Blocking is one of those issues that can touch many aspects of SQL Server. Although investigating blocking benefits from an understanding of how SQL Server works, it is also a good way to learn even more about the server. Of course, the immediate need to resolve blocking is often more important than learning more about the server. The intent of this chapter was to provide you with the tools and knowledge you need to face those situations when the phone is ringing off the hook on Monday morning because system performance has dropped through the floor due to heavy blocking.
And, remember that the locks in blocking you see might not have been acquired in the blocker’s current statement. Look at the previous statements in the transaction; it might be immediately obvious why the locks are being held.