On 2022-Apr-08, Amit Kapila wrote: > On Thu, Mar 17, 2022 at 3:36 AM Alvaro Herrera <alvhe...@alvh.no-ip.org> > wrote: > > > > Did you see some old code I wrote towards this goal? > > https://www.postgresql.org/message-id/20150215044814.gl3...@alvh.no-ip.org > > The intention was that DDL would produce some JSON blob that accurately > > describes the DDL that was run; > > I have read that thread and found one of your emails [1] where you > seem to be saying that JSON representation is not required for BDR. > Will in some way going via JSON blob way make this project > easier/better?
I don't know if replication support will be easier by using JSON; I just think that JSON makes the overall feature more easily usable for other purposes. I am not familiar with BDR replication nowadays. > For runtime conditions, one of the things you have mentioned in that > thread is to add schema name in the statement at the required places > which this patch deals with in a different way by explicitly sending > it along with the DDL statement. Hmm, ok. The point of the JSON-blob route is that the publisher sends a command representation that can be parsed/processed/transformed arbitrarily by the subscriber using generic rules; it should be trivial to use a JSON tool to change schema A to schema B in any arbitrary DDL command, and produce another working DDL command without having to know how to write that command specifically. So if I have a rule that "schema A there is schema B here", all DDL commands can be replayed with no further coding (without having to rely on getting the run-time search_path correct.) -- Álvaro Herrera 48°01'N 7°57'E — https://www.EnterpriseDB.com/ "El sudor es la mejor cura para un pensamiento enfermo" (Bardia)
