On Tue, Mar 1, 2022 at 4:12 PM kuroda.hay...@fujitsu.com <kuroda.hay...@fujitsu.com> wrote: > > Hi Vignesh, > > > In logical replication, currently Walsender sends the data that is > > generated locally and the data that are replicated from other > > instances. This results in infinite recursion in circular logical > > replication setup. > > Thank you for good explanation. I understand that this fix can be used > for a bidirectional replication. > > > Here there are two problems for the user: a) incremental > > synchronization of table sending both local data and replicated data > > by walsender b) Table synchronization of table using copy command > > sending both local data and replicated data > > So you wanted to solve these two problem and currently focused on > the first one, right? We can check one by one. > > > For the first problem "Incremental synchronization of table by > > Walsender" can be solved by: > > Currently the locally generated data does not have replication origin > > associated and the data that has originated from another instance will > > have a replication origin associated. We could use this information to > > differentiate locally generated data and replicated data and send only > > the locally generated data. This "only_local" could be provided as an > > option while subscription is created: > > ex: CREATE SUBSCRIPTION sub1 CONNECTION 'dbname =postgres port=5433' > > PUBLICATION pub1 with (only_local = on); > > Sounds good, but I cannot distinguish whether the assumption will keep. > > I played with your patch, but it could not be applied to current master. > I tested from bd74c40 and I confirmed infinite loop was not appeared. > > local_only could not be set from ALTER SUBSCRIPTION command. > Is it expected?
I felt changing only_local option might be useful for the user while modifying the subscription like setting it with a different set of publications. Changes for this are included in the v2 patch attached at [1]. [2] - https://www.postgresql.org/message-id/CALDaNm0WSo5369pr2eN1obTGBeiJU9cQdF6Ju1sC4hMQNy5BfQ%40mail.gmail.com Regards, Vignesh