On 9/5/07, Martijn van Oosterhout <kleptog@svana.org> wrote:
> On Wed, Sep 05, 2007 at 10:44:20AM -0700, Trevor Talbot wrote:
> > Unless psql is turning on keepalive or similar, or the OS is forcing
> > it on by default, there are no timeouts for idle TCP connections. If
> > the command was transported to the server successfully and psql was
> > just waiting for a result, the connection is idle and nothing will
> > happen if the server end suddenly goes away.
>
> Well, any TCP implementation has to support keepalives and generally
Er, has to? Unless there's a new RFC I haven't seen lately, keepalive
is purely a vendor behavior extension. It's also known that some
older stacks interpreted the TCP spec slightly differently and don't
correctly respond to keepalive packets.
Keepalive is definitely useful, but you can't assume anything about it
being present, enabled, or working by default. It's only seen
mainstream use in recent years.