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: Masahiko Sawada <sawada.mshk@gmail.com>, shveta malik <shveta.malik@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: 2025-09-12T08:42:31Z
Lists: pgsql-hackers

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On Fri, Sep 12, 2025 at 8:55 AM Zhijie Hou (Fujitsu)
<houzj.fnst@fujitsu.com> wrote:
>
> I agree. Here is a V73 patch that will restart the worker if the retention
> resumes. I also addressed other comments posted by Amit[1].
>

Few comments:
============
* In adjust_xid_advance_interval(), for the case when retention is not
active, we still cap the interval by wal_receiver_status_interval. Is
that required or do we let it go till 3 minutes? We can add a new else
if loop to keep the code clear, if you agree with this.

*
+ /*
+ * Resume retention immediately if required. (See
+ * should_resume_retention_immediately() for details).
+ */
+ if (should_resume_retention_immediately(rdt_data, status_received))
+ rdt_data->phase = RDT_RESUME_CONFLICT_INFO_RETENTION;

Is this optimization for the case when we are in stop_phase or after
stop_phase and someone has changed maxretention to 0? If so, I don't
think it is worth optimizing for such a rare case at the cost of
making code difficult to understand.

Apart from this, I have changed a few comments 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.