Spatial Performance with join

Question

I have a Oracle Spatial table with 3.5 million rows plus another auxillary table with 3.5 million rows. A query over these two tables joined returns a full result (250 rows) based on one to one join - here's an example:
Select count(*)
from F, N
where F.id = n.id and (F.GEOM,mdsys.sdo_geometry (2003,8307, null, mdsys.sdo_elem_info_array (1,1003,1), mdsys.sdo_ordinate_array(-120.0,49.5,-119.0,49.5,-119.0,60.35,-120.0,60.35,-120.0,49.5)),
'mask= ANYINTERACT querytype=WINDOW') = 'TRUE') AND N.PNUM = '4';
It takes an average of 35 seconds to get the full result set back. I've gathered statistics, tweaked memory parameters and this is the best I can get. Does anyone have any suggestions?

Answer 1

This is an interesting problem. It looks like Oracle is doing the right thing for each of the table accesses - use the index and fetch by rowid.
The only thing you have to play with if you don't go to materialized views or temp tables is how the results of the two table queries are joined.
You don't have a lot of options. Hash join seems to be slow, but you don't know if it is faster or slower compared with nested loops or merge join.
I'd compare what you have done with something like the following to test nested loops:
select /*+ no_merge use_nl (f1,n1) */ count(*)
from
(select id
from f
where sdo_anyinteract ( F.GEOM,
sdo_geometry (2003,8307, null, sdo_elem_info_array (1,1003,1),
sdo_ordinate_array (-120.0,49.5,-119.0,49.5,-119.0,60.35,
-120.0,60.35,-120.0,49.5))) = 'TRUE') f1,
(select id
from n
where n.pnum='4') n1
where f1.id=n1.id ;
and presort with a merge join hint to see how it performs:
select /*+ no_merge use_merge (f1,n1) */ count(*)
from
(select id
from f
where sdo_anyinteract ( F.GEOM,
sdo_geometry (2003,8307, null, sdo_elem_info_array (1,1003,1),
sdo_ordinate_array (-120.0,49.5,-119.0,49.5,-119.0,60.35,
-120.0,60.35,-120.0,49.5))) = 'TRUE'
order by id) f1,
(select id
from n
where n.pnum='4'
order by id) n1
where f1.id=n1.id ;
It might be that you already have the best Oracle can do, but I'd be curious to know how you make out.
Dan Abugov
VP Software Support and Services
Acquis Inc.