Tom Lane wrote: > Richard Huxton <dev@archonet.com> writes: > > Might it be possible to apply rule-style rewriting to a clause of an > > ordinary select query? That is, is it prohibitively expensive to get PG > > to recognise > > SELECT count(*) FROM big_table > > and replace it with > > SELECT sum(summary_count) FROM my_materialised_view > > > This should allow you to have where-clauses and apply to a range of > > cases. What I fear is that checking to see if the rule applies will cost > > too much on all those queries where it doesn't apply. > > There is already code in the optimizer that does similar rewriting > for min/max queries. However, that's a hard-wired transformation. > I don't see any very simple way to provide a user-configurable > equivalent.
I guess there must be a query-rewriting mechanism for implementing materialized views. With that in place we may be able to implement this other thing ... Is anybody working on materialized views? -- Alvaro Herrera http://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
