Horton

RE: Conflict detection for update_deleted in logical replication

Zhijie Hou (Fujitsu) <houzj.fnst@fujitsu.com>

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From: "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: shveta malik <shveta.malik@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, vignesh C <vignesh21@gmail.com>, Nisha Moond <nisha.moond412@gmail.com>
Date: 2025-08-18T04:20:12Z
Lists: pgsql-hackers 
On Saturday, August 16, 2025 7:44 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> Here are review comments on v62 patch:

Thanks for the comments!

> 
> 
> ---
> +                else if (IsSet(supported_opts,
> SUBOPT_MAX_CONFLICT_RETENTION_DURATION) &&
> +                                 strcmp(defel->defname,
> "max_conflict_retention_duration") == 0)
> +                {
> +                        if (IsSet(opts->specified_opts,
> SUBOPT_MAX_CONFLICT_RETENTION_DURATION))
> +                                errorConflictingDefElem(defel, pstate);
> +
> +                        opts->specified_opts |=
> SUBOPT_MAX_CONFLICT_RETENTION_DURATION;
> +                        opts->maxconflretention = defGetInt32(defel);
> +                }
> 
> The new subscription parameter accepts only integers and takes it as
> milliseconds, but I think it would be relatively rare that users
> specify this parameter to less than 1 second. I guess it would be a
> good idea to accept string representation of a duration too such as
> '10 min' like we do for parsing GUC parameter values.

We can consider implementing this. However, currently, other similar non-GUC
time-based options do not support unit specification, such as
autovacuum_vacuum_cost_delay and log_autovacuum_min_duration. As such, including
it in max_conf_xx_retention would require new parsing logic. Perhaps we can
treat this as a separate improvement and explore its implementation later, based
on user feedback ?

Best Regards,
Hou zj

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.