On Mon, Jul 19, 2021 at 8:38 PM houzj.f...@fujitsu.com <houzj.f...@fujitsu.com> wrote: > > On July 19, 2021 2:40 PM Masahiko Sawada <sawada.m...@gmail.com> wrote: > > I've attached the updated version patch that incorporated all comments > > I got so far except for the clearing error details part I mentioned > > above. After getting a consensus on those parts, I'll incorporate the > > idea into the patches. > > Hi Sawada-san, > > I am interested in this feature. > After having a look at the patch, I have a few questions about it.
Thank you for having a look at the patches! > > 1) In 0002 patch, it introduces a new view called pg_stat_subscription_errors. > Since it won't be cleaned automatically after we resolve the conflict, do > we > need a reset function to clean the statistics in it ? Maybe something > similar to pg_stat_reset_replication_slot which clean the > pg_stat_replication_slots. Agreed. As Amit also mentioned, providing a reset function to clean the statistics seems a good idea. If the message clearing the stats that is sent after skipping the transaction gets lost, the user is able to reset those stats manually. > > 2) For 0003 patch, When I am faced with a conflict, I set skip_xid = xxx, and > then I resolve the conflict. If I reset skip_xid after resolving the > conflict, will the change(which cause the conflict before) be applied > again ? The apply worker checks skip_xid when it reads the subscription. Therefore, if you reset skip_xid before the apply worker restarts and skips the transaction, the change is applied. But if you reset skip_xid after the apply worker skips transaction, the change is already skipped and your resetting skip_xid has no effect. > > 3) For 0003 patch, if user set skip_xid to a wrong xid which have not been > assigned, and then will the change be skipped when the xid is assigned in > the future even if it doesn't cause any conflicts ? Yes. Currently, setting a correct xid is the user's responsibility. I think it would be better to disable it or emit WARNING/ERROR when the user mistakenly set the wrong xid if we find out a convenient way to detect that. > > Besides, It might be better to add some description of patch in each patch's > commit message which will make it easier for new reviewers to follow. I'll add commit messages in the next version patch. Regards, -- Masahiko Sawada EDB: https://www.enterprisedb.com/
