Mdsys.sdo_relate Problem

Question

Hi!
I'va got two Tables, one of them ("kante") has a Geometry - Column in it and a Quad - Tree Index is
Created, the other one ("kabelabschnitt") is linked to "kante" via a foreign key.
This Query is very fast:
SELECT k.* FROM kante k
where sdo_relate(geom, mdsys.sdo_geometry(2003,NULL,NULL, mdsys.sdo_elem_info_array(1,1003,3), mdsys.sdo_ordinate_array(34520, 253535, 34621, 253606)), 'mask=ANYINTERACT querytype=window') = 'TRUE';
But this takes about 20 s:
SELECT k.*, ka.* FROM kante k, kabelabschnitt ka
where ka.id_ka = k.id_kante
and sdo_relate(geom, mdsys.sdo_geometry(2003,NULL,NULL, mdsys.sdo_elem_info_array(1,1003,3), mdsys.sdo_ordinate_array(34520, 253535, 34621, 253606)), 'mask=ANYINTERACT querytype=window') = 'TRUE';
Can anynone tell me why??
Thanx in advance,
J

Answer 1

Hi,
It could be slower because the optimizer is choosing to use an index associated
with the join key between the tables instead of the spatial index.
Try adding the /*+ no_index (, index_name) */ hint, i.e.
SELECT /*+ no_index (K name_of_id_kante_index) k.*, ka.*
FROM kante k, kabelabschnitt ka
where ka.id_ka = k.id_kante
and sdo_relate(geom, mdsys.sdo_geometry(2003,NULL,NULL,
mdsys.sdo_elem_info_array(1,1003,3),
mdsys.sdo_ordinate_array(34520, 253535, 34621, 253606)),
'mask=ANYINTERACT querytype=window') = 'TRUE';
Hope this helps,
Dan