ACK from walreceiver to walsender

Hi Heikki,

http://git.postgresql.org/gitweb?p=users/heikki/postgres.git;a=commit;h=ebaa89ce8906e0ec45f105d083a0360b1f8bc7ca

You dropped all the ACKs from walreceiver to walsender. I have no objection
to that, but I think that walsender should handle at least 'X' (which means
that the standby is closing down the socket) and EOF (which means unexpected
loss of standby connection) messages from walreceiver. Otherwise, walsender
might be unable to detect the shutdown of walreceiver for a while.

Thought?

Regards,

-- 
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center