How to Capture deadlock in SQL server | Trace deadlock | SQL interview Q&A | Ms SQL

This video focus on how to capture a deadlock in SQL server. If you are a beginner then this video is for you. Please refer below video reference links that are discussed in this video.

What is a deadlock and how it occurs
https://youtu.be/f66ehM4Gn84

How SQL server choses a deadlock victim
https://youtu.be/junA5eB8Ifs



T-SQL script to find How many deadlock occured since server startup
SELECT 'Deadlocks Occurrence',
CONVERT(BIGINT,((1.0 * v.cntr_value /
NULLIF(datediff(DD,w.create_date,CURRENT_TIMESTAMP),0)))) as
AvgPerDay,
CAST(v.cntr_value AS NVARCHAR(100)) + ' deadlocks recorded since startup.' AS Details,
w.create_date as StartupDateAndTime
FROM sys.dm_os_performance_counters v
INNER JOIN sys.databases w ON w.name = 'tempdb'
WHERE RTRIM(v.counter_name) = 'Number of Deadlocks/sec'
AND RTRIM(v.instance_name) = '_Total'

Turn on Trace flags
DBCC TRACEON (1204, -1)
DBCC TRACEON (1222, -1)


Analyzing Deadlocks with SQL Server Profiler
https://learn.microsoft.com/en-us/previous-versions/sql/sql-server-2008-r2/ms188246(v=sql.105)

Microsoft technet on System health extended event
https://social.technet.microsoft.com/wiki/contents/articles/31280.finding-and-extracting-deadlock-information-using-extended-events.aspx

Analyze & prevent deadlocks
a. https://learn.microsoft.com/en-us/sql/relational-databases/sql-server-deadlocks-guide?view=sql-server-ver16
b. https://learn.microsoft.com/en-us/azure/azure-sql/database/analyze-prevent-deadlocks?view=azuresql&tabs=ring-buffer#prevent-a-deadlock-from-reoccurring