Horton

RE: Conflict detection for update_deleted in logical replication

Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>

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From: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>
To: 'Michail Nikolaev' <michail.nikolaev@gmail.com>
Cc: "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>, Amit Kapila <amit.kapila16@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, shveta malik <shveta.malik@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Peter Smith <smithpb2250@gmail.com>, Nisha Moond <nisha.moond412@gmail.com>
Date: 2024-10-31T00:55:01Z
Lists: pgsql-hackers 
Dear Mikhail,

Thanks for the reply!

> > Anyway, this topic introduces huge complexity and is not mandatory for update_deleted
> > detection. We can work on it in later versions based on the needs.
>
> From my perspective, this is critical for databases. REINDEX CONCURRENTLY is typically run
> in production databases on regular basic, so any master-master system should be unaffected by it.

I think you do not understand what I said correctly. The main point here is that
the index scan is not needed to detect the update_deleted. In the first version
workers can do the normal sequential scan instead. This workaround definitely does
not affect REINDEX CONCURRENTLY.
After the patch being good shape or pushed, we can support using the index to find
the dead tuple, at that time we can consider how we ensure the index contains the entry
for dead tuples.

Best regards,
Hayato Kuroda
FUJITSU LIMITED

Commits

  1. Fix intermittent BF failures in 035_conflicts.

  2. Resume conflict-relevant data retention automatically.

  3. Fix intermittent test failure introduced in 6456c6e2c4.

  4. Fix Coverity issue reported in commit a850be2fe.

  5. Add test to prevent premature removal of conflict-relevant data.

  6. Post-commit review fixes for 228c370868.

  7. Add max_retention_duration option to subscriptions.

  8. Detect and report update_deleted conflicts.

  9. Preserve conflict-relevant data during logical replication.

  10. Integrate FullTransactionIds deeper into two-phase code

  11. Improve checks for GUC recovery_target_timeline

  12. Prevent excessive delays before launching new logrep workers.

  13. Keep WAL segments by slot's last saved restart LSN

  14. Rework some code handling pg_subscription data in psql and pg_dump

  15. Use generateClonedIndexStmt to propagate CREATE INDEX to partitions.