Re: hung postmaster when client machine dies?

Goulet, Dick wrote:
> Hope you don't mind if I disagree. Most OS's that have a tcp/ip
> layer also have a parameter therein called tcp_keep_alive. They also
> set this parameter to infinity. The purpose of tcp_keep_alive is to
> have the OS kernel periodically verify that all tcp/ip connections it
> is managing are still functioning every so often. Basically the OS
> sends a probe packet down the line to the to the client machine. If
> it bounces back the connection is dead & the OS can do what it has
> to, which will then notify postmaster just like you manually did.
> I'd contact your OS vendor for information of what tcp_keep_alive is
> set to by default and how you can change it.

On the other hand I suggest that you *do not* change this value, even if you
know how, without being very careful understanding what it means.

Changing the system-wide TCP KA time can have unforseen effects on other,
unrelated functions of the systems concerned.

This is simply why most long lived protocols layered over TCP also tend to
have their own keep alive PDUs.

Peter