Add KEEPALIVE option to the socket of backend. This will automatically

terminate the backend that has no frontend anymore.

src/backend/libpq/pqcomm.c

@@ -29,7 +29,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$Id: pqcomm.c,v 1.89 2000/04/14 00:51:58 tgl Exp $
+ *	$Id: pqcomm.c,v 1.90 2000/05/20 13:10:54 ishii Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -375,7 +375,13 @@ StreamConnection(int server_fd, Port *port)
 		if (setsockopt(port->sock, pe->p_proto, TCP_NODELAY,
 					   &on, sizeof(on)) < 0)
 		{
-			perror("postmaster: StreamConnection: setsockopt");
+			perror("postmaster: StreamConnection: setsockopt(TCP_NODELAY)");
+			return STATUS_ERROR;
+		}
+		if (setsockopt(port->sock, SOL_SOCKET, SO_KEEPALIVE,
+					   &on, sizeof(on)) < 0)
+		{
+			perror("postmaster: StreamConnection: setsockopt(SO_KEEPALIVE)");
 			return STATUS_ERROR;
 		}
 	}