)

Justin Pryzby <pryzby@telsasoft.com>

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" <pgsql-hackers@postgresql.org>, tushar <tushar.ahuja@enterprisedb.com>
Date: 2022-03-14T17:11:52Z
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 Mon, Mar 14, 2022 at 01:02:20PM -0400, Robert Haas wrote:
> On Mon, Mar 14, 2022 at 12:35 PM Justin Pryzby <pryzby@telsasoft.com> wrote:
> > I suggest to use a syntax that's more general than that, maybe something like
> >
> > :[level=]N,parallel=N,flag,flag,...
> >
> > For example, someone may want to use zstd "long" mode or (when it's released)
> > rsyncable mode, or specify fine-grained compression parameters (strategy,
> > windowLog, hashLog, etc).
> 
> That's an interesting idea. I wonder what the replication protocol
> ought to look like in that case. Should we have a COMPRESSION_DETAIL
> argument that is just a string, and let the server parse it out? Or
> separate protocol-level options? It does feel reasonable to have both
> COMPRESSION_LEVEL and COMPRESSION_WORKERS as first-class options, but
> I don't know that we want COMPRESSION_HASHLOG true as part of our
> first-class grammar.

I was only referring to the user-facing grammar.

Internally, I was thinking they'd all be handled as first-class options, with
separate struct fields and separate replication protocol options.  If an option
isn't known, it'd be rejected on the client side, rather than causing an error
on the server.

Maybe there'd be an option parser for this in common/ (I think that might
require having new data structure there too, maybe one for each compression
method, or maybe a union{} to handles them all).  Most of the ~100 lines to
support wal_compression='zstd:N' are to parse out the N.

-- 
Justin