Re: Materialized views WIP patch

Andres Freund <andres(at)2ndquadrant(dot)com> wrote:

> I assume that at some point matviews will get (auto-)updateable,
> just as normal views recently got.

I'm dubious about that.  Every use case I've seen for MVs involves
aggregation, although they are a generalized feature, so that won't
always be true.  But if you have a view like:

CREATE MATERIALIZED VIEW tm AS
 SELECT t.type,
    sum(t.amt) AS totamt
   FROM t
  GROUP BY t.type;

... I don't see how that can be updateable.  If I add 5 to totamt
for some row, what do you do?  I expect that 99% of MVs will be
updated asynchronously from changes to the underlying data -- what
do you do if someone updates a row that no longer exists in the
underlying data.  This are just seems fraught with peril and out of
sync with the usual uses of MVs.

> What about DISABLE? DISCARD or DEALLOCATE would also be nice but
> it seems hard to fit that into existing syntax.

Thanks for the suggestions.

--
Kevin Grittner
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