Database Software

All,

I am doing a performance test on Oracle 11g Spatial. I am simulating doing searches in 10 degree by 10 degree windows over 6M+ images, six arc minutes per side. Here is my spatial query construction:

String intersectSQL = "SELECT A.name, A.GEOMETRY.Get_WKT() " +
"FROM six_amin_polygons A " +
"WHERE SDO_RELATE(A.GEOMETRY,?, " +
"'mask=inside+coveredby+overlapbdyintersect')='TRUE'";

where the question mark is replaced by the geometry structure of the search window. The results for the first few searches are fast, then the query times balloon very quickly. PostGIS/PostgreSQL performs these searches in an average time of 30 s per window.

Here are the initial (first four rows) of Oracle Spatial results:
area_idx area_name sql_query_time number_results
0 S80.0W90.0 3890 10100
1 S80.0W80.0 3124 10100
2 S80.0W70.0 186484 10100
3 S80.0W60.0 183077 10100

Any ideas? Am I using the best mask for image/area intersection? Please advise.

Thanks,

Jeff