Bug 180189 Support in memory data set cache.
Currently, Design-Time Data Cache is stored on disks. By performance tests using ramdisk, we found that caching in physical memory can improve the performance of RunAndRender by 30%.
data/org.eclipse.birt.data.tests/test/org/eclipse/birt/data/engine/binding/DataSetCacheTest.java
bindingNameRow[0] = "ROW_NUM";
		bindingNameRow[1] = "ROW_SQUARE";
		bindingNameRow[2] = "ROW_STR";
		IBaseExpression[] expressionArray = new IBaseExpression[3];
		ScriptExpression expr = new ScriptExpression( "dataSetRow.NUM" );
		expressionArray[0] = expr;
		expr = new ScriptExpression( "dataSetRow.SQUARE" );
		expressionArray[1] = expr;
		expr = new ScriptExpression( "dataSetRow.STR" );
		expressionArray[2] = expr;
		for ( int i = 0; i < bindingNameRow.length; i++ )
			queryDefinition.addResultSetExpression( bindingNameRow[i],
					expressionArray[i] );
		rowBeArray = expressionArray;
		myDataEngine2.defineDataSource( odaDataSource );
		myDataEngine2.defineDataSet( odaDataSet );
		IQueryResults qr = myDataEngine2.prepare( queryDefinition )
				.execute( null );
		return qr.getResultIterator( );
	}
	/**
	 * @return
	 * @throws BirtException
	 */
	private DataEngineImpl newDataEngine( ) throws BirtException
	{
		DataEngineImpl myDataEngine = (DataEngineImpl) DataEngine.newDataEngine( DataEngineContext.newInstance( DataEngineContext.DIRECT_PRESENTATION,
				null,
				null,
				null ) );