SQLException during stress test

[kakkodi]

During stress tests with large number of concurrent users (50-100)

I get SQLException below after user count reach a certain number. This happens intermittently.

Could this be because connections could not be opened at the database end in quick intervals? or is there a configuration that need to looked at?


2005-07-06 14:02:45,506 WARN [org.jboss.resource.connectionmanager.JBossManagedConnectionPool] Throwable while attempting to get a new connection: null
org.jboss.resource.JBossResourceException: Could not create connection; - nested throwable: (java.sql.SQLException: Io exception: The Network Adapter could not establish the connection)


The application is a simple struts application querying a table in oracle 9i database. Jboss 4.0.1 is running on Windows 2000

Application code that make database query is listed below



public List getAllCDES(String longName) throws Exception
{
Connection conn = null;
Statement st =null;
ResultSet rs = null;
List list = new ArrayList();
try
{
conn = SimpleDAOImpl.getConnectionFromContainer("java:comp/env/jdbc/CDEBrowserDS");
//Statement st = conn.
String sqlStmt = "SELECT * FROM data_elements_view "
+"WHERE long_name like '"+longName+"'";

st = conn.createStatement();
rs = st.executeQuery(sqlStmt);

while(rs.next())
{
DataElement de = new DataElement();
de.setLongName(rs.getString("long_name"));
de.setPublicId(rs.getString("cde_id"));
list.add(de);
}

}

catch (Exception e)
{
System.out.println("Exception while getting CDEs");
throw e;
}
finally
{
if(st!=null)
try
{
st.close();
}
catch (Exception ex)
{
System.out.println("Exception while Closing st");
}
if(rs!=null)
try
{
rs.close();
}
catch (Exception exp)
{
System.out.println("Exception while Closing rs");
}
if(conn!=null)
try
{
conn.close();
System.out.println("Connection Closed");
}
catch (Exception ecexp)
{
System.out.println("Exception while Closing Connection");
}
}
return list;

}

public static Connection getConnectionFromContainer(String dataSourceName)
throws NamingException,Exception {

Connection conn = null;
try {
InitialContext ic = new InitialContext();
DataSource ds = (DataSource)ic.lookup(dataSourceName);
conn = ds.getConnection();

System.out.println("Connected to the database successfully using datasource "+dataSourceName);
}
catch (NamingException ne) {
System.out.println("Exception occurred in getConnectionFromContainer for DataSource name="+dataSourceName);
throw new NamingException
("Failed to lookup JDBC datasource. Check the datasource name");
}
catch (Exception e) {
System.out.println("Exception occurred in getConnectionFromContainer");
throw new Exception("Exception in getConnectionFromContainer() ");
}
return conn;
}

Below is the oracle-ds.xml entry


<local-tx-datasource>
<jndi-name>jdbc/CDEBrowserDS</jndi-name>
<connection-url>jdbc:oracle:thin:@myhost:1521:dev</connection-url>
<driver-class>oracle.jdbc.driver.OracleDriver</driver-class>
<user-name>user</user-name>
mypassword
<exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.OracleExceptionSorter</exception-sorter-class-name>
<blocking-timeout-millis>0</blocking-timeout-millis>
<idle-timeout-minutes>1</idle-timeout-minutes>
<max-pool-size>100</max-pool-size>
<min-pool-size>0</min-pool-size>
</local-tx-datasource>

Thanks
-Shaji