Horton

Re: Conflict detection for update_deleted in logical replication

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>
Cc: shveta malik <shveta.malik@gmail.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>
Date: 2025-09-15T04:51:54Z
Lists: pgsql-hackers

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On Fri, Sep 12, 2025 at 3:39 PM Zhijie Hou (Fujitsu)
<houzj.fnst@fujitsu.com> wrote:
>
> Here is the V74 patch which addressed all comments.
>

+ ereport(LOG,
+ errmsg("logical replication worker for subscription \"%s\" will
resume retaining the information for detecting conflicts",
+    MySubscription->name),
+ MySubscription->maxretention
+ ? errdetail("Retention of information used for conflict detection is
now within the max_retention_duration of %u ms.",
+ MySubscription->maxretention)
+ : errdetail("Retention of information used for conflict detection is
now indefinite."));

The detail message doesn't seems to convey the correct meaning as the
duration is compared with something vague. How about changing
errdetail messages as follows:
"Retention is re-enabled as the apply process is advancing its xmin
within the configured max_retention_duration of %u ms."
"Retention is re-enabled as max_retention_duration is set to unlimited."

If you agree with the above then we can consider changing the existing
errdetail related to stop_retention functionality as follows:
"Retention is stopped as the apply process is not advancing its xmin
within the configured max_retention_duration of %u ms."

Apart from these, I have made some cosmetic changes in the attached.

-- 
With Regards,
Amit Kapila.

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.