Re: Do we still need constraint_exclusion?

On Wed, Jan 7, 2009 at 5:46 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Bruce Momjian <bruce@momjian.us> writes:
>>> * Simon Riggs (simon@2ndQuadrant.com) wrote:
>>>> I don't really understand this. Who can set up an inherited table
>>>> structure but can't remember to turn on constraint_exclusion?
>
>> This new change also adds the constraint exclusion overhead only for
>> inhertance (by default) so it should slightly improve query peformance.
>
> Right, I think that's the real winning argument for having this: it
> gets the benefit of c_e for partitioned tables without imposing overhead
> for non-partitioned tables.  See Josh B's remarks upthread about
> actually going to the trouble of turning c_e off and on on-the-fly to
> try to approximate that result.
>

what i still doesn't understand is why we need a third value at all?
why we simply can't make the new 'partition' behaviour be the default
for c_e on?

--
Atentamente,
Jaime Casanova
Soporte y capacitación de PostgreSQL
Asesoría y desarrollo de sistemas
Guayaquil - Ecuador
Cel. +59387171157