[postgis-users] 3D index in postgis

[Paul Ramsey]

On Tue, May 20, 2008 at 8:40 AM, Kevin Neufeld <kneufeld at refractions.net> wrote:
>
> a1001800 wrote:
>> Thanks Kevin,
>>
>> It looks like ~= not invoke the index.
>
> That's why I suggested the && operator as well.  It does use the index.
>
>> Do we have a way to deal with an index with third value?
>> For example, point (x, y) and userid
>>
>> I need to do a query like "select point(x,y) from table where point in
>> rectangle and userid=xxx"
>
> Sure.  Add the userid=xxx to your filter list like you were doing.
> ie.
> SELECT ST_MakePoint(x,y)
> FROM mytable
> WHERE geom && <insert rectangle geom here>
> AND userid = xxx;
>
> You can additionally add an ST_Contains() filter if you need to have
> your points exactly inside the rectangle.

No, don't do that :)  "point && rectangle" is logically the same as
"st_contains(rectangle, point)" and somewhat cheaper.

The key is knowing for 100% sure that your polygonal geometry will
*always* be a rectangle. If there's a chance it won't, you need the
st_contains.

P