Heikki Linnakangas ad5f16f724 Improve the protocol between Postgres and page server. ...

- Use different message formats for different kinds of response messages.

- Add an Error message, for passing errors from page server to Postgres.
  Previously, we would respond to 'exists' request with 'false', and
  to 'nblocks' request with 0, if an error happened. Fix those to return
  an error message to the client. GetPage requests had a mechanism to
  return an error, but it was just a flag with no error message.

- Add a flag to requests, to indicate that we actually want the latest
  page version on the timeline, and the LSN is just a hint that we know
  that there haven't been any modifications since that LSN. The flag isn't
  used for anything yet, but I'm planning to use it to fix
  https://github.com/zenithdb/zenith/issues/567

2021-09-17 16:38:14 +03:00

..

postgres @ 4787dcadfe

Improve the protocol between Postgres and page server.

2021-09-17 16:38:14 +03:00