Urgent help (on oracle connection pool)

Question

Hi ,
I downloade oracle 8i thin drivers and i am using conenction pool in my application ...
I executed that servlet program
When i try to get conneciton using getDatabaseConnection() method in my jsp i am getting new connection each time ...............
In the oracel doc i read some thing like logical connections and physical connections .............
In my code i set maxLimit to 3 and i am getting connections more than 3 ( all are different).................
When i refresh the browser i am getting different connections like:
con======oracle.jdbc.driver.OracleConnection@338576
con======oracle.jdbc.driver.OracleConnection@1691dec
con======oracle.jdbc.driver.OracleConnection@63ceb4
con======oracle.jdbc.driver.OracleConnection@1590f50
con======oracle.jdbc.driver.OracleConnection@aeff82
con======oracle.jdbc.driver.OracleConnection@906e5b
con======oracle.jdbc.driver.OracleConnection@2403cf
con======oracle.jdbc.driver.OracleConnection@17ab157
See i set max limit as 3 and i got more than 3 connections and each diff ................
What is wrong in my code ............
Please help to me ..........
Here is the code :
import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.sql.*;
import oracle.jdbc.driver.*;
import oracle.jdbc.pool.*;
public class PoolJdbc4 extends HttpServlet{
private OracleConnectionPoolDataSource ocpds;
private OracleConnectionCacheImpl ods;
public void init(ServletConfig config) throws ServletException {
super.init(config);
try {
ocpds =new OracleConnectionPoolDataSource();
ocpds.setURL("jdbc:oracle:xxxxxxxxx");
// ocpds.setUser("xxx");
// ocpds.setPassword("xxx");
// Associate it with the Cache
ods = new OracleConnectionCacheImpl(ocpds);
// Set the Max Limit
ods.setMaxLimit (3);
// Set the Scheme
ods.setCacheScheme (OracleConnectionCacheImpl.FIXED_RETURN_NULL_SCHEME);
catch (Exception e) {
throw new UnavailableException(this, "Couldn't create connection pool");
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
Connection con = null;
res.setContentType("text/plain");
PrintWriter out = res.getWriter();
out.println("Updating salary");
try {
con = ods.getConnection("xxxxx","xxx");
System.out.println("con======="+con);
// Turn on transactions
con.setAutoCommit(false);
Statement stmt=con.createStatement();
ResultSet rs=stmt.executeQuery("select * from checkout_checkin");
while(rs.next())
out.println(rs.getString(1)+"<br>");
stmt.close();
rs.close();
con.close();
catch (Exception e) {
// Any error is grounds for rollback
try {
con.rollback();
catch (Exception ignored) { }
out.println("No more connections available, try later");
}

Answer 1

ketan reddy - I'm pretty sure you are not getting a new connection each time even though you are seeing a different connection identifier printed each time you get a new connection.
If you have system privs, try looking at v$session while your servlet is running. I think you will see that you only have a single connection and it is being used each time.
For another test, try commenting out your conn.close() call so that you do not free up connections. Your servlet should fail after 3 executions cause it will not be able to get any more connections - because you specified
ods.setMaxLimit (3);
ods.setCacheScheme (OracleConnectionCacheImpl.FIXED_RETURN_NULL_SCHEME);
Good Luck
tim