Re: How to upgrade postgres 8.4 -> 9.1 contrib? - Mailing list pgsql-general

Benedikt Grundmann <bgrundmann@janestreet.com> writes:
> What is the official guide line?

You could try (1) run the 9.0 version of the hstore install script
and then (2) do the CREATE EXTENSION FROM UNPACKAGED bit.  I'd
strongly recommend testing this procedure in a scratch copy of your
installation first, though.

In a quick look through the diffs between the 8.4 and 9.0 hstore
install scripts, it looks like this should mostly work, except that
9.0 has some new operators added to the GIST and GIN index opclasses.
If you care about whether those are indexable, you would need to
drop those opclasses (and any dependent indexes) before running
the 9.0 install script, and then recreate the indexes after.

            regards, tom lane