session identifier

I have applied the attached documentation patch to illustrate how to
compute the session identifier using pg_stat_activity.

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +
Index: config.sgml
===================================================================
RCS file: /cvsroot/pgsql/doc/src/sgml/config.sgml,v
retrieving revision 1.217
diff -c -r1.217 config.sgml
*** config.sgml    2 Jun 2009 17:37:55 -0000    1.217
--- config.sgml    3 Jun 2009 00:37:39 -0000
***************
*** 3088,3094 ****
           consisting of two 4-byte hexadecimal numbers (without leading zeros)
           separated by a dot.  The numbers are the process start time and the
           process ID, so <literal>%c</> can also be used as a space saving way
!          of printing those items.
         </para>

         <tip>
--- 3088,3101 ----
           consisting of two 4-byte hexadecimal numbers (without leading zeros)
           separated by a dot.  The numbers are the process start time and the
           process ID, so <literal>%c</> can also be used as a space saving way
!          of printing those items.  For example, to generate the session
!          identifier from <literal>pg_stat_activity</>, use:
! <programlisting>
! SELECT to_hex(EXTRACT(EPOCH FROM backend_start)::integer) || '.' ||
!        to_hex(procpid)
! FROM pg_stat_activity;
! </programlisting>
!
         </para>

         <tip>