Queue Processing Using Updlock, Readpast Locking Hints

This article instructed me on how to process rows from a table used as a data queue for multiple processes.

http://www.mssqltips.com/tip.asp?tip=1257

I tested this against the AdventureWorks DB (SQL 2005) and multiple SQL connections inside of Sql Mgmt. Studio).

Connection1:


BEGIN TRANSACTION


SELECT TOP 1 * FROM Production.WorkOrder WITH (updlock, readpast) --skips over locked rows
--COMMIT TRANSACTION

Connection2:


BEGIN TRANSACTION


SELECT TOP 1 * FROM Production.WorkOrder WITH (updlock, readpast) --skips over locked rows

COMMIT TRANSACTION



This works like I want where connection 2 skips over the locked row from connection 1 and gets the next available record from the table / queue. However, when I add ORDER BY tsql to each sql statement, connection 2 is now blocked waiting for Connection 1 to commit. (This is not what I want)

Connection1:


BEGIN TRANSACTION


SELECT TOP 1 * FROM Production.WorkOrder WITH (updlock, readpast) order by DueDate

--COMMIT TRANSACTION

Connection2:


BEGIN TRANSACTION


SELECT TOP 1 * FROM Production.WorkOrder WITH (updlock, readpast) order by DueDate --is blocked until connection 1 commits transaction

COMMIT TRANSACTION




How do I prevent blocking when using these locking hints with ORDER BY?


thanks