/* ########################################################################################################## */
-- Get CPU utilization by database (Query 34) (CPU Usage by Database)
WITH DB_CPU_Stats
AS
(SELECT pa.DatabaseID, DB_Name(pa.DatabaseID) AS [Database Name], SUM(qs.total_worker_time/1000) AS [CPU_Time_Ms]
 FROM sys.dm_exec_query_stats AS qs WITH (NOLOCK)
 CROSS APPLY (SELECT CONVERT(int, value) AS [DatabaseID] 
              FROM sys.dm_exec_plan_attributes(qs.plan_handle)
              WHERE attribute = N'dbid') AS pa
 GROUP BY DatabaseID)
SELECT ROW_NUMBER() OVER(ORDER BY [CPU_Time_Ms] DESC) AS [CPU Rank],
       [Database Name], [CPU_Time_Ms] AS [CPU Time (ms)], 
       CAST([CPU_Time_Ms] * 1.0 / SUM([CPU_Time_Ms]) OVER() * 100.0 AS DECIMAL(5, 2)) AS [CPU Percent]
FROM DB_CPU_Stats
WHERE DatabaseID <> 32767 -- ResourceDB
ORDER BY [CPU Rank] OPTION (RECOMPILE);
------
/* ########################################################################################################## */
-- Get Average Task Counts (run multiple times)  (Query 39) (Avg Task Counts)
SELECT AVG(current_tasks_count) AS [Avg Task Count], 
AVG(work_queue_count) AS [Avg Work Queue Count],
AVG(runnable_tasks_count) AS [Avg Runnable Task Count],
AVG(pending_disk_io_count) AS [Avg Pending DiskIO Count]
FROM sys.dm_os_schedulers WITH (NOLOCK)
WHERE scheduler_id < 255 OPTION (RECOMPILE);
------

-- Sustained values above 10 suggest further investigation in that area
-- High Avg Task Counts are often caused by blocking/deadlocking or other resource contention

-- Sustained values above 1 suggest further investigation in that area
-- High Avg Runnable Task Counts are a good sign of CPU pressure
-- High Avg Pending DiskIO Counts are a sign of disk pressure

-- How to Do Some Very Basic SQL Server Monitoring
-- https://www.sqlskills.com/blogs/glenn/how-to-do-some-very-basic-sql-server-monitoring/
/* ########################################################################################################## */
-- Get CPU Utilization History for last 256 minutes (in one minute intervals)  (Query 41) (CPU Utilization History)
DECLARE @ts_now bigint = (SELECT cpu_ticks/(cpu_ticks/ms_ticks) FROM sys.dm_os_sys_info WITH (NOLOCK)); 

SELECT TOP(256) SQLProcessUtilization AS [SQL Server Process CPU Utilization], 
               SystemIdle AS [System Idle Process], 
               100 - SystemIdle - SQLProcessUtilization AS [Other Process CPU Utilization], 
               DATEADD(ms, -1 * (@ts_now - [timestamp]), GETDATE()) AS [Event Time] 
FROM (SELECT record.value('(./Record/@id)[1]', 'int') AS record_id, 
			record.value('(./Record/SchedulerMonitorEvent/SystemHealth/SystemIdle)[1]', 'int') 
			AS [SystemIdle], 
			record.value('(./Record/SchedulerMonitorEvent/SystemHealth/ProcessUtilization)[1]', 'int') 
			AS [SQLProcessUtilization], [timestamp] 
	  FROM (SELECT [timestamp], CONVERT(xml, record) AS [record] 
			FROM sys.dm_os_ring_buffers WITH (NOLOCK)
			WHERE ring_buffer_type = N'RING_BUFFER_SCHEDULER_MONITOR' 
			AND record LIKE N'%<SystemHealth>%') AS x) AS y 

--WHERE SQLProcessUtilization > 70	-- >70 %

ORDER BY record_id DESC OPTION (RECOMPILE);
------

-- Look at the trend over the entire period 
-- Also look at high sustained 'Other Process' CPU Utilization values
/* ########################################################################################################## */
-- Get top total worker time queries for entire instance (Query 42) (Top Worker Time Queries)
SELECT TOP(50) DB_NAME(t.[dbid]) AS [Database Name], 
REPLACE(REPLACE(LEFT(t.[text], 255), CHAR(10),''), CHAR(13),'') AS [Short Query Text],  
qs.total_worker_time AS [Total Worker Time], qs.min_worker_time AS [Min Worker Time],
qs.total_worker_time/qs.execution_count AS [Avg Worker Time], 
qs.max_worker_time AS [Max Worker Time], 
qs.min_elapsed_time AS [Min Elapsed Time], 
qs.total_elapsed_time/qs.execution_count AS [Avg Elapsed Time], 
qs.max_elapsed_time AS [Max Elapsed Time],
qs.min_logical_reads AS [Min Logical Reads],
qs.total_logical_reads/qs.execution_count AS [Avg Logical Reads],
qs.max_logical_reads AS [Max Logical Reads], 
qs.execution_count AS [Execution Count], qs.creation_time AS [Creation Time]
,t.[text] AS [Query Text], qp.query_plan AS [Query Plan] -- uncomment out these columns if not copying results to Excel
FROM sys.dm_exec_query_stats AS qs WITH (NOLOCK)
CROSS APPLY sys.dm_exec_sql_text(plan_handle) AS t 
CROSS APPLY sys.dm_exec_query_plan(plan_handle) AS qp 
ORDER BY qs.total_worker_time DESC OPTION (RECOMPILE);
------


-- Helps you find the most expensive queries from a CPU perspective across the entire instance
-- Can also help track down parameter sniffing issues
/* ########################################################################################################## */
-- Top Cached SPs By Total Worker time. Worker time relates to CPU cost  (Query 57) (SP Worker Time)
SELECT TOP(25) p.name AS [SP Name], qs.total_worker_time AS [TotalWorkerTime], 
qs.total_worker_time/qs.execution_count AS [AvgWorkerTime], qs.execution_count, 
ISNULL(qs.execution_count/DATEDIFF(Minute, qs.cached_time, GETDATE()), 0) AS [Calls/Minute],
qs.total_elapsed_time, qs.total_elapsed_time/qs.execution_count 
AS [avg_elapsed_time], qs.cached_time
FROM sys.procedures AS p WITH (NOLOCK)
INNER JOIN sys.dm_exec_procedure_stats AS qs WITH (NOLOCK)
ON p.[object_id] = qs.[object_id]
WHERE qs.database_id = DB_ID()
AND DATEDIFF(Minute, qs.cached_time, GETDATE()) > 0
ORDER BY qs.total_worker_time DESC OPTION (RECOMPILE);
------

-- This helps you find the most expensive cached stored procedures from a CPU perspective
-- You should look at this if you see signs of CPU pressure
/* ########################################################################################################## */