Bug 136141 Prepared statements not properly cleaned up.
After designing a JDBC query in a report design, I opened the DataSetEditor and choose "Preview Results". There are a number of warnings that came up in the Console indicating there are prepared statements not properly managed or cleaned up. Apr 11, 2006 8:23:04 AM org.eclipse.birt.data.engine.executor.DataSource close WARNING: 1 statements still active. Apr 11, 2006 8:23:05 AM org.eclipse.birt.data.engine.executor.DataSource closeStatement WARNING: statement not found Tracing down the problem a little further, the root cause of the problem is because the DataSourceQuery (in data.engine.executor) is trying to close a dangling reference of a PreparedStatement. The PreparedStatement has been previously dropped from the statementMap of the DataSource when the DataSource.close() was called. But DataSourceQuery is still holding on to a reference of it. The sequence is as follows: 1) DataSourceQuery prepares a statement. This in turn makes DataSource prepare a statement, and creates a PreparedStatement object, adds it to the statementMap. 2) During DataEngineImpl.defineDataSource(), the existing DataSource is closed, replaced by the supplied DataSourceDesign. The DataSource still have statements in its map. And a warning is logged indicating this is a resource leak. It then cleans the statementMap and closes all its open connections. 3) When DataSourceQuery tries to close the dangling statement, it cannot find it. It logs a message "Statement not found". Then, it still proceeds to close it.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/executor/DataSource.java
conn.maxStatements = max;
    	this.odaConnections.add( conn );
    	return conn;
    }
    
    /** 
     * Find a connection available for new statements in the pool, or create
     * a new one if none available 
     */
    private CacheConnection getAvailableConnection() throws DataException
	{
    	Iterator it = odaConnections.iterator();
    	while ( it.hasNext() )
    	{
    		CacheConnection c = (CacheConnection) (it.next());
    		if ( c.currentStatements < c.maxStatements )
    			return c;
    	}
    	
    	
    	return newConnection();
	}
    /*
     * @see org.eclipse.birt.data.engine.odi.IDataSource#newQuery(java.lang.String, java.lang.String)
     */
    public IDataSourceQuery newQuery(String queryType, String queryText) throws DataException
    {
    	
        return new DataSourceQuery(this, queryType, queryText);
    }