Re: pg_upgrade: How to deal with toast

Zdenek Kotala wrote:
> The question is if we should do toast modification now to avoid
> potential future problems or if we will solve it when any on-disk format
> change requires it?

Perhaps we should just add the new attid attribute to the toast table,
but mark it as nullable? We wouldn't need to fill it in in the 8.3->8.4
conversion but new tuples would include it.

In the future release that we actually need it, we'll make it
non-nullable, and write a pre-upgrade script to retoast tuples that
don't have it yet.

Hmm. That would change TOAST_MAX_CHUNK_SIZE, though.

> I prefer do it now, because there could be small risk that it will not
> possible to do it in the future. When in-place upgrade will be
> implemented nobody will want to perform backup/restore.

I feel we should avoid doing anything extra, risking that we get nothing
finished.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com