Monitoring Blocking in SQL Server

Hello to everyone,

In this article, I will try to give information about monitoring blocking in SQL Server.

You may want to watch blocking and waits in SQL Server in some cases.

You can easily do this using the code below.

SET NOCOUNT ON;
GO
SELECT spid,
       blocked,
       REPLACE(REPLACE(T.text, CHAR(10), ' '), CHAR(13), ' ') AS BATCH
INTO #T
FROM sys.sysprocesses R
    CROSS APPLY sys.dm_exec_sql_text(R.sql_handle) T;
GO
WITH BLOCKERS (SPID, BLOCKED, LEVEL, BATCH)
AS (SELECT spid,
           blocked,
           CAST(REPLICATE('0', 4 - LEN(CAST(spid AS VARCHAR))) + CAST(spid AS VARCHAR) AS VARCHAR(1000)) AS LEVEL,
           BATCH
    FROM #T R
    WHERE (
              blocked = 0
              OR blocked = spid
          )
          AND EXISTS
    (
        SELECT * FROM #T R2 WHERE R2.blocked = R.spid AND R2.blocked <> R2.spid
    )
    UNION ALL
    SELECT R.spid,
           R.blocked,
           CAST(BLOCKERS.LEVEL + RIGHT(CAST((1000 + R.spid) AS VARCHAR(100)), 4) AS VARCHAR(1000)) AS LEVEL,
           R.BATCH
    FROM #T AS R
        INNER JOIN BLOCKERS
            ON R.blocked = BLOCKERS.SPID
    WHERE R.blocked > 0
          AND R.blocked <> R.spid)
SELECT N'    ' + REPLICATE(N'|         ', LEN(LEVEL) / 4 - 1) + CASE
                                                                    WHEN (LEN(LEVEL) / 4 - 1) = 0 THEN
                                                                        'HEAD -  '
                                                                    ELSE
                                                                        '|------  '
                                                                END + CAST(SPID AS NVARCHAR(10)) + N' ' + BATCH AS BLOCKING_TREE
FROM BLOCKERS
ORDER BY LEVEL ASC;
GO
DROP TABLE #T;
GO

Good luck to everyone in business and life.