Re: Functional dependencies and GROUP BY

On Tue, Jun 8, 2010 at 3:05 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Well, no, any cached plan will get invalidated if the index goes away.
> The big problem with this implementation is that you could create a
> *rule* (eg a view) containing a query whose validity depends on the
> existence of an index.  Dropping the index will not cause the rule
> to be invalidated.

Hm, I was incorrectly thinking of this as analogous to the cases of
plans that could be optimized based on the existence of a constraint.
For example removing columns from a sort key because they're unique.
But this is different because not just the plan but the validity of
the query itself is dependent on the constraint.

--
greg