Data Queue Performance

[Tim Gosnell <tgosnell@xxxxxxxxxxxx>]

I have a test set up where a client application writes to a data queue
(inQueue) and reads from another one (outQueue).  I have written server
applications in both Java and Cobol (included).

I have the java client reporting the difference between
System.currentTimeMillis(); at the start and at the end of each
transactions.  I expect some variance in elapsed time reported.  The issue
here is that the variance in elapsed time is wide.  I get millisecond
reports varying from less than one millisecond all the way up the low 2000
millisecond range.   

Why would/how could the elapsed times for the transaction vary so much?
These programs caps the number of transactions at 1000.  The connections are
closed from the client.  The data being written and read in each case does
not change. 

Need help...

Cobol Code:

       ID DIVISION.
       PROGRAM-ID.  TESTDQ.
       ENVIRONMENT DIVISION.
       CONFIGURATION SECTION.
        SOURCE-COMPUTER. IBM-AS400.
        OBJECT-COMPUTER. IBM-AS400.

       DATA DIVISION.
        FILE SECTION.


        WORKING-STORAGE SECTION.

      *  COPY QUSEC OF QSYSINC-QLIBSRC.
      *  COPY QCAPCMD OF QSYSINC-QLIBSRC.
         01 IN-QUEUE-NAME       PIC X(10) VALUE "TESTINDQ".
         01 QUEUE-LIB-NAME      PIC X(10) VALUE "FOO".
         01 OUT-QUEUE-NAME      PIC X(10) VALUE "TESTOUTDQ".
         01 WAIT-TIME           PIC S9(05) VALUE -1 PACKED-DECIMAL.
         01 MSG-SIZE            PIC S9(05) VALUE 50 PACKED-DECIMAL.
         01 REQUEST             PIC X(50).
         01 RESPONSE            PIC X(50) VALUE "This is the response".
         01 INCREMENT           PIC S9(01) VALUE 1 PACKED-DECIMAL.
         01 REQUEST-NUM         PIC S9(05) VALUE 1 PACKED-DECIMAL.
         01 START-TIME          PIC S9(05).
         01 END-TIME            PIC S9(05).

        PROCEDURE DIVISION.
        MAIN.

                CALL "QRCVDTAQ" USING IN-QUEUE-NAME, QUEUE-LIB-NAME,
                                       MSG-SIZE, REQUEST, WAIT-TIME.


                CALL "QSNDDTAQ" USING OUT-QUEUE-NAME, QUEUE-LIB-NAME,
                                       MSG-SIZE, RESPONSE.

                ADD INCREMENT TO REQUEST-NUM.
           IF REQUEST-NUM = 1000 STOP RUN.
           PERFORM MAIN. 


Test Client Application Code:

package com.critrade.sandbox;

import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.Driver;
import java.sql.DriverManager;
import java.util.Properties;

import junit.framework.TestCase;

import com.ibm.as400.access.AS400;
import com.ibm.as400.access.DataQueue;
import com.ibm.as400.access.DataQueueAttributes;
import com.ibm.as400.access.DataQueueEntry;
import com.ibm.as400.access.QSYSObjectPathName;

/**
 * @author TimG
 *
 */
public class TestDTAQClient extends TestCase
{

    static final int WAIT_TIME = -1;

        DataQueue inQueue = null;
        DataQueue outQueue = null;
        AS400 host = null;
        QSYSObjectPathName inQueuePath = null;
        QSYSObjectPathName outQueuePath = null;
      Connection con = null;
      CallableStatement cs = null;
    
      String entry = "new test entry - new test entry - new test entry";
    
        public TestDTAQClient(String myName)
        {
                super(myName);

        }

        public static void main(String[] args)
        {
        junit.textui.TestRunner.run(new TestDTAQClient("testTransaction"));
        }

        protected void setUp() throws Exception
        {
                System.out.println("Establishing Database Connection");
                host = new AS400("128.128.2.220", "foo", "bar");
                DataQueueAttributes dtaqAttrib = new DataQueueAttributes();
                try
                {
                        inQueuePath = new QSYSObjectPathName("foo",
"testindq", "dtaq");
                        
                        inQueue = new DataQueue(host,
inQueuePath.getPath());
                        if(!inQueue.exists()) 
                inQueue.create(dtaqAttrib);

                }
                catch (Exception e)
                {
                        e.printStackTrace();
                }
        try
        {
            outQueuePath =
                new QSYSObjectPathName("foo", "testoutdq", "dtaq");
            outQueue = new DataQueue(host, outQueuePath.getPath());
            if(!outQueue.exists())
                outQueue.create(dtaqAttrib);
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }

        }

        protected void tearDown()
        {
                try
                {
            if(con!=null){con.close();}
                }
                catch (Exception ex)
                {
                        System.out.println(ex.getMessage());
                }
        }
    
        public void testInQueueWrite()
        {
                try
                {
                        inQueue.write(entry);
                }
                catch (Exception e)
                {
                        e.printStackTrace();
                }

    }
    
    public void testOutQueueRead()
    {
        try
        {
            DataQueueEntry entry = outQueue.read(WAIT_TIME);
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }
    
    public void testTransaction()
    {
        
        for(int i = 0; i < 1000; i++)
        {
                        
            long start = System.currentTimeMillis();
            testInQueueWrite();
            testOutQueueRead();
            long end = System.currentTimeMillis();
            System.out.println("" + (end - start));
        }
    }
}


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