| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Hiroshi Inoue <Inoue(at)tpf(dot)co(dot)jp> |
| Cc: | Mike Mascari <mascarm(at)mascari(dot)com>, Martijn van Oosterhout <kleptog(at)svana(dot)org>, pgsql-general(at)postgresql(dot)org |
| Subject: | Re: Partial Indices vs. mixing columns and functions |
| Date: | 2001-07-17 01:45:32 |
| Message-ID: | 22179.995334332@sss.pgh.pa.us |
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| Lists: | pgsql-general |
Hiroshi Inoue <Inoue(at)tpf(dot)co(dot)jp> writes:
> What kind of expression is allowed as the predicate now ?
Anything that doesn't involve an aggregate or a subselect.
(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.)
> 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.
regards, tom lane
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