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: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, Nisha Moond <nisha.moond412@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, shveta malik <shveta.malik@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2024-12-04T10:59:23Z
Lists: pgsql-hackers

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On Tue, Dec 3, 2024 at 9:17 AM Zhijie Hou (Fujitsu)
<houzj.fnst@fujitsu.com> wrote:
>
> Also, I removed a change in wait_for_local_flush() which was mis-added in V13_2
> patch.
>

1.
+ if (can_advance_nonremovable_xid(&data, last_recv_timestamp))
+ maybe_advance_nonremovable_xid(&data);

In can_advance_nonremovable_xid(), we determine whether to advance the
oldest xid based on 'last_recv_timestamp' and then again in
maybe_advance_nonremovable_xid()->get_candidate_xid(), we compare it
with the current time. How does that make sense? Shall we use
'last_recv_timestamp' directly in get_candidate_xid() as that will
avoid the additional time check in can_advance_nonremovable_xid()?

2.
+ TimestampTz next_attempt_time; /* when to attemp to advance the xid during
+ * change application */
+} RetainConflictInfoData;

This new variable introduced in this version is not used in the patch.
Any reason or just a leftover?

Apart from the above, I have made a few updates in the comments in the
attached. Please include those after review.

-- 
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.