On Tue, 2021-01-05 at 09:17 -0800, Jeff Davis wrote: > The reason I ask is because it makes clients that do pipelining more > complex. If the server always enters copy mode, then the client can > send a CopyDone and then pipeline more requests behind it. But if the > server may or may not enter copy mode, then the client needs to wait > until it sees a CopyBothResponse before any new requests can be > pipelined.
In an offline conversation with Andres, he pointed out that we can never be sure that we'll enter COPY mode, because the START_REPLICATION command could throw an error. Therefore we need to always wait for the CopyBothResponse, and can't pipeline any new commands until we get it. Regards, Jeff Davis