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. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly