Craig Ringer <cr...@2ndquadrant.com> writes: > Hi all > To support transparent client-side failover in BDR, it's necessary to > know what the LSN of a node was at the time a transaction committed and > keep track of that in the client/proxy.
> I'm thinking about adding a new message type in the protocol that gets > sent immediately before CommandComplete, containing the LSN of the > commit. Clients would need to enable the sending of this message with a > GUC that they set when they connect, so it doesn't confuse clients that > aren't expecting it or aware of it. FWIW, I think it's a seriously bad idea to expose LSNs in the protocol at all. What happens five years from now when we switch to some other implementation that doesn't have LSNs? I don't mind if you expose some other way to inquire about LSNs, but let's *not* embed it into the wire protocol. Not even as an option. This position also obviates the need to complain about having a GUC that changes the protocol-level behavior, which is also a seriously bad idea. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers