Horton

Re: trying again to get incremental backup

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Jakub Wartak <jakub.wartak@enterprisedb.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Dilip Kumar <dilipbalaut@gmail.com>, Andres Freund <andres@anarazel.de>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2023-11-27T19:02:59Z
Lists: pgsql-hackers 
On Thu, Nov 23, 2023 at 11:18 PM Thomas Munro <thomas.munro@gmail.com> wrote:
> Robert pinged me to see if I had any ideas.

Thanks, Thomas.

> The reason it fails on Windows is because there is a special code path
> for WIN32 in the patch's src/bin/pg_combinebackup/copy_file.c, but it
> is incomplete: it returns early without feeding the data into the
> checksum, so all the checksums have the same initial and bogus value.
> I commented that part out so it took the normal path like Unix, and it
> passed.

Yikes, that's embarrassing. Thanks for running it down. There is logic
in the caller to figure out whether we need to recompute the checksum
or can reuse one we already have, but copy_file() doesn't understand
that it should take the slow path if a new checksum computation is
required.

> The reason it fails on Linux 32 bit with -fsanitize is because this
> has uncovered a bug in xlogreader.c, which overflows a 32 bit pointer
> when doing a size test that could easily be changed to non-overflowing
> formulation.  AFAICS it is not a live bug because it comes to the
> right conclusion without deferencing the pointer due to other checks,
> but the sanitizer is not wrong to complain about it and I will post a
> patch to fix that in a new thread.  With the draft patch I am testing,
> the sanitizer is happy and this passes too.

Thanks so much.

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

Commits

  1. Minor fixes to pg_combinebackup and its documentation.

  2. Fix defects in PrepareForIncrementalBackup.

  3. Add WALSummarizerLock to wait_event_names.txt

  4. Initialize variable to placate compiler.

  5. Replace nonsense comment with a relevant one.

  6. Fix numerous typos in incremental backup commits.

  7. Add support for incremental backup.

  8. Add a new WAL summarizer process.

  9. Move src/bin/pg_verifybackup/parse_manifest.c into src/common.

  10. Fix brown paper bag bug in 5c47c6546c413d5eb51c1626070a807026e6139d.

  11. Rename pg_verifybackup's JsonManifestParseContext callback functions.

  12. Rename JsonManifestParseContext callbacks.

  13. Change how a base backup decides which files have checksums.

  14. Change struct tablespaceinfo's oid member from 'char *' to 'Oid'

  15. Refactor parse_filename_for_nontemp_relation to parse more.

  16. During online checkpoints, insert XLOG_CHECKPOINT_REDO at redo point.

  17. In basebackup.c, refactor to create read_file_data_into_buffer.

  18. In basebackup.c, refactor to create verify_page_checksum.

  19. Report syncscan position at end of scan.

  20. Exclude additional directories in pg_basebackup

  21. Add new JSON processing functions and parser API.