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