Horton

Re: Conflict detection for update_deleted in logical replication

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>
Cc: shveta malik <shveta.malik@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Nisha Moond <nisha.moond412@gmail.com>, Masahiko Sawada <sawada.mshk@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>
Date: 2025-09-07T21:36:32Z
Lists: pgsql-hackers 
Coverity is not happy with commit a850be2fe:

/srv/coverity/git/pgsql-git/postgresql/src/backend/replication/logical/worker.c: 3276             in FindDeletedTupleInLocalRel()
3270     		 * maybe_advance_nonremovable_xid() for details).
3271     		 */
3272     		LWLockAcquire(LogicalRepWorkerLock, LW_SHARED);
3273     		leader = logicalrep_worker_find(MyLogicalRepWorker->subid,
3274     										InvalidOid, false);
3275     
>>>     CID 1665367:         Null pointer dereferences  (NULL_RETURNS)
>>>     Dereferencing a pointer that might be "NULL" "&leader->relmutex" when calling "tas".
3276     		SpinLockAcquire(&leader->relmutex);
3277     		oldestxmin = leader->oldest_nonremovable_xid;
3278     		SpinLockRelease(&leader->relmutex);
3279     		LWLockRelease(LogicalRepWorkerLock);
3280     	}

I think Coverity has a point.  AFAICS every other call of
logicalrep_worker_find() guards against a NULL result,
so why is it okay for this one to dump core on NULL?

			regards, tom lane

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.