Performance Tuning :: How To Show Right IO Of Query

I use oracle 11g r2

i have created a table for objects

create table table_t
(Record_no number,
t_no number,
position SDO_GEOMETRY
, occupation_time number);

and inserted many values (examples below )

INSERT INTO tra VALUES
(2,
20503,
SDO_GEOMETRY
(2001,
NULL,
SDO_POINT_TYPE (1387, 0, NULL),
NULL,
NULL),
23037
)
/

and( position) indexed as Rtree spatial index

now when i run spatial query such as

SELECT * FROM tra t WHERE
SDO_FILTER(t.position, MDSYS.SDO_GEOMETRY(2001,NULL,NULL, MDSYS.SDO_ELEM_INFO_ARRAY(1,1003,3),
MDSYS.SDO_ORDINATE_ARRAY(0,0,9000,0)), 'querytype=WINDOW') = 'TRUE' and t.position.sdo_point.X=1;

i do not know how many IO accrued ?

i tried set autotrace on

but the physical read is 0 , this is not possible because i have more than 100000 objects there and all indexed as R-tree