PL/SQL to Java Interface - Overwhelming Overhead?

Question

My company is running Oracle 10g R2. I am currently exploring the use of java classes from PL/SQL. This is because we have multiple code bases, including Java, PowerBuilder (which can interface with Java), and PL/SQL (which can interface with Java).
Doing some performance testing, I found some rather alarming results. Running a simple java function 1 million times, I tested performance of PL./SQL to java and PowerBuilder to Java.
In PL/SQL, the 1 mil calls executed in ~120 s.
In PowerBuilder, the 1 mil calls executed in ~54 s.
Is it possible that our database is incorrectly configured for best java performance? Not only does it appear that PowerBuilder, a much less pervasive language than PL/SQL, is over twice as fast, but the PB test was run on my laptop, which is no where near as powerful as the database server that the PL/SQL procedure ran against, leading me to believe that the performance gap is actually much wider.
Anyone have any tips to improve the performance? Or is this simply the nature of the beast? I can't seem to find any posts on the net about people experiencing huge PL/SQL to Java overhead, so I'm hoping it is just something I am doing wrong.
Thanks for your help!
-Brett Birschbach

Answer 1

Below is my test code. Any suggestions are appreciated.
Thanks!
-Brett
==================================================
Java Class:
public class TestConvert {
    // For running straight from Java
    public static void main(String[] args){
        System.out.println(callAndTime());
    // For running 1 mil calls with only one call from PowerBuilder or PL/SQL
    public static long callAndTime(){
        TestConvert.convertEsnDecToHex("13005454488");
        long start = System.currentTimeMillis();
        for (int i = 0; i < 1000000; i++){
            TestConvert.convertEsnDecToHex("13005454488");
        long end = System.currentTimeMillis();
        return end-start;
    // For performing the actual work
    public static String convertEsnDecToHex(String esn) {
        String result = null;
        result = Integer.toHexString(new Integer(esn.substring(0, 3)).intValue());
        result += Integer.toHexString(new Integer(esn.substring(3)).intValue());
        return result.toUpperCase();
    // Non-static wrapper necessary for PowerBuilder
    public String callAndTimeNS(){
        return String.valueOf(callAndTime());
    // Non-static wrapper necessary for PowerBuilder 
    public String convertEsnDecToHexNS(String esn){
        return convertEsnDecToHex(esn);
}PL/SQL Script for 1 Million Java Calls:
DECLARE
  var       VARCHAR2( 20 );
  t_begin   NUMBER;
  t_end     NUMBER;
BEGIN
  var := testconvert.convertesndectohex( '13005454488' );
  t_begin := DBMS_UTILITY.get_time;
  FOR i IN 1 .. 1000000
  LOOP
    var := testconvert.convertesndectohex( '13005454488' );
  END LOOP;
  t_end := DBMS_UTILITY.get_time;
  DBMS_OUTPUT.put_line( var );
  DBMS_OUTPUT.put_line(  ( t_end - t_begin ) / 100 || ' seconds' );
END;
/PowerBuilder for 1 Million Java Calls:
EJBConnection lEJBConn
TestConvert lnv_test
String ls_ret
Long i
Time t_begin, t_end
lEJBConn = CREATE EJBConnection
lEJBConn.CreateJavaInstance( lnv_test, "TestConvert")
ls_ret = lnv_test.convertesndectohexns("13005454488")
t_begin = now()
FOR i = 1 TO 1000000          
     ls_ret = lnv_test.convertesndectohexns("13005454488")
NEXT
t_end = now()
MessageBox("Hex Version",ls_ret + " - " + String(SecondsAfter(t_begin, t_end)) + " seconds")
DESTROY lEJBConn