On Monday, June 16, 2025, Tatsuo Ishii <
ishii@postgresql.org> wrote:
My question is, BackendKeyData is mandatory or not. Currently
Pgpool-II raises a fatal error if BackendKeyData is not sent before
ReadyForQuery arrives. This is because without the message, frontend
cannot send a CancelRequest message later on, as there's no secret
key.
I wouldn’t expect a proxy to make a judgement here; but to simply forward what does show up and otherwise stay silent. If there is proxy layer code needed to deal with its absence ignoring the cancel attempt with a log warning would be sufficient. Otherwise, the user has made their choices and this is an optional feature in practice (though resorting to pg_cancel_query make be required for truly hung processes).
David J.
