Bug 124444 Preview attached file in pdf will display nothing.
Description: Preview attached file in pdf will display nothing. Steps to reproduce: 1. Preview attached design file in pdf Expected result: Report content shows Actual result: Wait for 10 minutes but nothing showed at all
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/executor/QueryItemExecutor.java
* close dataset if the dataset is not null:
	 * <p>
	 * <ul>
	 * <li>close the dataset.
	 * <li>exit current script scope.
	 * </ul>
	 * 
	 * @param ds
	 *            the dataset object, null is valid
	 */
	protected void closeResultSet( )
	{
		if ( rset != null )
		{
			rset.close( );
		}
	}
	/**
	 * register dataset of this item.
	 * <p>
	 * if dataset design of this item is not null, create a new
	 * <code>DataSet</code> object by the dataset design. open the dataset,
	 * move cursor to the first record , register the first row to script
	 * context, and return this <code>DataSet</code> object if dataset design
	 * is null, or open error, or empty resultset, return null.
	 * 
	 * @param item
	 *            the report item design
	 * @return the DataSet object if not null, else return null
	 */