On Fri, May 20, 2016 at 07:40:53PM -0400, Robert Haas wrote: > On Mon, May 16, 2016 at 3:36 AM, Bruce Momjian <br...@momjian.us> wrote: > > On Sun, May 15, 2016 at 03:23:52PM -0500, Jim Nasby wrote: > >> 2) There's no ability at all to revert, other than restore a backup. That > >> means if you pull the trigger and discover some major performance problem, > >> you have no choice but to deal with it (you can't switch back to the old > >> version without losing data). > > > > In --link mode only > > No, not really. Once you let write transactions into the new cluster, > there's no way to get back to the old server version no matter which > option you used.
Yes, there is, and it is documented: If you ran <command>pg_upgrade</command> <emphasis>without</> <option>--link</> or did not start the new server, the old cluster was not modified except that, if linking started, a <literal>.old</> suffix was appended to <filename>$PGDATA/global/pg_control</>. To reuse the old cluster, possibly remove the <filename>.old</> suffix from <filename>$PGDATA/global/pg_control</>; you can then restart the old cluster. What is confusing you? -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + As you are, so once was I. As I am, so you will be. + + Ancient Roman grave inscription + -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers