where is _isIBMi declaration?..
how is _isIBMi used to configure ConnectionPool?
Martin
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> Date: Sun, 21 Jun 2009 13:25:25 -0600
> From: p...@valadd.com
> To: users@tomcat.apache.org
> Subject: Re: Pointers on diagnosing session and thread hangs
>
> "For curiosity's sake, why did you roll your own DB pooling, rather than
> letting Tomcat manage it?"
>
> That is a good question and one I am not sure I can easily answer since
> the base code I am working with was originally written by someone else 6
> years ago. I am not sure if DB pooling was implemented back then, but we
> have a particular platform where we need to call some system routines
> before making the connection and so this driver is just small piece of
> code handles that system call and all the DB connecting and pooling. I
> am not sure why the pooling was implemented in this code since my
> understanding is that the JDBC driver usually handles this.
>
> We then added some additional support for other DB's into this code so
> that the web application can stay completely agnostic to the database it
> is connecting to. We specify different JDBC connection information in
> the configuration file that the DB Manager code references. So I guess
> the bottom line is that this code exists to keep the webapp independent
> of the database but why pooling was implemented in the driver is
> something that we are now looking into since it appears to be the point
> of pain.
>
> FWIW the code from the relevant method is:
>
> public DataSource setupDataSource(String userName, String password,
> String connectURI, String roleID, boolean doAdd) {
> //
> // First, we'll need a ObjectPool that serves as the
> // actual pool of connections.
> //
> // We'll use a GenericObjectPool instance, although
> // any ObjectPool implementation will suffice.
> //
> if(_debug)
> System.out.println("Setting up datasource with Role:
> "+roleID); //Specific to our implementation
>
> ObjectPool connectionPool = new GenericObjectPool(null, maxActive,
> whenExhaustedAction, maxWait, maxIdle, minIdle,
> testOnBorrow, testOnReturn, timeBetweenEvictionRunsMillis,
> numTestsPerEvictionRun, minEvictableIdleTimeMillis,
> testWhileIdle);
> //
> // Next, we'll create a ConnectionFactory that the
> // pool will use to create Connections.
> // We'll use the DriverManagerConnectionFactory,
> // using the connect string passed in the command line
> // arguments.
> //
> ConnectionFactory connectionFactory = new
> DriverManagerConnectionFactory(
> connectURI, userName, password);
> //
> // Now we'll create the PoolableConnectionFactory, which wraps
> // the "real" Connections created by the ConnectionFactory with
> // the classes that implement the pooling functionality.
> //
> PoolableConnectionFactory pool = null;
>
> // Code to handle member overrides specific to IBM i
>
> if(_debug)
> System.out.println("Creating connection pool using
> PoolableConnectionFactory");
> pool = new PoolableConnectionFactory(
> connectionFactory, connectionPool, null, null,
> false, true) {
> /*
> * (non-Javadoc)
> *
> * @see
> org.apache.commons.dbcp.PoolableConnectionFactory#makeObject()
> */
>
> public synchronized Object makeObject() throws Exception {
> // This line of code is BLOCKED randomly
> Connection conn = (Connection) super.makeObject();
> // Code to handle member overrides specific to IBM i
> if(_isIBMi.equals("Y"))
> if(_debug)
> System.out.println("Preparing member
> connection");
> //Calls the override routines on the IBM i system
> databaseManager.prepareMemberConnection(conn);
>
> return conn;
> }
> };
>
> }
> else
> {
> if(_debug)
> System.out.println("Creating connection pool using
> PoolableConnectionFactory");
> pool = new PoolableConnectionFactory(
> connectionFactory, connectionPool, null, null, false, true);
> }
> //
> // Finally, we create the PoolingDriver itself,
> // passing in the object pool we created.
> //
> if(_debug)
> System.out.println("Creating PoolingDataSource");
> PoolingDataSource dataSource = new
> PoolingDataSource(connectionPool);
>
> pool.setDefaultAutoCommit(defaultAutoCommit);
> pool.setDefaultCatalog(defaultCatalog);
> pool.setDefaultReadOnly(defaultReadOnly);
> //pool.setDefaultTransactionIsolation(defaultTransactionIsolation);
> if (validationQuery != null)
> pool.setValidationQuery(validationQuery);
>
> dataSource
>
> .setAccessToUnderlyingConnectionAllowed(accessToUnderlyingConnectionAllowed);
>
> try {
> for (int i = 0; i < initialSize; i++) {
> if(_debug)
> System.out.println("Adding object to pool up to
> initial size");
> connectionPool.addObject();
> }
> }
> catch (Exception e) {
> e.printStackTrace();
> }
> if (doAdd == true)
> {
> if(_debug)
> System.out.println("Adding object to pool");
> _pools.put(roleID, connectionPool);
> _dataSources.put(roleID, dataSource);
> }
> return dataSource;
> }
>
> I will need to find out why the code is structured this way,
> particularly the makeObject calls. And, again, the thread dump has been
> very helpful in sorting this all out.
>
> Pete
>
>
> Caldarale, Charles R wrote:
> >> From: Pete Helgren [mailto:p...@valadd.com]
> >> Subject: Re: Pointers on diagnosing session and thread hangs
> >>
> >> I am looking at the DB Manager code I wrote to see if I am doing
> >> something wrong in implementing the pooling.
> >>
> >
> > For curiosity's sake, why did you roll your own DB pooling, rather than
> > letting Tomcat manage it?
> >
> > - Chuck
> >
> >
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