>> Hopefully the grouping of tables is not purely related to AV?
>
> Hmm, good question. I was envisioning it only for autovacuum, but it
> hasn't been vetted on pgsql-hackers.
I think we're in danger of inventing a solution in search of a problem here.
AIUI, the main reason for table groups would be to define different
autovacuum policies for different groups of tables. Right now, that
would be pretty stupid, because there are only two possible policies:
"yes" and "no". But if the policy is something very complex, then
you're not going to want to redefine it for each individual table.
Instead, you're going to want to define it once and then point
individual tables at it. But you could do that just as well by
assigning each policy a name or number and then setting a reloption on
the table to refer to that name or number, which would completely
avoid the need to invent all-new, non-standard syntax.
But if we do decide to invent such a syntax, it's not good enough to
say that we should make it general because it might be useful for a
purpose other than autovacuum. We should have a pretty specific idea
of what sort of purpose that might be. Otherwise, we'll likely find
(when the purpose finally arises) that the supposedly-general model we
introduced doesn't fit it as well as we thought.
But right now, we don't even have ONE use case for the general syntax,
let alone two, because the future autovacuum enhancements that would
make use of that syntax haven't been designed yet (or at least haven't
been discussed here yet).
...Robert
