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
while ( ri.next( ) )
		{
			for ( int i = 0; i < bindingNameRow.length; i++ )
				expectedValue.add( ri.getValue( bindingNameRow[i] ) );
		}
		ri.close( );
		myDataEngine2.shutdown( );
	}
	/**
	 * @throws BirtException
	 */
	private void useCache2( ) throws BirtException
	{
		DataEngineContext context = DataEngineContext.newInstance( DataEngineContext.DIRECT_PRESENTATION,
				null,
				null,
				null );
		context.setCacheOption( DataEngineContext.CACHE_USE_ALWAYS, 4 );
		DataEngine myDataEngine2 = DataEngine.newDataEngine( context );
		IResultIterator ri = getResultIterator2( myDataEngine2 );
		checkResult( ri );
		ri.close( );
		myDataEngine2.shutdown( );
	}
	/**
	 * 
	 * @param myDataEngine
	 * @return
	 * @throws BirtException
	 */