Using pg_upgrade on log-shipping standby servers

I occasionally get questions about how to run pg_upgrade on log-shipping
standby servers.  The attached documentation patch outlines how to do
it.

I don't think we can assume that because pg_upgrade was run on the
master and standby that they are binary identical, can we?  Technically
the user file are identical, but the system catalogs and WAL might be
different, hence my suggestion to run rsync before allowing the standby
to rejoin the primary.

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

  + It's impossible for everything to be true. +