Re: partition queries hitting all partitions even though check key is specified - Mailing list pgsql-performance

On Wed, 2009-09-02 at 09:39 -0600, Kevin Kempter wrote:

> >
> > You sure you remembered those fiddly little casts everywhere?
> > (Frankly, declaring "time" as integer and not timestamp here strikes
> > me as utter lunacy.)  What PG version are you using?
> >
> >             regards, tom lane
>

As far as I know constraint exclusion doesn't work with date_part or
extract().

The following caveats apply to constraint exclusion:

      * Constraint exclusion only works when the query's WHERE clause
        contains constants. A parameterized query will not be optimized,
        since the planner cannot know which partitions the parameter
        value might select at run time. For the same reason, "stable"
        functions such as CURRENT_DATE must be avoided.

http://www.postgresql.org/docs/8.3/static/ddl-partitioning.html

Or did I miss something?

Joshua D. Drake

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