Top 5 Waiting Tasks by Percent

Use below script to determine the Top 5 waiting tasks and sorted by percent of use in the top 5

 

 

WITH [Waits] AS

                (SELECT

                                [wait_type],

                                [wait_time_ms] / 1000.0 AS [WaitS],

                                ([wait_time_ms] - [signal_wait_time_ms]) / 1000.0 AS [ResourceS],

                                [signal_wait_time_ms] / 1000.0 AS [SignalS],

                                [waiting_tasks_count] AS [WaitCount],

                                100.0 * [wait_time_ms] / SUM ([wait_time_ms]) OVER() AS [Percentage],

                                ROW_NUMBER() OVER(ORDER BY [wait_time_ms] DESC) AS [RowNum]

                FROM sys.dm_os_wait_stats

                WHERE [wait_type] NOT IN (

                                N’CLR_SEMAPHORE’,    N’LAZYWRITER_SLEEP’,

                                N’RESOURCE_QUEUE’,   N’SQLTRACE_BUFFER_FLUSH’,

                                N’SLEEP_TASK’,       N’SLEEP_SYSTEMTASK’,

                                N’WAITFOR’,          N’HADR_FILESTREAM_IOMGR_IOCOMPLETION’,

                                N’CHECKPOINT_QUEUE’, N’REQUEST_FOR_DEADLOCK_SEARCH’,

                                N’XE_TIMER_EVENT’,   N’XE_DISPATCHER_JOIN’,

                                N’LOGMGR_QUEUE’,     N’FT_IFTS_SCHEDULER_IDLE_WAIT’,

                                N’BROKER_TASK_STOP’, N’CLR_MANUAL_EVENT’,

                                N’CLR_AUTO_EVENT’,   N’DISPATCHER_QUEUE_SEMAPHORE’,

                                N’TRACEWRITE’,       N’XE_DISPATCHER_WAIT’,

                                N’BROKER_TO_FLUSH’,  N’BROKER_EVENTHANDLER’,

                                N’FT_IFTSHC_MUTEX’,  N’SQLTRACE_INCREMENTAL_FLUSH_SLEEP’,

                                N’DIRTY_PAGE_POLL’)

                )

SELECT

                [W1].[wait_type] AS [WaitType],

                CAST ([W1].[WaitS] AS DECIMAL(14, 2)) AS [Wait_S],

                CAST ([W1].[ResourceS] AS DECIMAL(14, 2)) AS [Resource_S],

                CAST ([W1].[SignalS] AS DECIMAL(14, 2)) AS [Signal_S],

                [W1].[WaitCount] AS [WaitCount],

                CAST ([W1].[Percentage] AS DECIMAL(4, 2)) AS [Percentage],

                CAST (([W1].[WaitS] / [W1].[WaitCount]) AS DECIMAL (14, 4)) AS [AvgWait_S],

                CAST (([W1].[ResourceS] / [W1].[WaitCount]) AS DECIMAL (14, 4)) AS [AvgRes_S],

                CAST (([W1].[SignalS] / [W1].[WaitCount]) AS DECIMAL (14, 4)) AS [AvgSig_S]

FROM [Waits] AS [W1]

INNER JOIN [Waits] AS [W2]

                ON [W2].[RowNum] <= [W1].[RowNum]

GROUP BY [W1].[RowNum], [W1].[wait_type], [W1].[WaitS],

                [W1].[ResourceS], [W1].[SignalS], [W1].[WaitCount], [W1].[Percentage]

HAVING SUM ([W2].[Percentage]) - [W1].[Percentage] < 95; -- percentage threshold

GO