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Re: pg_waldump: support decoding of WAL inside tarfile

amul sul <sulamul@gmail.com>

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From: Amul Sul <sulamul@gmail.com>
To: Andrew Dunstan <andrew@dunslane.net>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Michael Paquier <michael@paquier.xyz>, Zsolt Parragi <zsolt.parragi@percona.com>, Robert Haas <robertmhaas@gmail.com>, Chao Li <li.evan.chao@gmail.com>, Jakub Wartak <jakub.wartak@enterprisedb.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2026-03-21T15:35:50Z
Lists: pgsql-hackers

Attachments

On Sat, Mar 21, 2026 at 5:51 PM Andrew Dunstan <andrew@dunslane.net> wrote:
>
>
> On 2026-03-21 Sa 2:34 AM, Tom Lane wrote:
>
> Michael Paquier <michael@paquier.xyz> writes:
>
> On Fri, Mar 20, 2026 at 11:49:02PM -0400, Tom Lane wrote:
>
> Buildfarm members batta and hachi don't like this very much.
>
> I did not look at what's happening on the host, but it seems like a
> safe bet to assume that we are not seeing many failures in the
> buildfarm because we don't have many animals that have the idea to add
> --with-zstd to their build configuration, like these two ones.
>
> That may be part of the story, but only part.  I spent a good deal of
> time trying to reproduce batta & hachi's configurations locally, on
> several different platforms, but still couldn't duplicate what they
> are showing.
>
>
>
>
>
> Yeah, I haven't been able to reproduce it either. But while investigating I found a couple of issues. We neglected to add one of the tests to meson.build, and we neglected to close some files, causing errors on windows.
>

While the proposed fix of closing the file pointer before returning is
correct, we also need to ensure the file is reopened in the next call
to spill any remaining buffered data. I’ve made a small update to
Andrew's 0001 patch to handle this. Also, changes to meson.build don't
seem to be needed as we haven't committed that file yet (unless I am
missing something).

I’ve also reattached the other patches so they don't get lost: v2-0002
is Andrew's patch for the archive streamer, and v2-0003 is the patch I
posted previously [1].


Regards,
Amul

1] http://postgr.es/m/CAAJ_b95L5J7bjRNDjRj6WgqFcQeaBD+JX3sAuxPA4uopqEThxA@mail.gmail.com

Commits

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

  1. Use size_t instead of Size in pg_waldump

  2. More tar portability adjustments.

  3. Further harden tests that might use not-so-compatible tar versions.

  4. Harden astreamer tar parsing logic against archives it can't handle.

  5. Fix pg_waldump/t/001_basic.pl with BSD tar on ZFS.

  6. Remove a low-value, high-risk optimization in pg_waldump.

  7. Fix misuse of simplehash.h hash operations in pg_waldump.

  8. Fix file descriptor leakages in pg_waldump.

  9. Fix poorly-sized buffers in astreamer compression modules.

  10. Remove read_archive_file()'s "count" parameter.

  11. Report detailed errors from XLogFindNextRecord() failures.

  12. Fix assorted bugs in archive_waldump.c.

  13. Remove nonfunctional tar file trailer size check.

  14. Fix finalization of decompressor astreamers.

  15. Move tar detection and compression logic to common.

  16. pg_verifybackup: Enable WAL parsing for tar-format backups

  17. pg_waldump: Add support for reading WAL from tar archives

  18. pg_waldump: Preparatory refactoring for tar archive WAL decoding.

  19. pg_waldump: Remove file-level global WalSegSz.

  20. pg_verifybackup: Verify tar-format backups.