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: Tom Lane <tgl@sss.pgh.pa.us>, Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>, 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: 2022-03-28T20:53:29Z
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.

Attachments

On Mon, Mar 28, 2022 at 03:50:50PM -0400, Robert Haas wrote:
> On Sun, Mar 27, 2022 at 1:47 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > Coverity has a nitpick about this:
> >
> > /srv/coverity/git/pgsql-git/postgresql/src/common/backup_compression.c: 194 in parse_bc_specification()
> > 193                     /* Advance to next entry and loop around. */
> > >>>     CID 1503251:  Null pointer dereferences  (REVERSE_INULL)
> > >>>     Null-checking "vend" suggests that it may be null, but it has already been dereferenced on all paths leading to the check.
> > 194                     specification = vend == NULL ? kwend + 1 : vend + 1;
> > 195             }
> > 196     }
> >
> > Not sure if you should remove this null-check or add some other ones,
> > but I think you ought to do one or the other.
> 
> Yes, I think this is buggy.  I think there's only a theoretical bug
> right now, because the only keyword we have is "level" and that
> requires a value. But if I add an example keyword that does not
> require an associated value (as demonstrated in the attached patch)
> and do something like pg_basebackup -cfast -D whatever --compress
> lz4:example, then the present code will dereference "vend" even though
> it's NULL, which is not good. The attached patch also shows how I
> think that should be fixed.
> 
> As I hope is apparent, the first hunk of this patch is not for commit,
> and the second hunk is for commit.

Confirmed that it's a real issue with my patch for zstd long match mode.  But
you need to specify another option after the value-less flag option for it to
crash.

I suggest to write it differently, as in 0002.

This also fixes some rebase-induced errors with my previous patches, and adds
expect_boolean().