Client query hangs when network connection is lost to the server.

Call me stupid if you must, but I've tried both tcp_keepalive_xxx parameters and PQcancel() to abort a query to a remote server to which I've lost the network connection with no change in results.  It appears to take about 15 minutes before the query gives up.  I assume that must be due to some other system parameter that I cannot find.  I can be very happy if I can shorten the 15 minute delay to about 30 to 60 seconds or have something else get me out the query in which I am stuck.

Specifics below.  Anything you need to know, just ask...

Thanks,
Steve


Running RedHat Enterprise Linux 5.x with PostgreSQL 8.4.


My system TCP keep alive parameters are:

My postgresql.conf file has identical parameters:



The code I used to cancel the query was:

      char errBuf[ 256 ];
      PGcancel* pgCancel = PQgetCancel( pConn );
      if( pgCancel != NULL )
      {
         int rc = PQcancel( pgCancel, errBuf, sizeof( errBuf ) );
         PQfreeCancel( pgCancel );
         cout << ": rc[" << rc << "] errBuf[" << errBuf << "]" << endl );
      }

which returned the following:


I know I have no connection!  The ping to the server failed, thus I called PQCancel() to get the query to return, so I could continue on about my business.