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Re: WIP: generalized index constraints

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jeff Davis <pgsql@j-davis.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Brendan Jurd <direvus@gmail.com>, Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>, pgsql-hackers@postgresql.org
Date: 2009-09-15T18:49:03Z
Lists: pgsql-hackers 
Jeff Davis <pgsql@j-davis.com> writes:
> On Tue, 2009-09-15 at 13:16 -0400, Robert Haas wrote:
>> Uhh.... so what happens if I create an index constraint using the
>> +(integer, integer) operator?

> You can use any operator that has an index search strategy. Overlaps is
> probably the most useful, but you could imagine other operators, like a
> bi-directional containment operator (either LHS is contained in RHS, or
> vice-versa).

Does it behave sanely for operators that are non-commutative, such
as '>'?  (I'm not even very sure that I know what "sanely" would be
in such a case.)

			regards, tom lane