How to Find Blocking and Deadlock in SQL Server - SQL Server DBA Tutorial

1. What is deadlock in SQL Server?
2. What is Blocking in SQL Server?
3. What is difference between deadlock and blocking in SQL Server?
4. How to create deliberate deadlock for learning purposes?
5. What are the deadlock traces in SQL Server?
6. How to turn on deadlock traces on and off in SQL Server?
7. How and where to check deadlock information in SQL Server?

--Scripts: How to check blocking in SQL Server 
Exec sp_who;
GO
--How to turn onandoff traces andcheck Traces onSQL Server
DBCC TRACESTATUS();
--How tocheckIf Deadlock traces are enabled or disabled
DBCC TRACESTATUS(1204,1222, -1)
--How to Turn Deadlock Traces onSQL Server
DBCC TRACEON(1204,1222, -1)
--How to Turn deadlock Traces Off
DBCC TRACEOFF(1204,1222, -1)


--How to create deliberate deadlock

-- Tran1

CREATETABLE DemoDeadLock1 (SessionNumber INT)
INSERT DemoDeadLock1 SELECT 1

CREATETABLE DemoDeadLock2 (SessionNumber INT)
INSERT DemoDeadLock2 SELECT 1

--Tran2 in new session
BEGINTRAN
UPDATE  DemoDeadLock1 SET  SessionNumber= 1

--Tran3
BEGINTRAN
UPDATE  DemoDeadLock2 SET SessionNumber = 1
UPDATE  DemoDeadLock1 SET SessionNumber = 1

--Let's update Demodeadlock2 table in our Tran2 session
UPDATE DemoDeadLock2 SET SessionNumber = 1