RE: Optionally automatically disable logical replication subscriptions on error

On Wednesday, March 2, 2022 9:34 AM Peter Smith <smithpb2250(at)gmail(dot)com> wrote:
> Please see below my review comments for v24.
Thank you for checking my patch !

> ======
>
> 1. src/backend/replication/logical/worker.c - start_table_sync
>
> + /* Report the worker failed during table synchronization */
> + pgstat_report_subscription_error(MySubscription->oid,
> + !am_tablesync_worker());
>
> (This review comment is just FYI in case you did not do this deliberately)
>
> FYI, you didn't really need to call am_tablesync_worker() here because it is
> already asserted for the sync phase that it MUST be a tablesync worker.
>
> OTOH, IMO it documents the purpose of the parm so if it was deliberate then
> that is OK too.
Fixed.

> ~~~
>
> 2. src/backend/replication/logical/worker.c - start_table_sync
>
> + PG_CATCH();
> + {
> + /*
> + * Abort the current transaction so that we send the stats message in
> + * an idle state.
> + */
> + AbortOutOfAnyTransaction();
> +
> + /* Report the worker failed during table synchronization */
> + pgstat_report_subscription_error(MySubscription->oid,
> + !am_tablesync_worker());
> +
>
> [Maybe you will say that this review comment is unrelated to disable_on_err,
> but since this is a totally new/refactored function then I think maybe there is no
> problem to make this change at the same time. Anyway there is no function
> change, it is just rearranging some comments.]
>
> I felt the separation of those 2 statements and comments makes that code less
> clean than it could/should be. IMO they should be grouped together.
>
> SUGGESTED
> /*
> * Report the worker failed during table synchronization. Abort the
> * current transaction so that the stats message is sent in an idle
> * state.
> */
> AbortOutOfAnyTransaction();
> pgstat_report_subscription_error(MySubscription->oid, !am_tablesync_work
> er());
I think this is OK. Thank you for suggestion. Fixed.

> ~~~
>
> 3. src/backend/replication/logical/worker.c - start_apply
>
> + /*
> + * Abort the current transaction so that we send the stats message in
> + * an idle state.
> + */
> + AbortOutOfAnyTransaction();
> +
> + /* Report the worker failed during the application of the change */
> + pgstat_report_subscription_error(MySubscription->oid,
> + !am_tablesync_worker());
>
> Same comment as #2 above, but this code fragment is in start_apply function.
Fixed.

> ~~~
>
> 4. src/test/subscription/t/029_disable_on_error.pl - comment
>
> +# Drop the unique index on the sub and re-enabled the subscription.
> +# Then, confirm that we have finished the apply.
>
> SUGGESTED (tweak the comment wording)
> # Drop the unique index on the sub and re-enable the subscription.
> # Then, confirm that the previously failing insert was applied OK.
Fixed.

Best Regards,
Takamichi Osumi