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/src/org/eclipse/birt/data/engine/impl/PreparedJointDataSourceQuery.java
Iterator bindingIt = parameterBindings.iterator( );
			while ( bindingIt.hasNext( ) )
			{
				InputParameterBinding iipb = (InputParameterBinding) bindingIt.next( );
				if(JointDataSetParameterUtil.isDatasetParameter( dataSetDesignName, isLeftDataSet, iipb.getName( ) ))
				{
					queryDefinition.addInputParamBinding( new InputParameterBinding( 
							JointDataSetParameterUtil.extractParameterName( iipb.getName( )  ),
							iipb.getExpr( ) ) );
				}
			}
		}
	}
	/**
	 * Add a sort expression to preparedQuery.
	 * 
	 * @param joinConditions
	 * @param isLeftDataSet
	 * @param preparedQuery
	 */
	private void addSortToPreparedQuery( IJoinCondition condition,
			boolean isLeftDataSet, IPreparedQuery preparedQuery )
	{
		IScriptExpression sortExpression;
		if ( isLeftDataSet )
		{
			sortExpression = condition.getLeftExpression( );
		}
		else
		{