How to deliberately cause a deadlock?

Question

So I\'m trying to track down what looks like a deadlock problem here. I\'ve enabled deadlock logging using DBCC TRACEON(1222,-1) and DBCC TRACEON(1204 ,-1). I\'d like to t

Answer 1

Here's some T-SQL to deliberately cause a deadlock.

Object creation:

CREATE TABLE dbo.DeadLockTest (col1 INT)
INSERT dbo.DeadLockTest SELECT 1

CREATE TABLE dbo.DeadLockTest2 (col1 INT)
INSERT dbo.DeadLockTest2 SELECT 1

Open up a new query window and paste this code and execute it:

BEGIN TRAN
UPDATE dbo.DeadLockTest SET col1 = 1

Open up another new query window and paste and execute this code:

BEGIN TRAN
UPDATE dbo.DeadLockTest2 SET col1 = 1
UPDATE dbo.DeadLockTest SET col1 = 1

Go back to your first query window (with the first BEGIN TRAN statement) and execute this code:

UPDATE dbo.DeadLockTest2 SET col1 = 1

Voila! That's a deadlock.

Answer 2

This should work:

• Insert two records, A and B.
  
• Open two transactions.
  
• Update record A in the first transaction and B in the second transaction.
  
• When you know for sure those updates are done:
  
  • Update record B in the first transaction and A in the second transaction.