Re: [Bizgres-general] A Guide to Constraint Exclusion (

Luke Lonergan <llonergan@greenplum.com>

From: "Luke Lonergan" <llonergan@greenplum.com>
To: "Simon Riggs" <simon@2ndquadrant.com>, hannu@skype.net
Cc: "bizgres-general" <bizgres-general@pgfoundry.org>, pgsql-hackers@postgresql.org
Date: 2005-07-14T21:13:17Z
Lists: pgsql-hackers
>>> CE checks will not currently recognise STABLE functions within a query.
>>> So WHERE clauses such as
>>> DateKey > CURRENT DATE
>>> will not cause exclusion because CURRENT DATE is a STABLE function.
>>> 
>>> CE checks are not made when the parent table is involved in a join.
>> 
>> Is this also the case where parent table is inside subquery and that
>> subquery is involved in a join?
> 
> My comment was too terse. What I meant was that you can't do dynamic
> exclusion based upon the results of a join. i.e. PPUC2

Phew!  Correlated subqueries won't CE then, but the more common complex
queries will.  We'll test with some common ones soon.

- Luke