On Mon, Mar 7, 2022 at 9:26 AM Dilip Kumar <dilipbal...@gmail.com> wrote: > > On Wed, Feb 23, 2022 at 11:59 AM vignesh C <vignes...@gmail.com> wrote: > > 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 > > > > 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); > > I haven't yet gone through the patch, but I have a question about the > idea. Suppose I want to set up a logical replication like, > node1->node2->node3->node1. So how would I create the subscriber at > node1? only_local=on or off?. I mean on node1, I want the changes > from node3 which are generated on node3 or which are replicated from > node2 but I do not want changes that are replicated from node1 itself? > So if I set only_local=on then node1 will not get the changes > replicated from node2, is that right? and If I set only_local=off then > it will create the infinite loop again? So how are we protecting > against this case? >
In the above topology if you want local changes from both node3 and node2 then I think the way to get that would be you have to create two subscriptions on node1. The first one points to node2 (with only_local=off) and the second one points to node3 (with only_local =off). Will that address your case or am I missing something? -- With Regards, Amit Kapila.
