Daily Archives: Nov 4, 2014


Locking, Blocking and Deadlocking in sql server 1

Lock vs Block vs Deadlock

Have you ever asked to differentiate lock, block and deadlock in sql server during your interview session? In this article we are going to differentiate these frequently confused terms – Lock, Block and Deadlock. So lets have a look on “Lock vs Block vs Deadlock”

These terms sound the same but are different in their meanings. Have a look on below definition to understand it.

Lock

When any session needs access to a piece of data from Database, a lock of some type is placed on that data to maintain the isolation property of database. Locking is different from blocking.

Block

When a session needs to wait for a resource being locked by another session, this process is called as blocking. e.g. If session “A” is waiting for a resource “R” being used by session “B”, you can say that session “B” is blocking session … More