I've been having a look at this guy, trying to get a handle on how much
down time it will save.
As a quick check, I tried upgrading a cluster with a 1 non default db
containing a scale 100 pgbench schema:
- pg_upgrade : 57 s
- pgdump/pg_restore : 154 s
So, a reasonable saving all up - but I guess still a sizable chunk of
downtime in the case of a big database to copy the user relation files.
I notice there is a "link" option that would be quicker I guess - would
it make sense to have a "move" option too? (perhaps with pg_upgrade
writing an "un-move" script to move them back just in case).
Regards
Mark