[sql] How to check which locks are held on a table

How can we check which database locks are applied on which rows against a query batch?

Any tool that highlights table row level locking in real time?

DB: SQL Server 2005

You can find details via the below script.

-- List all Locks of the Current Database 
SELECT TL.resource_type AS ResType 
      ,TL.resource_description AS ResDescr 
      ,TL.request_mode AS ReqMode 
      ,TL.request_type AS ReqType 
      ,TL.request_status AS ReqStatus 
      ,TL.request_owner_type AS ReqOwnerType 
      ,TAT.[name] AS TransName 
      ,TAT.transaction_begin_time AS TransBegin 
      ,DATEDIFF(ss, TAT.transaction_begin_time, GETDATE()) AS TransDura 
      ,ES.session_id AS S_Id 
      ,ES.login_name AS LoginName 
      ,COALESCE(OBJ.name, PAROBJ.name) AS ObjectName 
      ,PARIDX.name AS IndexName 
      ,ES.host_name AS HostName 
      ,ES.program_name AS ProgramName 
FROM sys.dm_tran_locks AS TL 
     INNER JOIN sys.dm_exec_sessions AS ES 
         ON TL.request_session_id = ES.session_id 
     LEFT JOIN sys.dm_tran_active_transactions AS TAT 
         ON TL.request_owner_id = TAT.transaction_id 
            AND TL.request_owner_type = 'TRANSACTION' 
     LEFT JOIN sys.objects AS OBJ 
         ON TL.resource_associated_entity_id = OBJ.object_id 
            AND TL.resource_type = 'OBJECT' 
     LEFT JOIN sys.partitions AS PAR 
         ON TL.resource_associated_entity_id = PAR.hobt_id 
            AND TL.resource_type IN ('PAGE', 'KEY', 'RID', 'HOBT') 
     LEFT JOIN sys.objects AS PAROBJ 
         ON PAR.object_id = PAROBJ.object_id 
     LEFT JOIN sys.indexes AS PARIDX 
         ON PAR.object_id = PARIDX.object_id 
            AND PAR.index_id = PARIDX.index_id 
WHERE TL.resource_database_id  = DB_ID() 
      AND ES.session_id <> @@Spid -- Exclude "my" session 
      -- optional filter  
      AND TL.request_mode <> 'S' -- Exclude simple shared locks 
ORDER BY TL.resource_type 
        ,TL.request_mode 
        ,TL.request_type 
        ,TL.request_status 
        ,ObjectName 
        ,ES.login_name;



--TSQL commands
SELECT 
       db_name(rsc_dbid) AS 'DATABASE_NAME',
       case rsc_type when 1 then 'null'
                             when 2 then 'DATABASE' 
                             WHEN 3 THEN 'FILE'
                             WHEN 4 THEN 'INDEX'
                             WHEN 5 THEN 'TABLE'
                             WHEN 6 THEN 'PAGE'
                             WHEN 7 THEN 'KEY'
                             WHEN 8 THEN 'EXTEND'
                             WHEN 9 THEN 'RID ( ROW ID)'
                             WHEN 10 THEN 'APPLICATION' end  AS 'REQUEST_TYPE',

       CASE req_ownertype WHEN 1 THEN 'TRANSACTION'
                                     WHEN 2 THEN 'CURSOR'
                                     WHEN 3 THEN 'SESSION'
                                     WHEN 4 THEN 'ExSESSION' END AS 'REQUEST_OWNERTYPE',

       OBJECT_NAME(rsc_objid ,rsc_dbid) AS 'OBJECT_NAME', 
       PROCESS.HOSTNAME , 
       PROCESS.program_name , 
       PROCESS.nt_domain , 
       PROCESS.nt_username , 
       PROCESS.program_name ,
       SQLTEXT.text 
FROM sys.syslockinfo LOCK JOIN 
     sys.sysprocesses PROCESS
  ON LOCK.req_spid = PROCESS.spid
CROSS APPLY sys.dm_exec_sql_text(PROCESS.SQL_HANDLE) SQLTEXT
where 1=1
and db_name(rsc_dbid) = db_name()



--Lock on a specific object
SELECT * 
FROM sys.dm_tran_locks
WHERE resource_database_id = DB_ID()
AND resource_associated_entity_id = object_id('Specific Table');

I use a Dynamic Management View (DMV) to capture locks as well as the object_id or partition_id of the item that is locked.

(MUST switch to the Database you want to observe to get object_id)

SELECT 
     TL.resource_type,
     TL.resource_database_id,
     TL.resource_associated_entity_id,
     TL.request_mode,
     TL.request_session_id,
     WT.blocking_session_id,
     O.name AS [object name],
     O.type_desc AS [object descr],
     P.partition_id AS [partition id],
     P.rows AS [partition/page rows],
     AU.type_desc AS [index descr],
     AU.container_id AS [index/page container_id]
FROM sys.dm_tran_locks AS TL
INNER JOIN sys.dm_os_waiting_tasks AS WT 
 ON TL.lock_owner_address = WT.resource_address
LEFT OUTER JOIN sys.objects AS O 
 ON O.object_id = TL.resource_associated_entity_id
LEFT OUTER JOIN sys.partitions AS P 
 ON P.hobt_id = TL.resource_associated_entity_id
LEFT OUTER JOIN sys.allocation_units AS AU 
 ON AU.allocation_unit_id = TL.resource_associated_entity_id;

You can find current locks on your table by following query.

USE yourdatabase;
GO

SELECT * FROM sys.dm_tran_locks
  WHERE resource_database_id = DB_ID()
  AND resource_associated_entity_id = OBJECT_ID(N'dbo.yourtablename');

See sys.dm_tran_locks

If multiple instances of the same request_owner_type exist, the request_owner_id column is used to distinguish each instance. For distributed transactions, the request_owner_type and the request_owner_guid columns will show the different entity information.

For example, Session S1 owns a shared lock on Table1; and transaction T1, which is running under session S1, also owns a shared lock on Table1. In this case, the resource_description column that is returned by sys.dm_tran_locks will show two instances of the same resource. The request_owner_type column will show one instance as a session and the other as a transaction. Also, the resource_owner_id column will have different values.

You can find blocking sql and wait sql by running this:

SELECT
    t1.resource_type ,
    DB_NAME( resource_database_id) AS dat_name ,
    t1.resource_associated_entity_id,
    t1.request_mode,
    t1.request_session_id,
    t2.wait_duration_ms,
    ( SELECT TEXT FROM sys.dm_exec_requests r CROSS apply sys.dm_exec_sql_text ( r.sql_handle ) WHERE r.session_id = t1.request_session_id ) AS wait_sql,
    t2.blocking_session_id,
    ( SELECT TEXT FROM sys.sysprocesses p CROSS apply sys.dm_exec_sql_text ( p.sql_handle ) WHERE p.spid = t2.blocking_session_id ) AS blocking_sql 
FROM
    sys.dm_tran_locks t1,
    sys.dm_os_waiting_tasks t2 
WHERE
    t1.lock_owner_address = t2.resource_address

This is not exactly showing you which rows are locked, but this may helpful to you.

You can check which statements are blocked by running this:

select cmd,* from sys.sysprocesses
where blocked > 0

It will also tell you what each block is waiting on. So you can trace that all the way up to see which statement caused the first block that caused the other blocks.

Edit to add comment from @MikeBlandford:

The blocked column indicates the spid of the blocking process. You can run kill {spid} to fix it.

You can also use the built-in sp_who2 stored procedure to get current blocked and blocking processes on a SQL Server instance. Typically you'd run this alongside a SQL Profiler instance to find a blocking process and look at the most recent command that spid issued in profiler.