How to break connections TCP/IP by keepalive postg

I have a system working with the client-server structure and PostgreSQL 8.4. My problem is that if a client is editing a record and lose his connection to the server, the TCPIP connection is still considered! So, the record stay allocated for the client in my database. I need the records to be free for edit in a few minutes. Therefore I set the KEEPALIVE configuration in my "postgresql.conf":

tcp_keepalives_idle = 60 # TCP_KEEPIDLE, in seconds; 
tcp_keepalives_interval = 60 # TCP_KEEPINTVL, in seconds; 
tcp_keepalives_count  = 5 # TCP_KEEPCNT

After making these settings and restart the server the system continues to function the same way: Just breaks the connection TCPIP after two hours and then deallocates the records in PostgreSQL. I need an efficient and safe way for the PostgreSQL to understand that it has to break these connections as configured!

PostgreSQL on Windows does not support keepalive settings for one connection. It is using setsockopt(s, IPPROTO_TCP, TCP_KEEPIDLE, ...) which is IMHO Linux-specific.

You can implement a patch for Postgres so it uses SIO_KEEPALIVE_VALS. Something like this in src/backend/libpq/pqcomm.c in StreamConnection function.

{
    DWORD bytesReturned = 0;
    tcp_keepalive vals;
    vals.keepalivetime = 60*1000; /* milliseconds */
    vals.keepaliveinterval = 60*1000; /* milliseconds */
    vals.onoff = 1;
    err = WSAIoctl(
        port->sock,
        SIO_KEEPALIVE_VALS,
        (char *)&vals, sizeof(vals), NULL, 0,
        &bytesReturned, NULL, NULL);
    if (err == -1) {
        elog(LOG, "WSAIoctl(SIO_KEEPALIVE_VALS) failed: %m");
    }
}

Or you can set system-wide settings in Windows registry HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters using KeepAliveInterval and KeepAliveTime settings (count is always 10 on Windows Vista and later).