Re: Partitioning and constraint exclusion

On Mon, Sep 7, 2015 at 4:48 PM, David G. Johnston <
david(dot)g(dot)johnston(at)gmail(dot)com> wrote:

> IIRC ​The planner doesn't understand​
>
> ​overlaps so having a definition of:
>
> IN (1,2,3,4,5); or nearly equivalently = ANY(ARRAY[1,2,3,4,5]))​
>
> and a request for:
>
> IN (1,3,5) / = ANY(ARRAY[1,3,5]) is going to get you nowhere with the
> planner.
>

The partition code does not execute your CHECK condition; it only tests to
see if the query includes it explicitly. For example, if you have a split
on "id % 100 = 59" for a table, then looking for id = 13059 does you no
good; you have to search for "id = 13059 AND id % 100 = 59" to invoke the
table exclusions.