I think this documentation change:
+ leaving the old cluster untouched. At present, this is supported on Linux
---------
would be better by changing "untouched" to "unmodified".
Also, it would be nice if users could easily know if pg_upgrade is going
to use COW or not because it might affect whether they choose --link or
not. Right now it seems unclear how a user would know. Can we have
pg_upgrade --check perhaps output something. Can we also have the
pg_upgrade status display indicate that too, e.g. change
Copying user relation files
to
Copying (copy-on-write) user relation files
--
Bruce Momjian <bruce@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 +
