Horton

Re: trying again to get incremental backup

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Dilip Kumar <dilipbalaut@gmail.com>, Andres Freund <andres@anarazel.de>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Peter Eisentraut <peter@eisentraut.org>
Date: 2023-11-16T17:50:43Z
Lists: pgsql-hackers 
On Thu, Nov 16, 2023 at 12:34 PM Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
> Putting those two thoughts together, I think pg_basebackup with
> --progress could tell you "still waiting for the summary file up to LSN
> %X/%X to appear, and the walsummarizer is currently handling lsn %X/%X"
> or something like that.  This would probably require two concurrent
> connections, one to run BASE_BACKUP and another to inquire server state;
> but this should easy enough to integrate together with parallel
> basebackup later.

I had similar thoughts, except I was thinking it would be better to
have the warnings be generated on the server side. That would save the
need for a second libpq connection, which would be good, because I
think adding that would result in a pretty large increase in
complexity and some not-so-great user-visible consequences. In fact,
my latest thought is to just remove the timeout altogether, and emit
warnings like this:

WARNING:  still waiting for WAL summarization to reach %X/%X after %d
seconds, currently at %X/%X

We could emit that every 30 seconds or so until either the situation
resolves itself or the user hits ^C. I think that would be good enough
here. If we want, the interval between messages can be a GUC, but I
don't know how much real need there will be to tailor that.

-- 
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.