From: | Martijn van Oosterhout <kleptog(at)svana(dot)org> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | Hiroshi Inoue <Inoue(at)tpf(dot)co(dot)jp>, Mike Mascari <mascarm(at)mascari(dot)com>, pgsql-general(at)postgresql(dot)org |
Subject: | Re: Partial Indices vs. mixing columns and functions |
Date: | 2001-07-17 03:08:51 |
Message-ID: | 20010717130851.B26211@svana.org |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
On Mon, Jul 16, 2001 at 09:45:32PM -0400, Tom Lane wrote:
> (But what the planner can recognize as matching a query's
> WHERE clause is currently much more restricted, just ANDs
> and ORs of simple VAR OP CONST clauses. This could be
> improved in the future.)
I've been think about adding IS (NOT) NULL type clauses and it doesn't look
too hard but I wonder if my logic is right.
> > Both the functions used in functional indexes and the
> > predicates used in partial indexes must be deterministic.
> > Are users responsible for it ?
>
> Yes. I don't see how the system could enforce that, without
> prohibiting lots of useful cases.
>
Well, isn't there an attribute on a function that indicates whether the same
input gives the same output (cachable?). I think that's all that would be
required and not restrict any useful cases.
--
Martijn van Oosterhout <kleptog(at)svana(dot)org>
http://svana.org/kleptog/
> It would be nice if someone came up with a certification system that
> actually separated those who can barely regurgitate what they crammed over
> the last few weeks from those who command secret ninja networking powers.
From | Date | Subject | |
---|---|---|---|
Next Message | Janning Vygen | 2001-07-17 10:59:09 | Application Design and PostgreSQL |
Previous Message | Hiroshi Inoue | 2001-07-17 01:52:36 | Re: Partial Indices vs. mixing columns and functions |