Horton

Re: Conflict detection for update_deleted in logical replication

shveta malik <shveta.malik@gmail.com>

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From: shveta malik <shveta.malik@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Nisha Moond <nisha.moond412@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, vignesh C <vignesh21@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, shveta malik <shveta.malik@gmail.com>
Date: 2025-09-15T04:55:07Z
Lists: pgsql-hackers 
One concern:

  if (should_stop_conflict_info_retention(rdt_data))
+ {
+ /*
+ * Stop retention if not yet. Otherwise, reset to the initial phase to
+ * retry all phases. This is required to recalculate the current wait
+ * time and resume retention if the time falls within
+ * max_retention_duration.
+ */
+ if (MySubscription->retentionactive)
+ rdt_data->phase = RDT_STOP_CONFLICT_INFO_RETENTION;
+ else
+ reset_retention_data_fields(rdt_data);
+
  return;
+ }

 Instead of above code changes, shall we have:

 if (should_stop_conflict_info_retention(rdt_data))
     rdt_data->phase = RDT_STOP_CONFLICT_INFO_RETENTION;  (always)

And then stop_conflict_info_retention() should have these checks:

if (MySubscription->retentionactive)
{
    ...update flag and perform stop (current functionality)
}
else
{
        Assert(!TransactionIdIsValid(MyLogicalRepWorker->oldest_nonremovable_xid));
        reset_retention_data_fields(rdt_data);
}

thanks
Shveta

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.