"Subramanian,Ramachandran" <ramachandran.subramanian@alte-leipziger.de> writes:
> we are not doing an inplace upgrade using the pg_upgrade. Our Linux Admin tells us that the image he downloads is
fromREDHAT and not from POSTGRES and it allows only one version of Postgres to be installed at any given time.
It's been a dozen years since I worked on Red Hat's RPMs, but my
recollection is that (a) indeed, you can have only one set of
Postgres RPMs installed at a time, but (b) the version-N RPMs
include a "postgresql-upgrade" sub-package that contains a
version N-minus-1 server, and by installing that and following
its directions you could do an in-place upgrade from N-1 to N.
You'd have to do that twice to get from v16 to v18.
It's possible that they redesigned that since I was there.
Something using the "alternatives" infrastructure would be
more flexible.
regards, tom lane
