Re: pg_upgrade supported versions policy

On Wed, Nov 21, 2018 at 03:47:22PM -0800, Andres Freund wrote:
> Hi,
>
> I feel like we ought to trim the support for a few old versions from
> pg_upgrade. In my particular case I don't really think it's reasonable
> to test < 9.0 versions for pg_largeobject_metadata migrations. But I
> think we should create a policy that's the default, leaving individual
> cases aside.
>
> I can see a few possible policies:
>
> 1) Support upgrading from the set of releases that were supported when
> the pg_upgrade target version was released. While some will argue that
> this is fairly short, people above it can still upgrade ~10 years
> worth of versions with a single intermediary upgrade.
> 2) Same, but +2 releases or such.
> 3) Support until it gets too uncomfortable.
> 4) Support all versions remotely feasible (i.e. don't drop versions that
> still can be compiled)

The way pg_upgrade works right now, 1), 2), and 4) basically make it
impossible to change our storage format in any non-trivial way, and 3)
is a "trivial case" in the sense that the first such non-trivial
storage format change ends pg_upgrade support.

Are we really that attached to how we store things?

Best,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778

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