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
/*
     * @see org.eclipse.birt.data.engine.odi.IDataSource#newCandidateQuery()
     */
    public ICandidateQuery newCandidateQuery()
    {
       	
		return new CandidateQuery( );
    }
    
    /**
     * Prepares an ODA Statement. May use an existing Connection from the pool
     * which has free active statements, or a new connection if all connections
     * in pool have readed their maximum active statements.
     * Returned PreparedStatement must be closed by calling closeStatement.
     */
    synchronized PreparedStatement prepareStatement ( String queryText, String dataSetType )
    	throws DataException
    {
        assert isOpen();
        CacheConnection conn = getAvailableConnection();
        assert conn.currentStatements < conn.maxStatements;
        ++ conn.currentStatements;
        PreparedStatement stmt = conn.odaConn.prepareStatement( queryText, dataSetType );
        
        
        
        this.statementMap.put( stmt, conn );
        return stmt;
    }