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: "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>
Cc: vignesh C <vignesh21@gmail.com>, Amit Kapila <amit.kapila16@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>, shveta malik <shveta.malik@gmail.com>
Date: 2025-04-29T09:36:06Z
Lists: pgsql-hackers 
On Fri, Apr 25, 2025 at 4:05 PM shveta malik <shveta.malik@gmail.com> wrote:
>
> >
> > Here is V30 patch set includes the following changes:
> >
>
> Thank You for the patch, please find few concerns:
>

Please find few more concerns:

3)
In get_candidate_xid(), we first set candidate_xid_time and later
candidate_xid. And between these 2 there are chances that we return
without updating candidate_xid. See 'Return if the
oldest_nonremovable_xid cannot be advanced ' comment. That will leave
'candidate_xid_time' set to new value while  'candidate_xid' is not
yet set.

4)
Do you think there should be some relation between
'xid_advance_interval' and 'max_conflict_retention_duration'? Should
max of  'xid_advance_interval' be limited by
'max_conflict_retention_duration'. Currently  say
xid_advance_interval' is set to max 3 mins, what if
'max_conflict_retention_duration' is set to 2 mins? In that case we
will not even check for new xids before 3 mins are over, while
'max_conflict_retention_duration' sets a  limit of 2 mins for dead
tuples retention.


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.