Re: High CPU usage after partitioning

On 01/22/2013 09:21 AM, rudi wrote:
> On Tue, Jan 22, 2013 at 3:04 PM, Merlin Moncure <mmoncure@gmail.com
> <mailto:mmoncure@gmail.com>> wrote:
>
>     let's see the query -- it's probably written in such a way so as to
>     not be able to be optimized through CE.
>
>
> The query is pretty simple and standard, the behaviour (and the plan)
> is totally different when it comes to a partitioned table.
>
> Partioned table query => explain analyze SELECT  "sb_logs".* FROM
> "sb_logs"  WHERE (device_id = 901 AND date_taken = (SELECT
> MAX(date_taken) FROM sb_logs WHERE device_id = 901));
>

And there you have it. Constraint exclusion does not work in cases like
this. It only works with static expressions (such as a literal date in
this case).

cheers

andrew