ORA-00023: session references process private memory; cannot detach session
 *Cause:  An attempt was made to detach the current session when it contains
          references to process private memory.
 *Action: A session may contain references to process memory (PGA) if it has
          an open network connection, a very large context area, or operating
          system privileges.  To allow the detach, it may be necessary to
          close the session's database links and/or cursors.  Detaching a
          session with operating system privileges is always disallowed.