Horton

Re: Conflict detection for update_deleted in logical replication

Nisha Moond <nisha.moond412@gmail.com>

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From: Nisha Moond <nisha.moond412@gmail.com>
To: "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, Masahiko Sawada <sawada.mshk@gmail.com>, shveta malik <shveta.malik@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2024-10-25T08:51:07Z
Lists: pgsql-hackers 
> Here is the V5 patch set which addressed above comments.
>
Here are a couple of comments on v5 patch-set -

1) In FindMostRecentlyDeletedTupleInfo(),

+ /* Try to find the tuple */
+ while (index_getnext_slot(scan, ForwardScanDirection, scanslot))
+ {
+ Assert(tuples_equal(scanslot, searchslot, eq));
+ update_recent_dead_tuple_info(scanslot, oldestXmin, delete_xid,
+   delete_time, delete_origin);
+ }

In my tests, I found that the above assert() triggers during
unidirectional replication of an update on a table. While doing the
replica identity index scan, it can only ensure to match the indexed
columns value, but the current Assert() assumes all the column values
should match, which seems wrong.

2) Since update_deleted requires both 'track_commit_timestamp' and the
'detect_update_deleted' to be enabled, should we raise an error in the
CREATE and ALTER subscription commands when track_commit_timestamp=OFF
but the user specifies detect_update_deleted=true?

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.