Slow performance when using cursor with bind variable

Question

i'm facing the problem mentioned in the subject.
whenever i use the bind variable it would take more than 5mins to fetch 157 records, but if i hardcode the value ( not using variable ) it would take only 10sec to fetch 157 records.
can anyone give me some guide to solve this problem? thank you..
Code :
DECLARE
cursor cur1(l_startdate IN varchar2,l_enddate IN varchar2) IS
select * from shipment ship where ship.insertion_date >= to_date(l_startdate,'DD-MM-YYYY HH24:MI:SS') and ship.insertion_date < to_date(l_enddate ,'DD-MM-YYYY HH24:MI:SS')
TYPE shipment_aat IS TABLE OF cur1%ROWTYPE INDEX BY PLS_INTEGER;
l_shpt shipment_aat;
limit_in INTEGER := 100;
BEGIN
v_startdate := '10-06-2008 14:00:00';
v_enddate := '10-06-2008 17:00:00';
OPEN C_shpt(v_startdate,v_enddate);
LOOP --start shipment loop   
FETCH C_shpt BULK COLLECT INTO l_shpt LIMIT limit_in;
     FOR indx IN 1 .. l_shpt.COUNT
LOOP
DBMS_OUTPUT.PUT_LINE('l_shpt value ' || l_shpt(indx).ship_number || '/' || l_shpt(indx).insertion_date);
END LOOP;
EXIT WHEN l_shpt.COUNT < limit_in;
END LOOP; -- end of shipment loop
CLOSE cur1;
END;

Answer 1

When your query takes too long ...