Ron Johnson <ron.l.johnson@cox.net> writes:
> How much does the on-disk structure of *existing* tables and indexes
> change between x.y versions?
>
> Between, for example, 8.0 and 8.2?
Enough to require a dump/reload in order to upgrade. :)
Within major versions (8.2.0, 8.2.1, etc) the files are compatible so
you can do in-place upgrades (except in extraordinary circumstances).
-Doug