On Tue, 11 Jun 2024 at 09:41, Amul Sul <sula...@gmail.com> wrote: > > On Mon, Jun 10, 2024 at 5:00 PM vignesh C <vignes...@gmail.com> wrote: >> >> On Mon, 10 Jun 2024 at 12:24, Amul Sul <sula...@gmail.com> wrote: >> > >> > >> > >> > On Sat, Jun 8, 2024 at 6:43 PM vignesh C <vignes...@gmail.com> wrote: >> >> >> >> On Wed, 5 Jun 2024 at 14:11, Amit Kapila <amit.kapil...@gmail.com> wrote: >> >> [...] >> >> A new catalog table, pg_subscription_seq, has been introduced for >> >> mapping subscriptions to sequences. Additionally, the sequence LSN >> >> (Log Sequence Number) is stored, facilitating determination of >> >> sequence changes occurring before or after the returned sequence >> >> state. >> > >> > >> > Can't it be done using pg_depend? It seems a bit excessive unless I'm >> > missing >> > something. >> >> We'll require the lsn because the sequence LSN informs the user that >> it has been synchronized up to the LSN in pg_subscription_seq. Since >> we are not supporting incremental sync, the user will be able to >> identify if he should run refresh sequences or not by checking the lsn >> of the pg_subscription_seq and the lsn of the sequence(using >> pg_sequence_state added) in the publisher. Also, this parallels our >> implementation for pg_subscription_seq and will aid in expanding for >> a) incremental synchronization and b) utilizing workers for >> synchronization using sequence states if necessary. >> >> How do you track sequence mapping with the publication? >> >> In the publisher we use pg_publication_rel and >> pg_publication_namespace for mapping the sequences with the >> publication. > > > Thanks for the explanation. I'm wondering what the complexity would be, if we > wanted to do something similar on the subscriber side, i.e., tracking via > pg_subscription_rel.
Because we won't utilize sync workers to synchronize the sequence, and the sequence won't necessitate sync states like init, sync, finishedcopy, syncdone, ready, etc., initially, I considered keeping the sequences separate. However, I'm ok with using pg_subscription_rel as it could potentially help in enhancing incremental synchronization and parallelizing later on. Regards, Vignesh
