Re: Partial Indices vs. mixing columns and functions - Mailing list pgsql-general

From Tom Lane
Subject Re: Partial Indices vs. mixing columns and functions
Date
Msg-id 22179.995334332@sss.pgh.pa.us
Whole thread Raw
In response to Re: Partial Indices vs. mixing columns and functions  (Hiroshi Inoue <Inoue@tpf.co.jp>)
Responses Re: Partial Indices vs. mixing columns and functions  (Martijn van Oosterhout <kleptog@svana.org>)
List pgsql-general
Hiroshi Inoue <Inoue@tpf.co.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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