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Re: pg_waldump: support decoding of WAL inside tarfile

Andrew Dunstan <andrew@dunslane.net>

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From: Andrew Dunstan <andrew@dunslane.net>
To: Thomas Munro <thomas.munro@gmail.com>, Nazir Bilal Yavuz <byavuz81@gmail.com>
Cc: Sami Imseih <samimseih@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Tomas Vondra <tomas@vondra.me>, Andres Freund <andres@anarazel.de>, Michael Paquier <michael@paquier.xyz>, Amul Sul <sulamul@gmail.com>, Zsolt Parragi <zsolt.parragi@percona.com>, Robert Haas <robertmhaas@gmail.com>, Chao Li <li.evan.chao@gmail.com>, Anthonin Bonnefoy <anthonin.bonnefoy@datadoghq.com>, Fujii Masao <masao.fujii@gmail.com>, Jakub Wartak <jakub.wartak@enterprisedb.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2026-04-10T12:57:14Z
Lists: pgsql-hackers 
On 2026-04-10 Fr 3:57 AM, Thomas Munro wrote:
> Nitpicking code review for commit b15c1513:
>
> +read_archive_wal_page(XLogDumpPrivate *privateInfo, XLogRecPtr targetPagePtr,
> +                     Size count, char *readBuff)
>
> I thought we agreed to stop using Size for new code?  size_t has been
> around since C89.


Must have missed the memo :-(


>
> +               pg_fatal("WAL segment \"%s\" in archive \"%s\" is too short: rea
> d %lld of %lld bytes",
> +                        fname, privateInfo->archive_name,
> +                        (long long int) (count - nbytes),
> +                        (long long int) count);
>
> Why cast to long long int?  That's the sort of thing we used to have
> to do for int64 (but no longer), but here it's size_t anyway.  %zu has
> been around since C99.


will fix. Thanks for looking.


cheers


andrew

--
Andrew Dunstan
EDB:https://www.enterprisedb.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.