RE: Conflict detection for update_deleted in logical replication
Zhijie Hou (Fujitsu) <houzj.fnst@fujitsu.com>
Attachments
- v41-0006-Allow-altering-retain_conflict_info-for-enabled-.patch (application/octet-stream) patch v41-0006
- v41-0001-Retain-the-information-useful-for-detecting-conf.patch (application/octet-stream) patch v41-0001
- v41-0002-Introduce-a-new-GUC-max_conflict_retention_durat.patch (application/octet-stream) patch v41-0002
- v41-0003-Re-create-the-replication-slot-if-the-conflict-r.patch (application/octet-stream) patch v41-0003
- v41-0004-Add-a-tap-test-to-verify-the-management-of-the-n.patch (application/octet-stream) patch v41-0004
- v41-0005-Support-the-conflict-detection-for-update_delete.patch (application/octet-stream) patch v41-0005
On Tue, Jun 24, 2025 at 6:22 PM shveta malik wrote:
>
> On Mon, Jun 23, 2025 at 4:20 PM Zhijie Hou (Fujitsu)
> <houzj.fnst@fujitsu.com> wrote:
> >
> >
> > Here is the V40 patch set
>
> Thanks for the patches. Few comments:
>
> 1)
> In get_subscription_info(), we are doing COUNT of rci-subscriptions using
> below query:
> SELECT count(*) AS nsub, COUNT(CASE WHEN subretainconflictinfo THEN 1
> END) AS retain_conflict_info FROM pg_catalog.pg_subscription;
>
> And then we are doing:
> cluster->sub_retain_conflict_info = (strcmp(PQgetvalue(res, 0,
> i_retain_conflict_info), "1") == 0);
>
> i.e. get the value and compare with "1". If the count of such subs is say 2,
> won't it fail and will set sub_retain_conflict_info as 0?
Right, it could return wrong results. I have changed it to count(*) xx > 0
so that it can return directly boolean value.
>
> 2)
> create_logical_replication_slots(void)
> {
> + if (!count_old_cluster_logical_slots())
> + return;
> +
>
> We shall get rid of count_old_cluster_logical_slots() here as the caller is
> checking it already.
Removed.
>
> 3)
> We can move the 'old_cluster.sub_retain_conflict_info' check from
> create_conflict_detection_slot() to its caller. Then it will be more informative
> and consistent with how we check migrate_logical_slots outside of
> create_conflict_detection_slot()
Moved.
Here is the V41 patch set which includes the following changes:
0001:
* Rebased due to recent commit fd51941.
* Addressed the comments above.
* Improved some documentation stuff.
* Improved the status message when creating
conflict detection slot in pg_upgrade
0002:
No change
0003:
No change
0004:
No change
0005:
No change
0006:
Rebased due to recent commit fd51941.
Best Regards,
Hou zj
Commits
-
Fix intermittent BF failures in 035_conflicts.
- 0f42206531b3 19 (unreleased) landed
-
Resume conflict-relevant data retention automatically.
- 0d48d393d465 19 (unreleased) landed
-
Fix intermittent test failure introduced in 6456c6e2c4.
- 01d793698f59 19 (unreleased) landed
-
Fix Coverity issue reported in commit a850be2fe.
- 5ac3c1ac22cb 19 (unreleased) landed
-
Add test to prevent premature removal of conflict-relevant data.
- 6456c6e2c4ad 19 (unreleased) landed
-
Post-commit review fixes for 228c370868.
- 1f7e9ba3ac4e 19 (unreleased) landed
-
Add max_retention_duration option to subscriptions.
- a850be2fe653 19 (unreleased) landed
-
Detect and report update_deleted conflicts.
- fd5a1a0c3e56 19 (unreleased) landed
-
Preserve conflict-relevant data during logical replication.
- 228c37086855 19 (unreleased) landed
-
Integrate FullTransactionIds deeper into two-phase code
- 62a17a92833d 19 (unreleased) cited
-
Improve checks for GUC recovery_target_timeline
- fd7d7b719137 19 (unreleased) cited
-
Prevent excessive delays before launching new logrep workers.
- fd519419c948 18.0 cited
-
Keep WAL segments by slot's last saved restart LSN
- ca307d5cec90 18.0 cited
-
Rework some code handling pg_subscription data in psql and pg_dump
- 08691ea958c2 18.0 cited
-
Use generateClonedIndexStmt to propagate CREATE INDEX to partitions.
- 68dfecbef210 18.0 cited