Calling sdo_aggr_union(SDOAGGRTYPE(geoloc,0.05)) fails with following error-

ORA-07445: exception encountered: core dump [ACCESS_VIOLATION] [mdagun_iter+957] [PC:0x34BF5B3] [ADDR:0x4] [UNABLE_TO_READ] []

----CAUSE

The ORA-7445 error is most likely caused due to the invalid data in the table. To check this run -

SQL> select rowid, sdo_geom.validate_geometry_with_context(a.geoloc, .05) from test_case a;

All valid geometries should return "TRUE".

-----SOLUTION

If there are any invalid geometries in the table then manually fix them and make sure they are valid. If the invalid geometry is not needed anymore then it can be manually removed, e.g.-

SQL> delete from test_case where rowid='AAAXYgAAFAAAFzsAAA';
SQL> commit;

Now sdo_aggr_union query should work fine -

SQL> select sdo_aggr_union(SDOAGGRTYPE(geoloc,0.05)) geoloc from test_case;