List Blocking Processes In SQL Server
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We use this quick script to list those processes that are blocking other processes in SQL server. What you do with the information is up to you, but we suggest checking to ensure you're only locking when you need to (SET READ UNCOMMITTED or use NOLOCK, ROWLOCK hints if appropriate), and we also suggest you review your SQL setup: is your hardware fast enough? Have you separated out your logging, data and tempDB files onto separate volumes? Usage:
ListBlocking [@KillOrphanedProcesses = 0]If
@KillOrphanedProcessesis set to 1 then the script will attempt to kill orphaned processes.
IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[ListBlocking]') AND type in (N'P', N'PC')) EXEC dbo.sp_executesql @statement = N'CREATE PROCEDURE [dbo].[ListBlocking] AS' GO /*=================================================================== Description: Wrapper to sp_who2 to show only those processes that are blocking. Please see http://support.microsoft.com/kb/224453 for more info on locking. ===================================================================*/ ALTER procedure ListBlocking ( @KillOrphanedProcesses bit = 0 ) as IF OBJECT_ID('tempdb..#Process') IS NOT NULL drop table #Process IF OBJECT_ID('tempdb..#BlockingProcess') IS NOT NULL drop table #BlockingProcess create table #Process ( SPID int, Status varchar(500), Login varchar(500), Hostname varchar(500), BlkBy varchar(50), DBName varchar(500), Command varchar(500), CPUTime int, DiskIO int, LastBatch varchar(500), ProgramName varchar(500), SPID2 int, RequestId int ) CREATE TABLE #BlockingProcess ( BlockingProcessID int IDENTITY(1,1), ProcessID varchar(20), EventType varchar(100), Parameters varchar(100), EventInfo varchar(500), CPUTime int, DiskIO int, TransactionCount int ) DECLARE @BlockingPID varchar(20), @CPUTime int, @DiskIO int, @TransactionCount int -- Let SQL Server get us a list of what's going on SET NOCOUNT ON insert into #Process exec sp_who2 -- From this list of what's going on, get those items that are blocked, and loop through them DECLARE ProcessCursor CURSOR FAST_FORWARD FOR SELECT BlkBy, SUM(CPUTime) as CPUTime, SUM(DiskIO) as DiskIO FROM #Process WHERE ISNULL(BlkBy,'') <> '' GROUP BY BlkBy OPEN ProcessCursor FETCH NEXT FROM ProcessCursor INTO @BlockingPID, @CPUTime, @DiskIO WHILE @@FETCH_STATUS = 0 BEGIN -- Only valid PIDs if ISNULL(@BlockingPID, '') <> '' and @BlockingPID <> '0' AND @BlockingPID <> ' .' BEGIN -- For each blocked process get what information we can on the process and what's blocking it SET @TransactionCount = 0 -- -2 = The blocking resource is owned by an orphaned distributed transaction. IF SUBSTRING(@BlockingPID, 1, 2) = '-2' BEGIN -- For orphaned processes we need to get the Unit of work if we're to do anything with it DECLARE @UnitOfWork varchar(50) select top 1 @UnitOfWork = ISNULL(req_transactionUOW, '') from master..syslockinfo where req_spid = -2 if @KillOrphanedProcesses = 1 BEGIN if @UnitOfWork <> '' exec('KILL ''' + @UnitOfWork + '''') INSERT INTO #BlockingProcess (EventType, Parameters, EventInfo) VALUES('', '', '- Killed UOW ' + @UnitOfWork + ' -') END ELSE BEGIN INSERT INTO #BlockingProcess (EventType, Parameters, EventInfo) VALUES('', '', '- Orphaned. UOW = ' + @UnitOfWork + ' -') END END -- -3 = The blocking resource is owned by a deferred recovery transaction. ELSE IF SUBSTRING(@BlockingPID, 1, 2) = '-3' BEGIN INSERT INTO #BlockingProcess (EventType, Parameters, EventInfo) VALUES('', '', '- deferred recovery transaction -') END -- -4 = Session ID of the blocking latch owner could not be determined at this -- time because of internal latch state transitions. ELSE IF SUBSTRING(@BlockingPID, 1, 2) = '-4' BEGIN INSERT INTO #BlockingProcess (EventType, Parameters, EventInfo) VALUES('', '', '- Latch owner could not be determined -') END -- Nothing unusual here. A process is being blocked by another processes, so let's get the -- info on the process that's doing the blocking ELSE BEGIN SELECT @TransactionCount = open_tran FROM master.sys.sysprocesses WHERE SPID=@BlockingPID INSERT INTO #BlockingProcess (EventType, Parameters, EventInfo) EXEC ('DBCC INPUTBUFFER(' + @BlockingPID + ') WITH NO_INFOMSGS') END -- Add some aggregate info on the blocking processes UPDATE #BlockingProcess SET ProcessID = @BlockingPID, CPUTime = @CPUTime, DiskIO = @DiskIO, TransactionCount = @TransactionCount WHERE BlockingProcessID = SCOPE_IDENTITY() END FETCH NEXT FROM ProcessCursor INTO @BlockingPID, @CPUTime, @DiskIO END CLOSE ProcessCursor DEALLOCATE ProcessCursor -- Display the results SELECT ProcessID, EventInfo, TransactionCount, CPUTime, DiskIO FROM #BlockingProcess SET NOCOUNT OFFSpring Framework
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