Horton

Re: refactoring basebackup.c

Robert Haas <robertmhaas@gmail.com>

View thread
From: Robert Haas <robertmhaas@gmail.com>
To: "Shinoda, Noriyoshi (PN Japan FSIP)" <noriyoshi.shinoda@hpe.com>
Cc: Justin Pryzby <pryzby@telsasoft.com>, Jeevan Ladhe <jeevanladhe.os@gmail.com>, Dipesh Pandit <dipesh.pandit@gmail.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: 2022-02-14T16:00:18Z
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 Sat, Feb 12, 2022 at 1:01 AM Shinoda, Noriyoshi (PN Japan FSIP)
<noriyoshi.shinoda@hpe.com> wrote:
> Thank you for developing a great feature.
> The current help message shown below does not seem to be able to specify the 'client-' or 'server-' for lz4 compression.
>  --compress = {[{client, server}-]gzip, lz4, none}[:LEVEL]
>
> The attached small patch fixes the help message as follows:
>  --compress = {[{client, server}-]{gzip, lz4}, none}[:LEVEL]

Hmm. After studying this a bit more closely, I think this might
actually need a bit more revision than what you propose here. In most
places, we use vertical bars to separate alternatives:

  -X, --wal-method=none|fetch|stream

But here, we're using commas in some places and the word "or" in one
case as well:

  -Z, --compress={[{client,server}-]gzip,lz4,none}[:LEVEL] or [LEVEL]

We're also not consistently using braces for grouping, which makes the
order of operations a bit unclear, and it makes no sense to put
brackets around LEVEL when it's the only thing that's part of that
alternative.

A more consistent way of writing the supported syntax would be like this:

  -Z, --compress={[{client|server}-]{gzip|lz4}}[:LEVEL]|LEVEL|none}

I would be somewhat inclined to leave the level-only variant
undocumented and instead write it like this:

  -Z, --compress={[{client|server}-]{gzip|lz4}}[:LEVEL]|none}

-- 
Robert Haas
EDB: http://www.enterprisedb.com