Performance – SQLpowered.com

Get adhoc query plans without reuse

Jan Dvořák — Fri, 09 Mar 2018 14:12:03 +0000

SELECT 
	cp.usecounts, text querytext, cp.size_in_bytes/1024 size, plan_handle
FROM sys.dm_exec_cached_plans AS cp
	 CROSS APPLY sys.dm_exec_sql_text(plan_handle)
WHERE cp.cacheobjtype = N'Compiled Plan' AND 
	  cp.objtype = N'Adhoc' AND 
	  cp.usecounts = 1
ORDER BY querytext
GO

Flush plan cache for single database

Jan Dvořák — Fri, 09 Mar 2018 14:05:18 +0000

DECLARE @DbId INT
SET @DbId = DB_ID('DBNAME') 
DBCC FLUSHPROCINDB(@DbId)

Get CPU usage from Ring Buffer

Jan Dvořák — Fri, 09 Mar 2018 13:25:53 +0000

DECLARE @Now BIGINT
SELECT  @Now = ms_ticks FROM sys.dm_os_sys_info 

SELECT  DATEADD(ms, -1 * ( @Now - [timestamp] ), GETDATE()) AS EventTime,
        SQLService, 
        Idle,
        100 - Idle - SQLService AS NonSqlProcesses
FROM    ( SELECT    record.value('(./Record/@id)[1]', 'INT') AS record_id,
                    record.value('(./Record/SchedulerMonitorEvent/SystemHealth/SystemIdle)[1]', 'INT') AS Idle,
                    record.value('(./Record/SchedulerMonitorEvent/SystemHealth/ProcessUtilization)[1]', 'INT') AS SQLService, 
                    timestamp
          FROM      ( SELECT    timestamp, CONVERT(XML, record) AS record
                      FROM      sys.dm_os_ring_buffers
                      WHERE     ring_buffer_type = N'RING_BUFFER_SCHEDULER_MONITOR'
                                AND record LIKE '%%'
                    ) AS x
        ) AS y
ORDER BY 1 DESC

Listing Ring Buffer record types:

SELECT RecordType, COUNT(*)
FROM 
    (
        SELECT CAST(record as xml).value('(//Record/@type)[1]', 'varchar(30)') AS RecordType
        FROM sys.dm_os_ring_buffers
    ) rb
GROUP BY RecordType

Batch Requests/sec

Jan Dvořák — Fri, 09 Mar 2018 13:23:36 +0000

DECLARE @Batches INT
DECLARE @Delay CHAR(8)
DECLARE @SecToCalc INT

-- set seconds to calculate average
SET @SecToCalc = 5

SET @Delay = '00:00:' + CAST(@SecToCalc AS CHAR(2))

SELECT 
    @Batches = cntr_value 
FROM sys.dm_os_performance_counters
WHERE RTRIM(counter_name) = 'Batch Requests/sec'

WAITFOR DELAY @Delay

SELECT
    ( cntr_value - @Batches ) / CAST(@SecToCalc AS FLOAT) AS 'Batch Requests/sec'
FROM sys.dm_os_performance_counters
WHERE RTRIM(counter_name) = 'Batch Requests/sec'
GO

Get I/O statistics for data and log files

Jan Dvořák — Fri, 09 Mar 2018 13:20:55 +0000

SELECT
	LEFT ([mf].[physical_name], 2) AS [DriveLetter],
	DB_NAME ([vfs].[database_id]) AS [Database],
    [mf].[physical_name] [PhysicalName],
	[vfs].[size_on_disk_bytes] / 1024 / 1024 [FileSizeMB],
	[vfs].[io_stall],
	[vfs].[io_stall_read_ms], 
	CAST([io_stall_read_ms] / ( 1.0 + [num_of_reads] ) as numeric(10,1)) as 'avg_read_stall_ms',
	[vfs].[io_stall_write_ms],
	CAST([io_stall_write_ms] / ( 1.0 + [num_of_writes] ) as numeric(10,1)) as 'avg_write_stall_ms',
    [io_stall_read_ms] + [io_stall_write_ms] as [io_stalls],
    [num_of_reads] + [num_of_writes] as [total_io],
	CAST(([io_stall_read_ms]+[io_stall_write_ms]) / ( 1.0 + [num_of_reads] + [num_of_writes]) as numeric(10,1)) as 'avg_io_stall_ms',
	[TotalLatency] = CASE 
						WHEN [vfs].[num_of_reads] = 0 AND [vfs].[num_of_writes] = 0 THEN 0 
						ELSE [vfs].[io_stall] / ([vfs].[num_of_reads] + [vfs].[num_of_writes])
					END,
    [ReadLatency] = CASE 
						WHEN [vfs].[num_of_reads] = 0 THEN 0 
						ELSE [vfs].[io_stall_read_ms] / [vfs].[num_of_reads]
					END,
    [WriteLatency] = CASE 
						WHEN [vfs].[num_of_writes] = 0 THEN 0 
						ELSE [vfs].[io_stall_write_ms] / [vfs].[num_of_writes] 
					END,
    [vfs].[num_of_reads] [NumOfReads],
	[vfs].[num_of_bytes_read] [NumOfBytesRead],
	[AvgBytesPerRead] = CASE 
							WHEN [vfs].[num_of_reads] = 0 THEN 0 
							ELSE [vfs].[num_of_bytes_read] / [vfs].[num_of_reads] 
						END,
    [vfs].[num_of_writes] [NumOfWrites],
	[vfs].[num_of_bytes_written] [NumOfBytesWritten],
	[AvgBytesPerWrite] = CASE 
							WHEN [vfs].[io_stall_write_ms] = 0 THEN 0 
							ELSE [vfs].[num_of_bytes_written] / [vfs].[num_of_writes] 
						 END,
    [AvgBytedPerIO] = CASE 
							WHEN [vfs].[num_of_reads] = 0 AND [vfs].[num_of_writes] = 0 THEN 0 
							ELSE ([vfs].[num_of_bytes_read] + [vfs].[num_of_bytes_written]) / ([vfs].[num_of_reads] + [vfs].[num_of_writes]) 
						END
FROM [sys].[dm_io_virtual_file_stats] (NULL, NULL) [vfs]
	INNER JOIN [sys].[master_files] [mf] ON [vfs].[database_id] = [mf].[database_id] AND [vfs].[file_id] = [mf].[file_id]
ORDER BY [TotalLatency] DESC
GO

Wait Statistics Overview

Jan Dvořák — Fri, 09 Mar 2018 13:20:26 +0000

WITH [WaitStats] AS
(
	SELECT
        [wait_type],
        [wait_time_ms] / 1000.0 [WaitTimeSec],
        ([wait_time_ms] - [signal_wait_time_ms]) / 1000.0 [ResourcesWaitTimeSec],
        [signal_wait_time_ms] / 1000.0 [SignalWaitTimeSec],
        [waiting_tasks_count] [WaitingTasksCount],
        100.0 * [wait_time_ms] / SUM ([wait_time_ms]) OVER() [WaitPercentage],
        ROW_NUMBER() OVER(ORDER BY [wait_time_ms] DESC) [Rows],
		CASE
			WHEN [wait_type] 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', N'SP_SERVER_DIAGNOSTICS_SLEEP' ) THEN 1
			ELSE 0
		END IsSystemWaitType
    FROM [sys].[dm_os_wait_stats]
    )
SELECT
    [ws1].[wait_type] AS [WaitType],
    CAST([ws1].[WaitTimeSec] AS DECIMAL(12, 2)) [WaitTimeSec],
    CAST([ws1].[ResourcesWaitTimeSec] AS DECIMAL(12, 2)) [ResourcesWaitTimeSec],
    CAST([ws1].[SignalWaitTimeSec] AS DECIMAL(12, 2)) [SignalWaitTimeSec],
    [ws1].[WaitingTasksCount],
    CAST([ws1].[WaitPercentage] AS DECIMAL(12, 2)) [WaitPercentage],
    CASE
		WHEN [ws1].[WaitingTasksCount] > 0 THEN CAST(([ws1].[WaitTimeSec] / [ws1].[WaitingTasksCount]) AS DECIMAL(12, 2))
		ELSE 0
	END [AvgWaitTimeSec],
    CASE
		WHEN [ws1].[WaitingTasksCount] > 0 THEN CAST(([ws1].[ResourcesWaitTimeSec] / [ws1].[WaitingTasksCount]) AS DECIMAL(12, 2))
		ELSE 0
	END [AvgResourcesWaitTimeSec],
    CASE
		WHEN [ws1].[WaitingTasksCount] > 0 THEN CAST(([ws1].[SignalWaitTimeSec] / [ws1].[WaitingTasksCount]) AS DECIMAL(12, 2))
		ELSE 0
	END [AvgSignalWaitTimeSec]
FROM [WaitStats] AS [ws1]
WHERE [ws1].[IsSystemWaitType] = 0
GROUP BY [ws1].[IsSystemWaitType], [ws1].[Rows], [ws1].[wait_type], [ws1].[WaitTimeSec], [ws1].[ResourcesWaitTimeSec], [ws1].[SignalWaitTimeSec], [ws1].[WaitingTasksCount], [ws1].[WaitPercentage]
HAVING [ws1].[WaitTimeSec] > 0
ORDER BY [ws1].[WaitTimeSec] DESC
GO

Statistics overview with modifications, rows and age

Jan Dvořák — Fri, 09 Mar 2018 08:32:02 +0000

SELECT              
	[sc].[name] [SchemaName],
	[t].[name] [TableName],
	[s].[name] [StatisticsName],
	[ddsp].[modification_counter] [Modifications],
	[ddsp].[rows] [Rows],
	[ddsp].[rows_sampled] [RowsSampled],
	DATEDIFF(DAY, STATS_DATE([ddsp].[object_id], [ddsp].[stats_id]), GETDATE()) [AgeDays]
FROM [sys].[stats] [s]
	CROSS APPLY [sys].[dm_db_stats_properties]([s].[object_id], [s].[stats_id]) [ddsp]
	INNER JOIN [sys].[tables] [t] ON [t].[object_id] = [s].[object_id]
	INNER JOIN [sys].[schemas] [sc] ON [sc].[schema_id] = [t].[schema_id]
WHERE [sc].[name] <> 'sys' 
ORDER BY [SchemaName], [TableName], [StatisticsName]