On Thu, Oct 28, 2021 at 1:05 PM Amit Kapila <amit.kapil...@gmail.com> wrote: > > On Thu, Oct 28, 2021 at 7:49 AM Masahiko Sawada <sawada.m...@gmail.com> wrote: > > > > On Wed, Oct 27, 2021 at 2:43 PM Amit Kapila <amit.kapil...@gmail.com> wrote: > > > > > > On Wed, Oct 27, 2021 at 10:43 AM Masahiko Sawada <sawada.m...@gmail.com> > > > wrote: > > > > > > > > > > BTW how useful is specifying LSN instead of XID in practice? Given > > > > > > that this skipping behavior is used to skip the particular > > > > > > transaction > > > > > > (or its part of operations) in question, I’m not sure specifying LSN > > > > > > or time is useful. > > > > > > > > > > > > > > > > I think if the user wants to skip multiple xacts, she might want to > > > > > use the highest LSN to skip instead of specifying individual xids. > > > > > > > > I think it assumes that the situation where the user already knows > > > > multiple transactions that cannot be applied on the subscription but > > > > how do they know? > > > > > > > > > > Either from the error messages in the server log or from the new view > > > we are planning to add. I think such a case is possible during the > > > initial synchronization phase where apply worker went ahead then > > > tablesync worker by skipping to apply the changes on the corresponding > > > table. After that it is possible, that table sync worker failed during > > > copy and apply worker fails during the processing of some other rel. > > > > Does it mean that if both initial copy for the corresponding table by > > table sync worker and applying changes for other rels by apply worker > > fail, we skip both by specifying LSN? > > > > Yes. > > > If so, can't we disable the > > initial copy for the table and skip only the changes for other rels > > that cannot be applied? > > > > But anyway you need some way to skip changes via a particular > tablesync worker so that it can mark the relation in 'ready' state.
Right. > I > think one can also try to use disable_on_error option in such > scenarios depending on how we expose it. Say, if the option means that > all workers (apply or table sync) should be disabled on an error then > it would be a bit tricky but if we can come up with a way to behave > differently for different workers then it is possible to disable one > set of workers and skip the changes in another set of workers. Yes, I would prefer to skip individual transactions in question rather than skip changes until the particular LSN. It’s not advisable to use LSN to skip changes since it has a risk of skipping unrelated changes too. Regards, -- Masahiko Sawada EDB: https://www.enterprisedb.com/
