Connection Pooling in a JAAS Provider

What is the recommended way of doing resource pooling inside of a JAAS provider?
I'm trying to use a DataSource inside of my providers (my realm uses an Oracle
database), but, of course, WebLogic want's to check access for the DataSource
=> infinite loop.
Has anyone run into this and found a good way around?
Thanks.
--Kevin

If you read the JavaServer Pages specification, you will realize that there is provision for such things.
The following is an extract from the JavaServer Pages specification 1.1...
The contract also describes how a JSP author can indicate that some actions must be taken
when the init() and destroy() methods of the page implementation occur. In JSP 1.1 this is
done by defining methods with name jspInit() and jspDestroy() in a declaration scripting
element in the JSP page. Before the first time a request is delivered to a JSP page a jspInit()
method, if present, will be called to prepare the page. Similarly, a JSP container can reclaim
the resources used by a JSP page at any time that a request is not being serviced by the JSP
page by invoking first its jspDestroy() method, if present.
So, you should dfine a method with the signature public void jspInit() in your JSP and do the one time initialization therein. Also, you do the associated cleanup in a method with the signature public void jspDestroy()

Similar Messages

Shared Connection Pool via Singleton

I have just started to learn Java (more jsp & servlets) and have been going through "Core Servlets and Java Server Pages" and in there is stuff on connection pooling. The author provides a good a connection pool servlet that can be shared, but as I'm new and don't fully understand how everything works (got a basic idea).
How do i go about making the following code accessiable via a singleton class?
ConnectionPool Class
package sco;
import java.sql.*;
import java.util.*;
/** A class for preallocating, recycling, and managing
* JDBC connections.
* 
* Taken from Core Servlets and JavaServer Pages
* from Prentice Hall and Sun Microsystems Press,
* http://www.coreservlets.com/.
* © 2000 Marty Hall; may be freely used or adapted.
public class ConnectionPool implements Runnable {
private String driver, url, username, password;
private int maxConnections;
private boolean waitIfBusy;
private Vector availableConnections, busyConnections;
private boolean connectionPending = false;
public ConnectionPool(String driver, String url,
 String username, String password,
 int initialConnections,
 int maxConnections,
 boolean waitIfBusy)
 throws SQLException {
 this.driver = driver;
 this.url = url;
 this.username = username;
 this.password = password;
 this.maxConnections = maxConnections;
 this.waitIfBusy = waitIfBusy;
 if (initialConnections > maxConnections) {
 initialConnections = maxConnections;
 availableConnections = new Vector(initialConnections);
 busyConnections = new Vector();
 for(int i=0; i<initialConnections; i++) {
 availableConnections.addElement(makeNewConnection());
public synchronized Connection getConnection()
 throws SQLException {
 if (!availableConnections.isEmpty()) {
 Connection existingConnection =
 (Connection)availableConnections.lastElement();
 int lastIndex = availableConnections.size() - 1;
 availableConnections.removeElementAt(lastIndex);
 // If connection on available list is closed (e.g.,
 // it timed out), then remove it from available list
 // and repeat the process of obtaining a connection.
 // Also wake up threads that were waiting for a
 // connection because maxConnection limit was reached.
 if (existingConnection.isClosed()) {
 notifyAll(); // Freed up a spot for anybody waiting
 return(getConnection());
 } else {
 busyConnections.addElement(existingConnection);
 return(existingConnection);
 } else {
 // Three possible cases:
 // 1) You haven't reached maxConnections limit. So
 // establish one in the background if there isn't
 // already one pending, then wait for
 // the next available connection (whether or not
 // it was the newly established one).
 // 2) You reached maxConnections limit and waitIfBusy
 // flag is false. Throw SQLException in such a case.
 // 3) You reached maxConnections limit and waitIfBusy
 // flag is true. Then do the same thing as in second
 // part of step 1: wait for next available connection.
 if ((totalConnections() < maxConnections) &&
 !connectionPending) {
 makeBackgroundConnection();
 } else if (!waitIfBusy) {
 throw new SQLException("Connection limit reached");
 // Wait for either a new connection to be established
 // (if you called makeBackgroundConnection) or for
 // an existing connection to be freed up.
 try {
 wait();
 } catch(InterruptedException ie) {}
 // Someone freed up a connection, so try again.
 return(getConnection());
// You can't just make a new connection in the foreground
// when none are available, since this can take several
// seconds with a slow network connection. Instead,
// start a thread that establishes a new connection,
// then wait. You get woken up either when the new connection
// is established or if someone finishes with an existing
// connection.
private void makeBackgroundConnection() {
 connectionPending = true;
 try {
 Thread connectThread = new Thread(this);
 connectThread.start();
 } catch(OutOfMemoryError oome) {
 // Give up on new connection
public void run() {
 try {
 Connection connection = makeNewConnection();
 synchronized(this) {
 availableConnections.addElement(connection);
 connectionPending = false;
 notifyAll();
 } catch(Exception e) { // SQLException or OutOfMemory
 // Give up on new connection and wait for existing one
 // to free up.
// This explicitly makes a new connection. Called in
// the foreground when initializing the ConnectionPool,
// and called in the background when running.
private Connection makeNewConnection()
 throws SQLException {
 try {
 // Load database driver if not already loaded
 Class.forName(driver);
 // Establish network connection to database
 Connection connection =
 DriverManager.getConnection(url, username, password);
 return(connection);
 } catch(ClassNotFoundException cnfe) {
 // Simplify try/catch blocks of people using this by
 // throwing only one exception type.
 throw new SQLException("Can't find class for driver: " +
 driver);
public synchronized void free(Connection connection) {
 busyConnections.removeElement(connection);
 availableConnections.addElement(connection);
 // Wake up threads that are waiting for a connection
 notifyAll();
public synchronized int totalConnections() {
 return(availableConnections.size() +
 busyConnections.size());
/** Close all the connections. Use with caution:
 * be sure no connections are in use before
 * calling. Note that you are not required to
 * call this when done with a ConnectionPool, since
 * connections are guaranteed to be closed when
 * garbage collected. But this method gives more control
 * regarding when the connections are closed.
public synchronized void closeAllConnections() {
 closeConnections(availableConnections);
 availableConnections = new Vector();
 closeConnections(busyConnections);
 busyConnections = new Vector();
private void closeConnections(Vector connections) {
 try {
 for(int i=0; i<connections.size(); i++) {
 Connection connection =
 (Connection)connections.elementAt(i);
 if (!connection.isClosed()) {
 connection.close();
 } catch(SQLException sqle) {
 // Ignore errors; garbage collect anyhow
public synchronized String toString() {
 String info =
 "ConnectionPool(" + url + "," + username + ")\n" +
 ", available=" + availableConnections.size() + "\n" +
 ", busy=" + busyConnections.size() + "\n" +
 ", max=" + maxConnections;
 return(info);
ScoPool Class (singleton to access the connection pool)
package sco;
public class ScoPool extends ConnectionPool {
private ScoPool pool = null;
private ScoPool() {
 super(); // Call parent constructor
public static synchronized ScoPool getInstance() {
 if(pool == null) {
 pool = new ScoPool();
 return(pool);
}Please help a newbie.

Figured it out.
package sco;
import java.sql.SQLException;
public class ScoPool extends ConnectionPool {
private static ScoPool pool;
private ScoPool(String driver, String url, String username, String password,
 int initialConnections, int maxConnections, boolean waitIfBusy) throws SQLException {
 super(driver, url, username, password, initialConnections, maxConnections, waitIfBusy); // Call parent constructor
public static synchronized ScoPool getInstance() {
 if(pool == null) {
 String driver = "com.microsoft.jdbc.sqlserver.SQLServerDriver";
 String url = "jdbc:microsoft:sqlserver://MIM-W0432:1433;DatabaseName=sco";
 String username = "sco_user";
 String password = "123";
 int initCon = 5;
 int maxCon = 10;
 boolean waitIfBusy = true;
 try {
 pool = new ScoPool(driver, url, username, password, initCon, maxCon, waitIfBusy);
 catch(SQLException sqle) {
 return pool;
}

Questions regarding Connection Pooling

Hi
i have some confusion regarding how connection pooling is implemented..i have been doing some digging in to this lately but the more i read the more confused i get. i have some doubts here, will any of the posters here kindly clear them
a. Do i have to connect to my database via the DataSource method to take advantage of the connection pooling provided by my app server?..i have read conflicting information about this suggesting that Connection Pooling will not be provided to my app if i use DriverManager.getConnection()
b. if i chose to use the DataSource method do i have to implement the ConnectionPoolDataSource interface to provide the connection pooling for my app?
c. what is the best way to implement my own custom Connection pool?
Thanx

DriverManager.getConnection() literally creates, that is, builds a connection to the database using the values you previously supplied when you loaded the driver.
A connection pool is an object that contains several already made connections to the database, and simply provides you with one of those existing connections. The confusion arises because a) the method name is frequently the same and b) the connection pool object calls the driver's getConnection() method to create several connections before lending any of them out.
In other words:
DriverManager.getConnection() builds a connection to the database.
ConnectionPool.getConnection() fetches an existing connection.
So, to answer your questions...
A. This is correct. If you use DriverManager.getConnection(), you are indeed bypassing the Connection Pool entirely.
B. I'm not familiar with DataSource specifically, but in general, a third party connection pool will either give you the interface (and you implement the details) or they will give you the class file containing the DataSource object. All you would have to do in the latter case is to import that file, then create a new instance of it using the new keyword ( DataSource foo = new DataSource(); ). I suspect DataSource is indeed the class file.
C. Creating a connection pool is trivial and there are many examples of it - search on this forum or check out your favorite Java/JDBC programming book. Usually, the question "Should I use a connection pool and why?" is a more important question.

Does com.evermind.sql.DriverManagerDataSource provide connection pooling?

Hi,
The class defined in default data-sources.xml file is com.evermind.sql.DriverManagerDataSource. In Oracle9i JDBC Developer's Guide and Reference Release 1 (9.0.1) documentation's chapter 15, Oracle encourages to use this emulated data source for it is fast and efficent.
But I could not find any info about whether com.evermind.sql.DriverManagerDataSource provides connection pooling.
Actually, I want to make sure that if I use default data-sources.xml and ejb-location attribute for lookup method, will I be able to get pooled connection?
Thanks a lot.

Hi,
Thank you for taking your time.
I could manage to get connections from the com.evermind.sql.DriverManagerDataSource using jdbc/OracleDS in JNDI lookup string.
As far as I've understood from the document you pointed out, I could not see "connection pooling" expression directly for emulated class. But there is an explanation that says "Connections retrieved within a single transaction from a data source using the same username and password causes the logical connections to share a single physical connection.". Is this what you've mentioned?
Lastly, how can I make sure that the connections are coming from the pool? Is there a way to see that?
Thanks again.

MTS, OraOLEDB provider, and Connection Pooling

I have read through "Using Microsoft Transaction Server with Oracle8" (http://technet.oracle.com/doc/oracle8i_816/nt.816/a73029/prog.htm#1082299) and the OraOLEDB provider document, and found little coverage in regard to the subject of "Connection Pooling." Could you point me to additional documentation and code samples that would help guide me in designing my application.
I am designing a web based distributed application subsystem with MTS/COM+, OraOLEDB provider (8.1.7.2.0), Oracle Services for MTS (8.1.7.0.0) and Oracle 8i (8.1.6). A major requirement of this subsystem is that it scales well as it is utilized by more and more applications and users. This requirement could be accomplished much easier if the OraOLEDB Provider provides Connection Pooling. Much of the documentation I have seen from Microsoft describes Connection Pooling using ODBC. The documentation from Oracle discusses Connection Pooling with OO4O or OCI. Does the OraOLEDB Provider provide Connection Pooling? If so could you point me to additional documentation and samples?
Thanks,
Bryan Wood

I am facing the same issue. This is strange, no one has responded to this for a year. What does it mean? It sux so bad that no one uses OmniPortlet? It's clear when you execute a sql thru this stupid OmniPortlet it opens a connection and never releases it. I have seen this by turning off everything and keep refreshing the OmniPortlet.
What bothers me more is that there seems to be no freakn documentation on this especially around how to do this from the console and how to use the jndi datasource. There has to be a way. Please help us out on this either from inside or outside oracle.
The world class Oracle support seems to be a joke.

Create A Connection Pool In the ServletContextListener

The Specification says that we should create the connection pool in the ServletContextListener. I have the code for creating a connection pool (see below). How do I create it in the ServletContextListener?
import java.sql.Connection;
import java.sql.SQLException;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;
public class DBConnection
   public static Connection getDBConnection() throws SQLException
      Connection conn = null;
      try
         InitialContext ctx = new InitialContext();
         DataSource ds = ( DataSource ) ctx.lookup( "java:comp/env/jdbc/MySQLDB" );
         try
            conn = ds.getConnection();
         catch( SQLException e )
            System.out.println( "Open connection failure: " + e.getMessage() );
      catch( NamingException nEx )
         nEx.printStackTrace();
      return conn;

I use the connection pool feature provide by the server I use. Is this what I should do? Please confirm.
import java.sql.Connection;
import java.sql.SQLException;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;
import javax.servlet.*;
public class CreateResources implements javax.servlet.ServletContextListener
     public void contextInitialized(ServletContextEvent sce)
          public static Connection getDBConnection() throws SQLException
               Connection conn = null;
               try
                    InitialContext ctx = new InitialContext();
                    DataSource ds = ( DataSource ) ctx.lookup( "java:comp/env/jdbc/MySQLDB" );
                    try
                         conn = ds.getConnection();
                    catch( SQLException e )
                         System.out.println( "Open connection failure: " + e.getMessage() );
              catch( NamingException nEx )
                    nEx.printStackTrace();
              return conn;
     public void contextDestroyed(ServletCotnextEvent sce)
}

Serious connection pool problem on Tomcat

Hi,
We are deploying our JSF creator-made app onto Tomcat 1.5. We set up our JNDI datasource on Tomcat (using the i-net driver ).
Initially the pages load ok but after a short period of time we are getting these errors:
Initialization Failure: javax.faces.FacesException: org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot get a connection, pool exhaustedWe believe that somehow the Creator-generated code is NOT freeing up connections in the connection pool.
We think that when the afterRenderResponse() methods in the beans call rowset.close() this is NOT returning the connections to the pool. Can someone, hopefully a Sun Engineer confirm that the rowset.close() code in afterRenderResponse() returns the connection behind the rowset to the connection pool.
Could this be a driver issue? We are using the i-net driver not the DataDirect one, but this should implement the full API.
This is a very serious problem for us.
regards,
john

do you have any example code you could post? I have a Spring/JSC tutorial on this forum. Just search for Spring and you should find it. It you need something more, I'll try to give you some help...time provided.
am i
right in thinking that you use the forms designer to
lay out your pages and just put your own stuff in the
bean constructor?Close...but not everything goes in the constructor.
>
One thing that may have caused a problem is we have
just noticed that in one of our most commonly hit
pages this line:
dataTable1Model.setDataCacheKey("com.sun.datacache.my_
page.my_rowset");
featured the WRONG "my_page" jsp page but the correct
rowset name "my_rowset". The page DID load correctly
and run correctly, though. Could this cause problems
with connection pooling? Anyone?I wouldn't think so, but it depends on how Creator builds the code.

JDBC connection pool failures when used by JMS stores

 We are using WebLogic 6.1 sp2. We defined a separate connection pool for use by
 a JMS Store.
 <JDBCConnectionPool Name="sybaseJMSPool"
 Targets="cluster00"
 InitialCapacity="2"
 MaxCapacity="10"
 DriverName="com.sybase.jdbc2.jdbc.SybDriver"
 Properties="[email protected]@;[email protected]@;charset=utf8"
 URL="jdbc:sybase:Tds:@jms.db.host@/@jms.db.name@"/>
 (note that the @xxx@ string are replaced by actual values).
 We are using Sybase Jconnect 5.5 to a Sybase ASE 12.5 database.
 We deployed this configuration on a number of environments (testing, staging,
 ..). The actual hardware and network configuration is different for the different
 system, but the WebLogic domain stays the same regarding this issue.
 On the test system we frequently get the following exceptions:
 <Aug 13, 2002 1:56:04 PM CEST> <Alert> <JMS> <www00-test> <node00>
 <ExecuteThread: '6' for queue: 'JMS.TimerClientPool'> <> <> <040048>
 <JMSServer "JMSServer00", store failure while writing message for topic
 OrderChangeTopic, java.io.IOException: JMS JDBC store, connection pool =
 <sybaseJMSPool>, prefix = <JMS00>: write failed
 java.sql.SQLException: JZ006: Caught IOException:
 com.sybase.jdbc2.jdbc.SybConnectionDeadException: JZ0C0: Connection is already
 closed.
 at com.sybase.jdbc2.jdbc.ErrorMessage.raiseErrorCheckDead
 (ErrorMessage.java:715)
 at com.sybase.jdbc2.tds.Tds.handleIOE(Tds.java:3124)
 at com.sybase.jdbc2.tds.Tds.cancel(Tds.java:1412)
 at com.sybase.jdbc2.tds.Tds.cancel(Tds.java:1341)
 at com.sybase.jdbc2.jdbc.SybStatement.doCancel(SybStatement.java:564)
 at com.sybase.jdbc2.jdbc.SybStatement.updateLoop(SybStatement.java:1672)
 at com.sybase.jdbc2.jdbc.SybStatement.executeUpdate
 (SybStatement.java:1625)
 at com.sybase.jdbc2.jdbc.SybPreparedStatement.executeUpdate
 (SybPreparedStatement.java:91)
 at com.p6spy.engine.logging.P6LogPreparedStatement.executeUpdate
 (P6LogPreparedStatement.java:179)
 at weblogic.jdbc.pool.Statement.executeUpdate(Statement.java:293)
 at weblogic.jms.store.JDBCIOStream.write(JDBCIOStream.java:1246)
 at weblogic.jms.store.StoreRequest.doTheIO(StoreRequest.java:250)
 at weblogic.jms.store.JMSStore.execute(JMSStore.java:182)
 at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:139)
 at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120)
 .>
 java.io.IOException: JMS JDBC store, connection pool = <sybaseJMSPool>, prefix
 = <JMS00>: write failed
 java.sql.SQLException: JZ006: Caught IOException:
 com.sybase.jdbc2.jdbc.SybConnectionDeadException: JZ0C0: Connection is already
 closed.
 at com.sybase.jdbc2.jdbc.ErrorMessage.raiseErrorCheckDead
 (ErrorMessage.java:715)
 at com.sybase.jdbc2.tds.Tds.handleIOE(Tds.java:3124)
 at com.sybase.jdbc2.tds.Tds.cancel(Tds.java:1412)
 at com.sybase.jdbc2.tds.Tds.cancel(Tds.java:1341)
 at com.sybase.jdbc2.jdbc.SybStatement.doCancel(SybStatement.java:564)
 at com.sybase.jdbc2.jdbc.SybStatement.updateLoop(SybStatement.java:1672)
 at com.sybase.jdbc2.jdbc.SybStatement.executeUpdate
 (SybStatement.java:1625)
 at com.sybase.jdbc2.jdbc.SybPreparedStatement.executeUpdate
 (SybPreparedStatement.java:91)
 at com.p6spy.engine.logging.P6LogPreparedStatement.executeUpdate
 (P6LogPreparedStatement.java:179)
 at weblogic.jdbc.pool.Statement.executeUpdate(Statement.java:293)
 at weblogic.jms.store.JDBCIOStream.write(JDBCIOStream.java:1246)
 at weblogic.jms.store.StoreRequest.doTheIO(StoreRequest.java:250)
 at weblogic.jms.store.JMSStore.execute(JMSStore.java:182)
 at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:139)
 at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120)
 at weblogic.jms.store.JDBCIOStream.throwIOException
 (JDBCIOStream.java:1213)
 at weblogic.jms.store.JDBCIOStream.write(JDBCIOStream.java:1256)
 at weblogic.jms.store.StoreRequest.doTheIO(StoreRequest.java:250)
 at weblogic.jms.store.JMSStore.execute(JMSStore.java:182)
 at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:139)
 at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120)
 Before that this message appeared:
 <Aug 13, 2002 11:31:16 AM CEST> <Error> <ConnectionManager> <www00-test>
 <node00> <ExecuteThread: '26' for queue: 'default'> <> <> <000000>
 <Closing: 'weblogic.rjvm.t3.T3JVMConnection@795af6' because of: 'Server
 received a message over an uninitialized connection: 'JVMMessage from: 'null'
 to: '-4555218188801970213S:192.168.13.1:[7001,7001,7002,7002,7001,7002,-
 1]:ADIS:node00' cmd: 'CMD_REQUEST', QOS: '101', responseId: '1',
 invokableId: '287', flags: 'JVMIDs Not Sent, TX Context Not Sent', abbrev
 offset: '34'''>
 This problem did not occur on another system which was used during a 2 day stress
 testing session.
 It seems that the problem occurs after a period in which no user request where
 made. The user requests trigger EJB's that start sending JMS messages.
 When the problem occurs, the JMS messaging systems seems to lock up as no messages
 are received anymore by the different listeners (MDBs).
 Undeploying and redeploying the JBDC connection pool solves the problem. This
 solution is unacceptable in case of a production system.
 A similarly defined connection pool, which is used by the EJBs to make database
 connection, does not manifest this problem.
 <JDBCConnectionPool Name="sybasePool"
 Targets="cluster00"
 InitialCapacity="10"
 CapacityIncrement="5"
 MaxCapacity="50"
 PreparedStatementCacheSize="150"
 DriverName="com.sybase.jdbc2.jdbc.SybDriver"
 Properties="[email protected]@;[email protected]@;JCONNECT_VERSION=6;charset=utf8"
 URL="jdbc:sybase:Tds:@db.host@/@db.name@"/>
 The JDBC connection pool is used as follows by the JDBC store
 <JMSJDBCStore ConnectionPool="sybaseJMSPool" Name="JDBCStore00" PrefixName="JMS00"/>
 <JMSServer Name="JMSServer00" Store="JDBCStore00" Targets="node00">
 <JMSTopic JNDIName="ADIS.JMSError" JNDINameReplicated="false" Name="ErrorTopic"/>
 <JMSTopic JNDIName="ADIS.Status"
 Name="StatusTopic" RedeliveryDelayOverride="300000"/>
 <JMSTopic JNDIName="ADIS.OrderChange" JNDINameReplicated="false"
 Name="OrderChangeTopic" RedeliveryLimit="3"/>
 </JMSServer>
 Turning on the "Test Reserved Connection" with a appropriate test table does not
 help.
 Some sources on the internet tell us that JZ0C0 errors in the Jconnect driver
 can be related to network problems. Nevertheless the connection pool should be
 able to cope with this.
 Can you provide any solution for this ? Or give us hints what can cause the problem


Zhenhao Qi wrote:
thanks! Joe.
The SQL statement itself can no longer be simplified, the long excuation time is due to the database size and complicated Select criteria. I can easily reproduce the problem by using this SQL. I tried "BEA's Oracle driver (Type 4): Version 8.1.7,9.0.1,9.2.0". the question can be dissect into 2 pieces:
1) why the jdbc connection (using oracle.jdbc.OracleDriver) won't return anything if the SQL execution time > 5min, that is probably the Oracle's problem
2) why the occupied connection pool won't release even I set "Statementtimeout=600", this is Weblogic's problem.
ZhenhaoHi. Yes, (1) is oracle's problem. (2) may also be. The JDBC spec has very few
allowances for one thread to interrupt a second thread's JDBC call. If we
transmit your timeout request by calling setQueryTimeout() on the oracle
statement, and if you have a weblogic-controlled transaction we call
Statement.cancel() on any ongoing statement, we end up relying on whether
the Oracle driver implements and responds to those calls.
Are you doing weblogic-controlled transactions? Are you/can you
call Statement.setQueryTimeout() on your statements, or are these
generated JDBC queries?
If you can duplicate the problem using the weblogic.jdbc.oracle.OracleDriver
we have some other debug avenues. This would be good even if you really
want to use the thin driver, because we will do the same JDBC calls to
either driver, and the debug would prove (if) we set up a query timeout
and if we call cancel(). If we do, then we can know that it is the Oracle
driver failing in these regards.
Joe

Oracle connection pool problem (dbcp binded with jtom)

Hi,
my webserver is Tomcat5.0.18, I want to offer the connection pool and transaction management
in my currently system
I know in Tomcat5.0 version, we can use the DBCP to offer the database connection pool
service, to apply the transaction management in my system, I adapt the JTOM
now, my problem is
to use DBCP, I setup the datasource factory to be
org.apache.commons.dbcp.BasicDataSourceFactory, the connection pool is ok, but
the transaction management offerred by JTOM will failure
to make the tranaction management of JTOM succeed, I have to setup the datasource factory to be
org.objectweb.jndi.DataSourceFactory, but the connection pool offerred by Tomcat will failure now
it seems that these two datasource factory has conflict
How can I do?, I don't want to use the connection pool offerred in JTOM
Anyone can help me??
Thanks in advance

Hi,
I don't know the solution for JOTM, but you could try this JTA and its connection pools:
http://www.atomikos.com ships a JTA that integrates with Tomcat and also provides JDBC connection pooling. There is a GUI control panel so that you don't have to know the XML details for Tomcat's config files.
Best,
Guy

Doubts concerning External Connection Pool

A few questions:
1. How can I set up an external connection pool with toplink? or in another words, assuming that I have successfully configured a connection pool (and a datasource) on my weblogic app-server, how do I configure Toplink to use the same?
2. I am trying to achieve the above (refer point 1), by defining my custom connector (by extending TOPLink.Public.Sessions.DefaultConnector). The custom connector provides connections using the dataSource.getConnection(). Now, the question is
- Where will the pooling happen in this case? i.e. Will Toplink use its own connection pool (populate its own connection pool with container managed data source), and issue connections (container managed) from there or will it make use of the container managed pooling (and ask for connections from the container managed pool, as and when required)? The subtle difference being, weblogic will not be able to validate a connection before issue in the former case.
3. This question is similar to point 2, but talks in terms of a practical example. Assuming that if I am using the custom connector successfully in my code, then if I pull out the network cord and reconnect again, I expect the container to provide me with a valid connection (as weblogic can be configured to perform a validity check on a connection before issuing). I am getting a 'connection reset by peer' error in my application (indicating that either the container fails to provide a valid connection, or toplink does not use the container managed pool effectively). I guess, Toplink still uses its own pool but this time it is pooling container managed dataSources. Since the connections are issued from Toplink and not container, here is no validation/reconnection happening for the connection, before issue. Please comment if I am thinking in the right direction or not. If not, how you can explain the above failure?
4. My aim is to utilise the container's connection pool, and Toplink's ability to perform the rest of the things (including transactions). Is that possible?

Vikas,
TopLink can easily be configured to use the external connection pool of an server. This can be accomplished with API but more commonly using the sessions.xml configuration file for the SessionManager. In the product we ship examples for WLS that make use of data sources configured in the server. The portion of the sessions.XML file in question is:
 <login>
 <user-name>weblogic</user-name>
 <password>weblogic</password>
 <datasource>java:comp/env/jdbc/ejbJTSDataSource</datasource>
 <non-jts-datasource>java:comp/env/jdbc/ejbNonJTSDataSource</non-jts-datasource>
 <uses-external-transaction-controller>true</uses-external-transaction-controller>
 <uses-external-connection-pool>true</uses-external-connection-pool>
 </login>
 <external-transaction-controller-class>oracle.toplink.jts.wls.WebLogicJTSExternalTransactionController</external-transaction-controller-class>
This sets TopLink up with both data source access to the JTA and non-JTA connection pools. The full example also includes a domain where the data source is configured.
When TopLink is using the connection pool of the server (external connection pooling) it will not pool its own connections. TopLink will request a connection from the pool each time one is required and release it back when done. This leaves the server responsible for the number of connections available and also for supporting database re-connection.
Doug

Oracle Connection Pool failure in COM+

I am having some trouble trying to get a specific database to work with an application that makes use of a COM+ Application. When we point the application at the UAT database everything seems fine, but when we point it to the production database after a few successful calls it ends up failing at the COM+ application recycles. The event viewer provides the following information:
Event Type:     Error
Event Source:     COM+
Event Category:     Unknown
Event ID:     4786
Date:          8/5/2007
Time:          12:54:46 PM
User:          N/A
Computer:     APPL_SERVER
Description:
The system has called a custom component and that component has failed and generated an exception. This indicates a problem with the custom component. Notify the developer of this component that a failure has occurred and provide them with the information below.
Component Prog ID: Oracle Connection Pool - tnsnames_alias
Method Name: IDispenserDriver::CreateResource
Server Application ID: {30A93CB3-25EB-4258-8C88-5AE103B7B86F}
Server Application Instance ID:
{A57C513E-519F-45BD-B46D-DC54B285F534}
Server Application Name: COM+ Application Name
The serious nature of this error has caused the process to terminate.
Exception: C0000005
Address: 0x7C8327F9
Call Stack:
+ 0x7c8327f9
ntdll!RtlFindActivationContextSectionGuid + 0x7d2
ntdll!RtlInitializeSListHead + 0x175
ntdll!RtlFindActivationContextSectionGuid + 0x1b7
msvcrt!malloc + 0x6c
oracommon9!sktsfMalloc + 0x14
orageneric9!kpummapg + 0x58
orageneric9!kghalo + 0xabb
orageneric9!kghalf + 0x102
orageneric9!kopo2cpc + 0x61
orageneric9!kopeini + 0x1d
orageneric9!kopo2cpc + 0xd2
orageneric9!kopopgi + 0x117
OraClient9!koudpnp + 0x712
OraClient9!koudpnp + 0x101
OraClient9!kpuinit0 + 0xb19
OraClient9!kpuinit + 0x38
OraClient9!OCIEnvInit + 0x1c
oramts!kpntsrvr::kpntsrvr(class kpntdbid *) + 0x80
oramts!kpntdbid::allocNewSrvr(struct SIDAND_ATTRIBUTES *) + 0x138
oramts!kpntdbid::GetSrvr(class kpntsvrl * *,unsigned long) + 0x7df
oramts!kpntdisp::getNet8conn(class kpntsvrl * *,unsigned long) + 0x41
oramts!kpntsess::initOCI(void) + 0xec
oramts!kpntsess::sessionBegin(void) + 0x17b
oramts!kpntdisp::CreateResource(unsigned long,unsigned long *,long *) + 0xc4
COMSVCS!DispManGetContext + 0xa3d
COMSVCS!DispManGetContext + 0x1fee
oramts!kpntdisp::allocateConnection(class kpntsess * *,unsigned long,class kpntrtyp *) + 0x3c4
oramts!_kpntsvcgetex + 0x183
oramts!_kpntsvcget + 0x25
oramts!kpntctra::getConnectionAndHandles(class kpntrtyp *,struct OCISvcCtx * *,struct OCITrans * *,struct OCIError * *) + 0x87
oramts!kpntctra::abortBranch(struct xid_t &,class kpntbrnch *,struct BOID *,int,struct BOID *) + 0x15a
oramts!kpntctra::doAbort(struct BOID *,int,struct BOID *) + 0x454
oramts!kpntajob::doJob(void) + 0x27
oramts!kpntjobq::serviceRequest(class kpntjob *) + 0x3e
oramts!workerThread(void *) + 0xd0
msvcrt!_endthreadex + 0xa3
kernel32!GetModuleFileNameA + 0xeb
Not being an expert in Oracle, I have been able to dig up a little bit of information that might be of use ...
a) Our tnsnames.ora indicates that the connections are to be DEDICATED and running Toad bares this out -- dllhost ends up with a single connection.
b) most of the database initial set of parameters seem to be very similar. The only difference I noticed was that the archive log mode and db_cache_advice are ON for production.
c) We have little control over how the connection strings are being created internally in this COM+ application, but however they are created it works for UAT and doesn't for PROD.
d) When we go into our web application and hit a page that makes use of the COM+ component to render, it will work the first time but when I do a simple browser refresh it will usually fail on the 2nd or 3rd time. Almost like it is trying to expand the connection pool size and the oracle server is throwing up.
If I didn't mention earlier the two database instances run on different servers but the application server is exactly the same. We only change the alias we are using for the database (both are defined in tnsnames) and the password used to make its connection.
Does anyone have any clues on this one? I am really spinning my wheels trying to figure out what could cause this type of situation. Anything at all would be very helpful.

It appeared to us that the problem was with the Oracle server and that it might have been failing when we were trying to expand our application connection pool size or basically obtain more connections.
The biggest indicator of this is that we run the same application code against two different databases and one works and one does not work. Having said this, I suppose the problem could be rooted in a data error instead of an oracle server error ...
Is there a specific trace file on the oracle server that would help me point to any error that is truly an oracle server error? Sorry I am very new to Oracle.

Connection pool for ldap

Hi
My application is an interface to ldap directory. I have not used any ldap open source api to retrieve data from ldap. I have written connection pool that will help the application to connect to the ldap. It's working fine, but it's creating threads which are not invited.
ConnectionPool class takes care of the connection storage and creation, while Housekeeping thread relases these connection when idle after a given time.
Can someone please help in finding the problem in the code that creates additional threads.
package com.ba.cdLookup.manager;
import com.ba.cdLookup.exception.CDLookupException;
import com.ba.cdLookup.server.CdLookupProperties;
import java.util.Vector;
import javax.naming.Context;
import javax.naming.NamingException;
public class HouseKeeperThread extends Thread {
 * Apache Logger to log erro/info/debug statements.
 protected static org.apache.commons.logging.Log log = org.apache.axis.components.logger.LogFactory
 .getLog(HouseKeeperThread.class.getName());
 private static HouseKeeperThread houseKeeperThread;
 * Close all connections existing.
 * @param connections
 * void
 private void closeConnections(Vector connections) {
 String methodIdentifier = "closeConnections";
 int numOfConn = connections.size();
 try {
 for (int i = 0; i < numOfConn; i++) {
 Context context = (Context) connections.get(i);
 if (context != null) {
 context.close();
 context = null;
 connections.remove(i);
 numOfConn--;
 log.info(" connection name:" + context
 + " removed. Threadcount =" + (connections.size()));
 } catch (NamingException e) {
 String errMsg = "CDLdapBuilder connect() - failure while releasing connection "
 + " Exception is " + e.toString();
 log.error(errMsg);
 } catch (Exception e) {
 String errMsg = "CDLdapBuilder connect() - failure while releasing connection "
 + " Exception is " + e.toString();
 log.error(errMsg);
 * Thread run method
 public void run() {
 String methodIdentifier = "run";
 try {
 while(true){
 log.debug("house keeping :" + this + " ---sleep");
 //sleep(100000);
 log.debug("house keeping :" + this + " startd after sleep");
 sleep(CdLookupProperties.getHouseKeepConnectionTime());
 ConnectionPool connectionPool = ConnectionPool
 .getConnectionPool();
 Vector connList = connectionPool.getAvailableConnections();
 closeConnections(connList);
 } catch (CDLookupException cde) {
 log.error(methodIdentifier + " " + cde.getStackTrace());
 } catch (InterruptedException ie) {
 log.error(methodIdentifier + " " + ie.getStackTrace());
 * @param connectionPool
 * @return
 * Thread
 public static Thread getInstance() {
 if(houseKeeperThread==null){
 houseKeeperThread = new HouseKeeperThread();
 return houseKeeperThread ;
package com.ba.cdLookup.manager;
import com.ba.cdLookup.exception.CDLookupException;
import com.ba.cdLookup.server.CdLookupProperties;
import com.ba.cdwebservice.schema.cdLookupPacket.LookupFailureReasons;
import java.util.Properties;
import java.util.Vector;
import javax.naming.Context;
import javax.naming.NamingException;
import javax.naming.directory.DirContext;
import javax.naming.directory.InitialDirContext;
* ConnectionPool class manages, allocates LDAP connections. It works as a lazy
* binder and retrieves connections only when required. It doesn't allow
* connection greater then the maximum connection stated.
* To retrieve a connection the singelton method getConnectionPool is to used,
* which retruns thread safe singleton object for the connection.
public class ConnectionPool implements Runnable {
 private int initialConnections = 0;
 private int maxConnections = 0;
 private boolean waitIfBusy = false;
 private Vector availableConnections, busyConnections;
 private boolean connectionPending = false;
 private static int threadCount = 0;
 * classIdentifier
 private final String classIdentifier = "ConnectionPool";
 * Apache Logger to log erro/info/debug statements.
 protected static org.apache.commons.logging.Log log = org.apache.axis.components.logger.LogFactory
 .getLog(CDLdapBuilder.class.getName());
 * To get the attribute a systemaccessfor out of the search result
 private String vendorContextFactoryClass = "com.sun.jndi.ldap.LdapCtxFactory";// "com.ibm.jndi.LDAPCtxFactory";
 * context factory to use
 private String ldapServerUrl = "LDAP://test.ldap.com"; // default ldap
 * server live used by default
 private String searchBase;
 * environment properties.
 private Properties env;
 * DirContext
 private javax.naming.directory.DirContext ctx;
 * default search base to be used in Corporate Directory searches
 private String defaultSearchBase = "dc=Pathway";
 * search criteria
 private String searchAttributes;
 * search filter to retrieve data from CD
 private String searchFilter;
 * CorporateDirectoryLookup Constructor
 * 
 * loads the setup parameters from the properties file and stores them
 * Makes a connection to the directory and sets default search base
 * @throws CDLookupException
 * @throws CDLookupException
 private ConnectionPool() throws CDLookupException {
 this.maxConnections = CdLookupProperties.getMaxConnection();// maxConnections;
 this.initialConnections = CdLookupProperties.getInitialConnection();
 this.waitIfBusy = CdLookupProperties.isWaitIfBusy();
 this.searchBase = CdLookupProperties.getDefaultSearchBase();
 //for local env testing
// this.maxConnections = 5;
// this.initialConnections = 1;
// this.waitIfBusy = true;
 * For keeping no of connections in the connection pool if
 * (initialConnections > maxConnections) { initialConnections =
 * maxConnections; }
 availableConnections = new Vector(maxConnections);
 busyConnections = new Vector(maxConnections);
 for (int i = 0; i < maxConnections; i++) {
 availableConnections.add(makeNewConnection());
 * ConnectionPoolHolder provide Thread safe singleton
 * instance of ConnectionPool class
 private static class ConnectionPoolHolder {
 * connection pool instance
 private static ConnectionPool connectionPool = null;
 * If no ConnectionPool object is present, it creates instance of
 * ConnectionPool class and initiates thread on that.
 * @return ConnectionPool Returns singleton object of ConnectionPool
 * class.
 * @throws CDLookupException
 private static ConnectionPool getInstance() throws CDLookupException {
 if (connectionPool == null) {
 connectionPool = new ConnectionPool();
 new Thread(connectionPool).start();
 // Initiate house keeping thread.
 HouseKeeperThread.getInstance().start();
 return connectionPool;
 * Returns singleton object of ConnectionPool class.
 * @return ConnectionPool
 * @throws CDLookupException
 public static ConnectionPool getConnectionPool() throws CDLookupException {
 return ConnectionPoolHolder.getInstance();
 * getConnection retrieves connections to the corp directory. In case
 * there is no available connections in the pool then it'll try to
 * create one, if the max connection limit for the connection pool
 * reaches then this waits to retrieve one.
 * @return Context
 * @throws CDLookupException
 public synchronized Context getConnection() throws CDLookupException {
 String methodIdentifier = "getConnection";
 if (!availableConnections.isEmpty()) {
 int connectionSize = availableConnections.size() - 1;
 DirContext existingConnection = (DirContext) availableConnections
 .get(connectionSize);
 availableConnections.remove(connectionSize);
 * If connection on available list is closed (e.g., it timed
 * out), then remove it from available list and repeat the
 * process of obtaining a connection. Also wake up threads that
 * were waiting for a connection because maxConnection limit was
 * reached.
 if (existingConnection == null) {
 notifyAll(); // Freed up a spot for anybody waiting
 return (getConnection());
 } else {
 busyConnections.add(existingConnection);
 return (existingConnection);
 } else {
 * Three possible cases: 1) You haven't reached maxConnections
 * limit. So establish one in the background if there isn't
 * already one pending, then wait for the next available
 * connection (whether or not it was the newly established one).
 * 2) You reached maxConnections limit and waitIfBusy flag is
 * false. Throw SQLException in such a case. 3) You reached
 * maxConnections limit and waitIfBusy flag is true. Then do the
 * same thing as in second part of step 1: wait for next
 * available connection.
 if ((totalConnections() < maxConnections) && !connectionPending) {
 makeBackgroundConnection();
 } else if (!waitIfBusy) {
 throw new CDLookupException("Connection limit reached", 0);
 * Wait for either a new connection to be established (if you
 * called makeBackgroundConnection) or for an existing
 * connection to be freed up.
 try {
 wait();
 } catch (InterruptedException ie) {
 String errMsg = "Exception raised =" + ie.getStackTrace();
 log.error(errMsg);
 throw new CDLookupException(classIdentifier, methodIdentifier,
 errMsg, ie);
 // connection freed up, so try again.
 return (getConnection());
 * You can't just make a new connection in the foreground when none are
 * available, since this can take several seconds with a slow network
 * connection. Instead, start a thread that establishes a new
 * connection, then wait. You get woken up either when the new
 * connection is established or if someone finishes with an existing
 * connection.
 private void makeBackgroundConnection() {
 connectionPending = true;
 try {
 Thread connectThread = new Thread(this);
 log.debug("background thread created");
 connectThread.start();
 } catch (OutOfMemoryError oome) {
 log.error("makeBackgroundConnection ="+ oome.getStackTrace());
 * Thread run method
 public void run() {
 String methodIdentifier = "run";
 try {
 Context connection = makeNewConnection();
 synchronized (this) {
 availableConnections.add(connection);
 connectionPending = false;
 notifyAll();
 } catch (Exception e) { // SQLException or OutOfMemory
 // Give up on new connection and wait for existing one
 // to free up.
 String errMsg = "Exception raised =" + e.getStackTrace();
 log.error(errMsg);
 * This explicitly makes a new connection. Called in the foreground when
 * initializing the ConnectionPool, and called in the background when
 * running.
 * @return Context
 * @throws CDLookupException
 private Context makeNewConnection() throws CDLookupException {
 String methodIdentifier = "makeNewConnection";
 Context context = null;
 env = new Properties();
 log.debug("inside " + methodIdentifier);
 try {
 env.put(Context.INITIAL_CONTEXT_FACTORY,
 getVendorContextFactoryClass());
 env.put(Context.PROVIDER_URL, getLdapServerUrl());
 env.put("com.sun.jndi.ldap.connect.pool", "true");
 context = new InitialDirContext(env);
 } catch (NamingException e) {
 String errMsg = "CDLdapBuilder connect() - failure while attempting to contact "
 + ldapServerUrl + " Exception is " + e.toString();
 throw new CDLookupException(classIdentifier, methodIdentifier,
 errMsg, e, LookupFailureReasons.serviceUnavailable);
 } catch (Exception e) {
 String errMsg = "CDLdapBuilder connect() - failure while attempting to contact "
 + ldapServerUrl + " Exception is " + e.toString();
 throw new CDLookupException(classIdentifier, methodIdentifier,
 errMsg, e, LookupFailureReasons.serviceUnavailable);
 log.info("new connection :" + (threadCount++) + " name =" + context);
 log.debug("exit " + methodIdentifier);
 return context;
 * releases connection to the free pool
 * @param context
 public synchronized void free(Context context) {
 busyConnections.remove(context);
 availableConnections.add(context);
 // Wake up threads that are waiting for a connection
 notifyAll();
 * @return int give total no of avail connections.
 public synchronized int totalConnections() {
 return (availableConnections.size() + busyConnections.size());
 * Close all the connections. Use with caution: be sure no connections
 * are in use before calling. Note that you are not required to
 * call this when done with a ConnectionPool, since connections are
 * guaranteed to be closed when garbage collected. But this method gives
 * more control regarding when the connections are closed.
 public synchronized void closeAllConnections() {
 closeConnections(availableConnections);
 availableConnections = new Vector();
 closeConnections(busyConnections);
 busyConnections = new Vector();
 * Close all connections existing.
 * @param connections
 * void
 private void closeConnections(Vector connections) {
 String methodIdentifier = "closeConnections";
 try {
 for (int i = 0; i < connections.size(); i++) {
 Context context = (Context) connections.get(i);
 if (context != null) {
 log.info(" connection name:" + context
 + " removed. Threadcount =" + (threadCount++));
 context.close();
 context = null;
 } catch (NamingException e) {
 String errMsg = "CDLdapBuilder connect() - failure while attempting to contact "
 + ldapServerUrl + " Exception is " + e.toString();
 log.error(errMsg);
 public synchronized String toString() {
 String info = "ConnectionPool(" + getLdapServerUrl() + ","
 + getVendorContextFactoryClass() + ")" + ", available="
 + availableConnections.size() + ", busy="
 + busyConnections.size() + ", max=" + maxConnections;
 return (info);
 * @return the defaultSearchBase
 public final String getDefaultSearchBase() {
 return defaultSearchBase;
 * @param defaultSearchBase
 * the defaultSearchBase to set
 public final void setDefaultSearchBase(String defaultSearchBase) {
 this.defaultSearchBase = defaultSearchBase;
 * @return the ldapServerUrl
 public final String getLdapServerUrl() {
 return ldapServerUrl;
 * @param ldapServerUrl
 * the ldapServerUrl to set
 public final void setLdapServerUrl(String ldapServerUrl) {
 this.ldapServerUrl = ldapServerUrl;
 * @return the vendorContextFactoryClass
 public final String getVendorContextFactoryClass() {
 return vendorContextFactoryClass;
 * @param vendorContextFactoryClass
 * the vendorContextFactoryClass to set
 public final void setVendorContextFactoryClass(
 String vendorContextFactoryClass) {
 this.vendorContextFactoryClass = vendorContextFactoryClass;
 * @return the availableConnections
 public final Vector getAvailableConnections() {
 return availableConnections;
}

Hi,
As the connection pool implmentation has the bug of not extending more than the min size, workaround I use is MIN_CONN=100 and MAX_CONN=101,and just waiting for the bug to get fixed. (using Netscape SDK for java4.0)

Connection Pool establishment problem

Hi Experts,
we have one application with JCo mechanism. For this application,
we are using one properties file, which holds ABAP connection information. From this connection information(sapconn.props), we created connection pool and fetching data from the back end. Now my requirement is, instead of this properties file, we want to use one SLD, from this i would like to fetch connection information and establish a connection pool. How can we implement this one...?
Is there any API to read the ABAP connection informaation from visual admin (JCo RFC provider) ?
Thanks
maha

Your question has been answered in this [thread|connection establishment doubt;.
Please read the [rules|https://wiki.sdn.sap.com/wiki/display/HOME/RulesofEngagement], in particular - do not cross post.
-- Vladimir

Connection pool and Connection factory difference?

Hi,
Can someone clarify the difference between connection pool and connection factory.
I know connection pool is some thing like a pool of database connection manitained at one place so that an application or client can use it when it requires.
Then wat exactly is connection factory..say in 10g we always put a connection factory name in all adapters and acces the data sources like DB ,FTP,AQ ..etc
can someone clarify??
regards,

To conserve system resources and to improve the performance of transactional applications, WebLogic allows you to define a pool of client connections (generally database but may be a FTP,FILE etc. as well)
A Connection Factory object encapsulates a set of connection configuration parameters that has been defined by an administrator. A client uses it to create a connection with a service provider (generally JMS).
Regards,
Anuj

Difference between connection pooling and simple connection

Anybody please tell me what is the Difference between connection pooling and simple connection and also where we define connection pooling and how.
Thanks
Please reply soon
amitindia

Creating and closing connection to the database is a relatively slow process. Equally connections use database resources so you can't just open as many as you want.
A connection pool maintains a number of open connections throughout the lifetime of the application. Instead of opening and closing the connections your application just "borrows" them from the pool when they're needed.
If the pool runs out of connections it will usually create new ones as needed until you reach some predefined upper limit.
A good connection pool will also manage connections which have failed for any reason, and report code which fails to return connections to the pool (ie connection leaks).
The number of connections created at startup is referred to as the "low water mark" and the maximum number that the pool will allow to be opened at any given time is the "high water mark". If no connections are available client code will generally block until one is released.
If by "defined" you mean where can you get a working implementation then your database or application server vendor is likely to provide one. Also the Apache Jakarta Commons includes [url http://jakarta.apache.org/commons/dbcp/]an implementation which you can use with any JDBC driver.
Dave.

Connection Pooling in a JAAS Provider

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