On Jun 19, 2010, at 21:13 , Tom Lane wrote: > Robert Haas <robertmh...@gmail.com> writes: >> Right now, if the SR master reboots unexpectedly (say, power plug pull >> and restart), the slave never notices. It just sits there forever >> waiting for the next byte of data from the master to arrive (which it >> never will). > > This is nonsense --- the slave's kernel *will* eventually notice that > the TCP connection is dead, and tell walreceiver so. I don't doubt > that the standard TCP timeout is longer than people want to wait for > that, but claiming that it will never happen is simply wrong.
No, Robert is correct AFAIK. If you're *waiting* for data, TCP generates no traffic (expect with keepalive enabled). From the slave's kernel POV, a dead master is therefore indistinguishable from a inactive master. Things are different from a sender's POV, though. Since sent data is ACK'ed by the receiving end, the TCP stack can (and does) detect a broken connection. best regards, Florian Pflug -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
