| From: | "Luke Lonergan" <llonergan(at)greenplum(dot)com> |
|---|---|
| To: | "Simon Riggs" <simon(at)2ndquadrant(dot)com>, hannu(at)skype(dot)net |
| Cc: | "bizgres-general" <bizgres-general(at)pgfoundry(dot)org>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: [Bizgres-general] A Guide to Constraint Exclusion ( |
| Date: | 2005-07-14 21:13:17 |
| Message-ID: | BEFC237D.8B4A%llonergan@greenplum.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| 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
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