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.
Dick Goulet Senior Oracle DBA Oracle Certified 8i DBA -----Original Message----- From: Jeff [mailto:[EMAIL PROTECTED] Sent: Friday, January 30, 2004 10:18 AM To: Mark Harrison Cc: [EMAIL PROTECTED] Subject: Re: [ADMIN] hung postmaster when client machine dies? On Thu, 29 Jan 2004 17:00:27 -0800 Mark Harrison <[EMAIL PROTECTED]> wrote: > We observed that there was postmaster connected to the ip address > of the downed machine with an "in transaction" status. Killing > that processes unblocked the other processes. > > Is this expected behavior? Was postgres simply waiting for > a failure from the TCP/IP layer? > When a machine simply "goes away" (crashed, unplugged) no packets are sent indicating the socket has closed so PG doesn't know the socket is closed and cannot rollback the transaction. (This is true of any tcp-based protocol). If that connection had a transaction open it'll likely have rows locked. Killing PG caused it to rollback that transaction freeing those locks. Eventually PG would have found out the socket was dead. Most likely if it tried to write to it. -- Jeff Trout <[EMAIL PROTECTED]> http://www.jefftrout.com/ http://www.stuarthamm.net/ ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]