使用DMV，诊断和调优DB性能。 查看等待统计信息，找出SQL Server慢在哪里： SELECT wait_type , SUM(wait_time_ms / 1000) AS [wait_time_s] FROM sys.dm_os_wait_stats DOWS WHERE wait_type NOT IN ( N'BROKER_EVENTHANDLER', N'BROKER_RECEIVE_WAITFOR', N'BROKER_TASK_STOP', N'BROKER_TO_FLUSH', N'BROKER_TRANSMITTER', N'CHECKPOINT_QUEUE', N'CHKPT', N'CLR_AUTO_EVENT', N'CLR_MANUAL_EVENT', N'CLR_SEMAPHORE', N'DBMIRROR_DBM_EVENT', N'DBMIRROR_EVENTS_QUEUE', N'DBMIRROR_WORKER_QUEUE', N'DBMIRRORING_CMD', N'DIRTY_PAGE_POLL', N'DISPATCHER_QUEUE_SEMAPHORE', N'EXECSYNC', N'FSAGENT', N'FT_IFTS_SCHEDULER_IDLE_WAIT', N'FT_IFTSHC_MUTEX', N'HADR_CLUSAPI_CALL', N'HADR_FILESTREAM_IOMGR_IOCOMPLETION', N'HADR_LOGCAPTURE_WAIT', N'HADR_NOTIFICATION_DEQUEUE', N'HADR_TIMER_TASK', N'HADR_WORK_QUEUE', N'KSOURCE_WAKEUP', N'LAZYWRITER_SLEEP', N'LOGMGR_QUEUE', N'ONDEMAND_TASK_QUEUE', N'PWAIT_ALL_COMPONENTS_INITIALIZED', N'QDS_PERSIST_TASK_MAIN_LOOP_SLEEP', N'QDS_CLEANUP_STALE_QUERIES_TASK_MAIN_LOOP_SLEEP', N'REQUEST_FOR_DEADLOCK_SEARCH', N'RESOURCE_QUEUE', N'SERVER_IDLE_CHECK', N'SLEEP_BPOOL_FLUSH', N'SLEEP_DBSTARTUP', N'SLEEP_DCOMSTARTUP', N'SLEEP_MASTERDBREADY', N'SLEEP_MASTERMDREADY', N'SLEEP_MASTERUPGRADED', N'SLEEP_MSDBSTARTUP', N'SLEEP_SYSTEMTASK', N'SLEEP_TASK', N'SLEEP_TEMPDBSTARTUP', N'SNI_HTTP_ACCEPT', N'SP_SERVER_DIAGNOSTICS_SLEEP', N'SQLTRACE_BUFFER_FLUSH', N'SQLTRACE_INCREMENTAL_FLUSH_SLEEP', N'SQLTRACE_WAIT_ENTRIES', N'WAIT_FOR_RESULTS', N'WAITFOR', N'WAITFOR_TASKSHUTDOWN', N'WAIT_XTP_HOST_WAIT', N'WAIT_XTP_OFFLINE_CKPT_NEW_LOG', N'WAIT_XTP_CKPT_CLOSE', N'XE_DISPATCHER_JOIN', N'XE_DISPATCHER_WAIT', N'XE_TIMER_EVENT') GROUP BY wait_type ORDER BY SUM(wait_time_ms) DESC 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'BROKER_EVENTHANDLER', N'BROKER_RECEIVE_WAITFOR', N'BROKER_TASK_STOP', N'BROKER_TO_FLUSH', N'BROKER_TRANSMITTER', N'CHECKPOINT_QUEUE', N'CHKPT', N'CLR_AUTO_EVENT', N'CLR_MANUAL_EVENT', N'CLR_SEMAPHORE', N'DBMIRROR_DBM_EVENT', N'DBMIRROR_EVENTS_QUEUE', N'DBMIRROR_WORKER_QUEUE', N'DBMIRRORING_CMD', N'DIRTY_PAGE_POLL', N'DISPATCHER_QUEUE_SEMAPHORE', N'EXECSYNC', N'FSAGENT', N'FT_IFTS_SCHEDULER_IDLE_WAIT', N'FT_IFTSHC_MUTEX', N'HADR_CLUSAPI_CALL', N'HADR_FILESTREAM_IOMGR_IOCOMPLETION', N'HADR_LOGCAPTURE_WAIT', N'HADR_NOTIFICATION_DEQUEUE', N'HADR_TIMER_TASK', N'HADR_WORK_QUEUE', N'KSOURCE_WAKEUP', N'LAZYWRITER_SLEEP', N'LOGMGR_QUEUE', N'ONDEMAND_TASK_QUEUE', N'PWAIT_ALL_COMPONENTS_INITIALIZED', N'QDS_PERSIST_TASK_MAIN_LOOP_SLEEP', N'QDS_CLEANUP_STALE_QUERIES_TASK_MAIN_LOOP_SLEEP', N'REQUEST_FOR_DEADLOCK_SEARCH', N'RESOURCE_QUEUE', N'SERVER_IDLE_CHECK', N'SLEEP_BPOOL_FLUSH', N'SLEEP_DBSTARTUP', N'SLEEP_DCOMSTARTUP', N'SLEEP_MASTERDBREADY', N'SLEEP_MASTERMDREADY', N'SLEEP_MASTERUPGRADED', N'SLEEP_MSDBSTARTUP', N'SLEEP_SYSTEMTASK', N'SLEEP_TASK', N'SLEEP_TEMPDBSTARTUP', N'SNI_HTTP_ACCEPT', N'SP_SERVER_DIAGNOSTICS_SLEEP', N'SQLTRACE_BUFFER_FLUSH', N'SQLTRACE_INCREMENTAL_FLUSH_SLEEP', N'SQLTRACE_WAIT_ENTRIES', N'WAIT_FOR_RESULTS', N'WAITFOR', N'WAITFOR_TASKSHUTDOWN', N'WAIT_XTP_HOST_WAIT', N'WAIT_XTP_OFFLINE_CKPT_NEW_LOG', N'WAIT_XTP_CKPT_CLOSE', N'XE_DISPATCHER_JOIN', N'XE_DISPATCHER_WAIT', N'XE_TIMER_EVENT') AND [waiting_tasks_count] > 0 ) SELECT MAX ([W1].[wait_type]) AS [WaitType], CAST (MAX ([W1].[WaitS]) AS DECIMAL (16,2)) AS [Wait_S], CAST (MAX ([W1].[ResourceS]) AS DECIMAL (16,2)) AS [Resource_S], CAST (MAX ([W1].[SignalS]) AS DECIMAL (16,2)) AS [Signal_S], MAX ([W1].[WaitCount]) AS [WaitCount], CAST (MAX ([W1].[Percentage]) AS DECIMAL (5,2)) AS [Percentage], CAST ((MAX ([W1].[WaitS]) / MAX ([W1].[WaitCount])) AS DECIMAL (16,4)) AS [AvgWait_S], CAST ((MAX ([W1].[ResourceS]) / MAX ([W1].[WaitCount])) AS DECIMAL (16,4)) AS [AvgRes_S], CAST ((MAX ([W1].[SignalS]) / MAX ([W1].[WaitCount])) AS DECIMAL (16,4)) AS [AvgSig_S] FROM [Waits] AS [W1] INNER JOIN [Waits] AS [W2] ON [W2].[RowNum] <= [W1].[RowNum] GROUP BY [W1].[RowNum] HAVING SUM ([W2].[Percentage]) - MAX ([W1].[Percentage]) < 95; -- percentage threshold GO 获取一段时间内累计的File reads： SELECT DB_NAME(mf.database_id) AS databaseName , mf.physical_name , divfs.num_of_reads , --other columns removed in this section. See Listing 6.14 for complete code GETDATE() AS baselineDate INTO #baseline FROM sys.dm_io_virtual_file_stats(NULL, NULL) AS divfs JOIN sys.master_files AS mf ON mf.database_id = divfs.database_id AND mf.file_id = divfs.file_id --过一段时间后执行下面的SQL WITH currentLine AS ( SELECT DB_NAME(mf.database_id) AS databaseName , mf.physical_name , num_of_reads , --other columms removed GETDATE() AS currentlineDate FROM sys.dm_io_virtual_file_stats(NULL, NULL) AS divfs JOIN sys.master_files AS mf ON mf.database_id = divfs.database_id AND mf.file_id = divfs.file_id ) SELECT currentLine.databaseName , currentLine.physical_name , --gets the time difference in milliseconds since the baseline was taken DATEDIFF(millisecond,baseLineDate,currentLineDate) AS elapsed_ms, --gets the change in time since the baseline was taken currentLine.num_of_reads - #baseline.num_of_reads AS num_of_reads --other columns removed FROM currentLine INNER JOIN #baseline ON #baseLine.databaseName = currentLine.databaseName AND #baseLine.physical_name = currentLine.physical_name 根据IP获取连接个数 -- Get a count of SQL connections by IP address SELECT dec.client_net_address , des.program_name , des.host_name , --des.login_name , COUNT(dec.session_id) AS connection_count FROM sys.dm_exec_sessions AS des INNER JOIN sys.dm_exec_connections AS dec ON des.session_id = dec.session_id -- WHERE LEFT(des.host_name, 2) = 'WK' GROUP BY dec.client_net_address , des.program_name , des.host_name -- des.login_name -- HAVING COUNT(dec.session_id) > 1 ORDER BY des.program_name, dec.client_net_address ; 查看谁在通过SSMS执行什么 SELECT dec.client_net_address , des.host_name , dest.text FROM sys.dm_exec_sessions des INNER JOIN sys.dm_exec_connections dec ON des.session_id = dec.session_id CROSS APPLY sys.dm_exec_sql_text(dec.most_recent_sql_handle) dest WHERE des.program_name LIKE 'Microsoft SQL Server Management Studio%' ORDER BY des.program_name , dec.client_net_address 查看当前session的session级别的设置 SELECT des.text_size , des.language , des.date_format , des.date_first , des.quoted_identifier , des.arithabort , des.ansi_null_dflt_on , des.ansi_defaults , des.ansi_warnings , des.ansi_padding , des.ansi_nulls , des.concat_null_yields_null , des.transaction_isolation_level , des.lock_timeout , des.deadlock_priority FROM sys.dm_exec_sessions des WHERE des.session_id = @@SPID 查看超过一个session的登录信息 SELECT login_name , COUNT(session_id) AS session_count FROM sys.dm_exec_sessions WHERE is_user_process = 1 GROUP BY login_name ORDER BY login_name 识别有context swithing的sessions信息 SELECT session_id , login_name , original_login_name FROM sys.dm_exec_sessions WHERE is_user_process = 1 AND login_name <> original_login_name 识别不活动的sessions DECLARE @days_old SMALLINT SELECT @days_old = 5 SELECT des.session_id , des.login_time , des.last_request_start_time , des.last_request_end_time , des.[status] , des.[program_name] , des.cpu_time , des.total_elapsed_time , des.memory_usage , des.total_scheduled_time , des.total_elapsed_time , des.reads , des.writes , des.logical_reads , des.row_count , des.is_user_process FROM sys.dm_exec_sessions des INNER JOIN sys.dm_tran_session_transactions dtst ON des.session_id = dtst.session_id WHERE des.is_user_process = 1 AND DATEDIFF(dd, des.last_request_end_time, GETDATE()) > @days_old AND des.status != 'Running' ORDER BY des.last_request_end_time 识别孤立事务引起的闲置sessions SELECT des.session_id , des.login_time , des.last_request_start_time , des.last_request_end_time , des.host_name , des.login_name FROM sys.dm_exec_sessions des INNER JOIN sys.dm_tran_session_transactions dtst ON des.session_id = dtst.session_id LEFT JOIN sys.dm_exec_requests der ON dtst.session_id = der.session_id WHERE der.session_id IS NULL ORDER BY des.session_id 查看当前活动请求的执行计划、CPU消耗等 SELECT der.session_id , DB_NAME(der.database_id) AS database_name , deqp.query_plan , SUBSTRING(dest.text, der.statement_start_offset / 2, ( CASE WHEN der.statement_end_offset = -1 THEN DATALENGTH(dest.text) ELSE der.statement_end_offset END - der.statement_start_offset ) / 2) AS [statement executing] , der.cpu_time --der.granted_query_memory --der.wait_time --der.total_elapsed_time --der.reads FROM sys.dm_exec_requests der INNER JOIN sys.dm_exec_sessions des ON des.session_id = der.session_id CROSS APPLY sys.dm_exec_sql_text(der.sql_handle) dest CROSS APPLY sys.dm_exec_query_plan(der.plan_handle) deqp WHERE des.is_user_process = 1 AND der.session_id <> @@spid ORDER BY der.cpu_time DESC ; -- ORDER BY der.granted_query_memory DESC ; -- ORDER BY der.wait_time DESC; -- ORDER BY der.total_elapsed_time DESC; -- ORDER BY der.reads DESC; 查看当前谁在运行什么 -- Who is running what at this instant SELECT dest.text AS [Command text] , des.login_time , des.[host_name] , des.[program_name] , der.session_id , dec.client_net_address , der.status , der.command , DB_NAME(der.database_id) AS DatabaseName FROM sys.dm_exec_requests der INNER JOIN sys.dm_exec_connections dec ON der.session_id = dec.session_id INNER JOIN sys.dm_exec_sessions des ON des.session_id = der.session_id CROSS APPLY sys.dm_exec_sql_text(sql_handle) AS dest WHERE des.is_user_process = 1 比SP_WHO2更好的SQL SELECT des.session_id , des.status , des.login_name , des.[HOST_NAME] , der.blocking_session_id , DB_NAME(der.database_id) AS database_name , der.command , des.cpu_time , des.reads , des.writes , dec.last_write , des.[program_name] , der.wait_type , der.wait_time , der.last_wait_type , der.wait_resource , CASE des.transaction_isolation_level WHEN 0 THEN 'Unspecified' WHEN 1 THEN 'ReadUncommitted' WHEN 2 THEN 'ReadCommitted' WHEN 3 THEN 'Repeatable' WHEN 4 THEN 'Serializable' WHEN 5 THEN 'Snapshot' END AS transaction_isolation_level , OBJECT_NAME(dest.objectid, der.database_id) AS OBJECT_NAME , SUBSTRING(dest.text, der.statement_start_offset / 2, ( CASE WHEN der.statement_end_offset = -1 THEN DATALENGTH(dest.text) ELSE der.statement_end_offset END - der.statement_start_offset ) / 2) AS [executing statement] , deqp.query_plan FROM sys.dm_exec_sessions des LEFT JOIN sys.dm_exec_requests der ON des.session_id = der.session_id LEFT JOIN sys.dm_exec_connections dec ON des.session_id = dec.session_id CROSS APPLY sys.dm_exec_sql_text(der.sql_handle) dest CROSS APPLY sys.dm_exec_query_plan(der.plan_handle) deqp WHERE des.session_id <> @@SPID ORDER BY des.session_id 清除指定数据库的计划缓存 --Determine the id of your database DECLARE @intDBID INTEGER SET @intDBID = ( SELECT dbid FROM master.dbo.sysdatabases WHERE name = 'mydatabasename' ) --Flush the procedure cache for your database DBCC FLUSHPROCINDB (@intDBID) Retrieving the text for a currently executing ad hoc query SELECT dest.text , dest.dbid , dest.objectid FROM sys.dm_exec_requests AS der CROSS APPLY sys.dm_exec_sql_text(der.sql_handle) AS dest WHERE session_id = @@spid ; Retrieving the text for a currently executing batch SELECT dest.text FROM sys.dm_exec_requests AS der CROSS APPLY sys.dm_exec_sql_text(der.sql_handle) AS dest WHERE session_id <> @@spid AND text LIKE '%waitfor%' ; Returning the text of an executing stored procedure SELECT dest.dbid , dest.objectid , dest.encrypted , dest.text FROM sys.dm_exec_requests AS der CROSS APPLY sys.dm_exec_sql_text(der.sql_handle) AS dest WHERE objectid = object_id('test', 'p'); Parsing the SQL text using statement_start_offset and statement_end_offset SELECT der.statement_start_offset , der.statement_end_offset , SUBSTRING(dest.text, der.statement_start_offset / 2, ( CASE WHEN der.statement_end_offset = -1 THEN DATALENGTH(dest.text) ELSE der.statement_end_offset END - der.statement_start_offset ) / 2) AS statement_executing , dest.text AS [full statement code] FROM sys.dm_exec_requests der INNER JOIN sys.dm_exec_sessions des ON des.session_id = der.session_id CROSS APPLY sys.dm_exec_sql_text(der.sql_handle) dest WHERE des.is_user_process = 1 AND der.session_id <> @@spid ORDER BY der.session_id ; Investigating offsets. WAITFOR DELAY '00:01' ; BEGIN TRANSACTION -- WAITFOR DELAY '00:01' ; INSERT INTO AdventureWorks.Production.ProductCategory ( Name, ModifiedDate ) VALUES ( 'Reflectors', GETDATE() ) ROLLBACK TRANSACTION SELECT Name , ModifiedDate FROM AdventureWorks.Production.ProductCategory WHERE Name = 'Reflectors' ; -- WAITFOR DELAY '00:01' ; Requests by CPU consumption SELECT der.session_id , DB_NAME(der.database_id) AS database_name , deqp.query_plan , SUBSTRING(dest.text, der.statement_start_offset / 2, ( CASE WHEN der.statement_end_offset = -1 THEN DATALENGTH(dest.text) ELSE der.statement_end_offset END - der.statement_start_offset ) / 2) AS [statement executing] , der.cpu_time --der.granted_query_memory --der.wait_time --der.total_elapsed_time --der.reads FROM sys.dm_exec_requests der INNER JOIN sys.dm_exec_sessions des ON des.session_id = der.session_id CROSS APPLY sys.dm_exec_sql_text(der.sql_handle) dest CROSS APPLY sys.dm_exec_query_plan(der.plan_handle) deqp WHERE des.is_user_process = 1 AND der.session_id <> @@spid ORDER BY der.cpu_time DESC ; -- ORDER BY der.granted_query_memory DESC ; -- ORDER BY der.wait_time DESC; -- ORDER BY der.total_elapsed_time DESC; -- ORDER BY der.reads DESC; Who is running what -- Who is running what at this instant SELECT dest.text AS [Command text] , des.login_time , des.[host_name] , des.[program_name] , der.session_id , dec.client_net_address , der.status , der.command , DB_NAME(der.database_id) AS DatabaseName FROM sys.dm_exec_requests der INNER JOIN sys.dm_exec_connections dec ON der.session_id = dec.session_id INNER JOIN sys.dm_exec_sessions des ON des.session_id = der.session_id CROSS APPLY sys.dm_exec_sql_text(sql_handle) AS dest WHERE des.is_user_process = 1 Flushing the cache of plans belonging to a particular database. --Determine the id of your database DECLARE @intDBID INTEGER SET @intDBID = ( SELECT dbid FROM master.dbo.sysdatabases WHERE name = 'mydatabasename' ) --Flush the procedure cache for your database DBCC FLUSHPROCINDB (@intDBID) Retrieving the query plan for a cached stored procedure CREATE PROCEDURE ShowQueryText AS SELECT TOP 10 object_id , name FROM sys.objects ; --waitfor delay '00:00:00' SELECT TOP 10 object_id , name FROM sys.objects ; SELECT TOP 10 object_id , name FROM sys.procedures ; GO EXEC dbo.ShowQueryText ; GO SELECT deqp.dbid , deqp.objectid , deqp.encrypted , deqp.query_plan FROM sys.dm_exec_query_stats deqs CROSS APPLY sys.dm_exec_query_plan(deqs.plan_handle) AS deqp WHERE objectid = OBJECT_ID('ShowQueryText', 'p') ; Viewing the sql_handle and plan_handle. SELECT deqs.plan_handle , deqs.sql_handle , execText.text FROM sys.dm_exec_query_stats deqs CROSS APPLY sys.dm_exec_sql_text(deqs.plan_handle) AS execText WHERE execText.text LIKE 'CREATE PROCEDURE ShowQueryText%' Extracting the SQL text for individual queries in a batch. SELECT CHAR(13) + CHAR(10) + CASE WHEN deqs.statement_start_offset = 0 AND deqs.statement_end_offset = -1 THEN '-- see objectText column--' ELSE '-- query --' + CHAR(13) + CHAR(10) + SUBSTRING(execText.text, deqs.statement_start_offset / 2, ( ( CASE WHEN deqs.statement_end_offset = -1 THEN DATALENGTH(execText.text) ELSE deqs.statement_end_offset END ) - deqs.statement_start_offset ) / 2) END AS queryText , deqp.query_plan FROM sys.dm_exec_query_stats deqs CROSS APPLY sys.dm_exec_sql_text(deqs.plan_handle) AS execText CROSS APPLY sys.dm_exec_query_plan(deqs.plan_handle) deqp WHERE execText.text LIKE 'CREATE PROCEDURE ShowQueryText%' Returning the plan using sys.dm_exec_text_query_plan. SELECT deqp.dbid , deqp.objectid , CAST(detqp.query_plan AS XML) AS singleStatementPlan , deqp.query_plan AS batch_query_plan , --this won't actually work in all cases because nominal plans aren't -- cached, so you won't see a plan for waitfor if you uncomment it ROW_NUMBER() OVER ( ORDER BY Statement_Start_offset ) AS query_position , CASE WHEN deqs.statement_start_offset = 0 AND deqs.statement_end_offset = -1 THEN '-- see objectText column--' ELSE '-- query --' + CHAR(13) + CHAR(10) + SUBSTRING(execText.text, deqs.statement_start_offset / 2, ( ( CASE WHEN deqs.statement_end_offset = -1 THEN DATALENGTH(execText.text) ELSE deqs.statement_end_offset END ) - deqs.statement_start_offset ) / 2) END AS queryText FROM sys.dm_exec_query_stats deqs CROSS APPLY sys.dm_exec_text_query_plan(deqs.plan_handle, deqs.statement_start_offset, deqs.statement_end_offset) AS detqp CROSS APPLY sys.dm_exec_query_plan(deqs.plan_handle) AS deqp CROSS APPLY sys.dm_exec_sql_text(deqs.plan_handle) AS execText WHERE deqp.objectid = OBJECT_ID('ShowQueryText', 'p') ; Retrieving the plans for compiled objects. SELECT refcounts , usecounts , size_in_bytes , cacheobjtype , objtype FROM sys.dm_exec_cached_plans WHERE objtype IN ( 'proc', 'prepared' ) ; Total number of cached plans. SELECT COUNT(*) FROM sys.dm_exec_cached_plans ; An overview of plan reuse. SELECT MAX(CASE WHEN usecounts BETWEEN 10 AND 100 THEN '10-100' WHEN usecounts BETWEEN 101 AND 1000 THEN '101-1000' WHEN usecounts BETWEEN 1001 AND 5000 THEN '1001-5000' WHEN usecounts BETWEEN 5001 AND 10000 THEN '5001-10000' ELSE CAST(usecounts AS VARCHAR(100)) END) AS usecounts , COUNT(*) AS countInstance FROM sys.dm_exec_cached_plans GROUP BY CASE WHEN usecounts BETWEEN 10 AND 100 THEN 50 WHEN usecounts BETWEEN 101 AND 1000 THEN 500 WHEN usecounts BETWEEN 1001 AND 5000 THEN 2500 WHEN usecounts BETWEEN 5001 AND 10000 THEN 7500 ELSE usecounts END ORDER BY CASE WHEN usecounts BETWEEN 10 AND 100 THEN 50 WHEN usecounts BETWEEN 101 AND 1000 THEN 500 WHEN usecounts BETWEEN 1001 AND 5000 THEN 2500 WHEN usecounts BETWEEN 5001 AND 10000 THEN 7500 ELSE usecounts END DESC ; Investigating the most used plans. SELECT TOP 2 WITH TIES decp.usecounts , decp.cacheobjtype , decp.objtype , deqp.query_plan , dest.text FROM sys.dm_exec_cached_plans decp CROSS APPLY sys.dm_exec_query_plan(decp.plan_handle) AS deqp CROSS APPLY sys.dm_exec_sql_text(decp.plan_handle) AS dest ORDER BY usecounts DESC ; Examining plan reuse for a single procedure SELECT usecounts , cacheobjtype , objtype , OBJECT_NAME(dest.objectid) FROM sys.dm_exec_cached_plans decp CROSS APPLY sys.dm_exec_sql_text(decp.plan_handle) AS dest WHERE dest.objectid = OBJECT_ID('<procedureName>') AND dest.dbid = DB_ID() ORDER BY usecounts DESC ; Examining single-use plans in the cache -- Find single-use, ad hoc queries that are bloating the plan cache SELECT TOP ( 100 ) [text] , cp.size_in_bytes FROM sys.dm_exec_cached_plans AS cp CROSS APPLY sys.dm_exec_sql_text(plan_handle) WHERE cp.cacheobjtype = 'Compiled Plan' AND cp.objtype = 'Adhoc' AND cp.usecounts = 1 ORDER BY cp.size_in_bytes DESC ; Examining plan attributes. SELECT CAST(depa.attribute AS VARCHAR(30)) AS attribute , CAST(depa.value AS VARCHAR(30)) AS value , depa.is_cache_key FROM ( SELECT TOP 1 * FROM sys.dm_exec_cached_plans ORDER BY usecounts DESC ) decp OUTER APPLY sys.dm_exec_plan_attributes(decp.plan_handle) depa WHERE is_cache_key = 1 ORDER BY usecounts DESC ; Finding the CPU-intensive queries. SELECT TOP 3 total_worker_time , execution_count , total_worker_time / execution_count AS [Avg CPU Time] , CASE WHEN deqs.statement_start_offset = 0 AND deqs.statement_end_offset = -1 THEN '-- see objectText column--' ELSE '-- query --' + CHAR(13) + CHAR(10) + SUBSTRING(execText.text, deqs.statement_start_offset / 2, ( ( CASE WHEN deqs.statement_end_offset = -1 THEN DATALENGTH(execText.text) ELSE deqs.statement_end_offset END ) - deqs.statement_start_offset ) / 2) END AS queryText FROM sys.dm_exec_query_stats deqs CROSS APPLY sys.dm_exec_sql_text(deqs.plan_handle) AS execText ORDER BY deqs.total_worker_time DESC ; Grouping by sql_handle to see query stats at the batch level. SELECT TOP 100 SUM(total_logical_reads) AS total_logical_reads , COUNT(*) AS num_queries , --number of individual queries in batch --not all usages need be equivalent, in the case of looping --or branching code MAX(execution_count) AS execution_count , MAX(execText.text) AS queryText FROM sys.dm_exec_query_stats deqs CROSS APPLY sys.dm_exec_sql_text(deqs.sql_handle) AS execText GROUP BY deqs.sql_handle HAVING AVG(total_logical_reads / execution_count) <> SUM(total_logical_reads) / SUM(execution_count) ORDER BY 1 DESC Investigating logical reads performed by cached stored procedures. -- Top Cached SPs By Total Logical Reads (SQL 2008 only). -- Logical reads relate to memory pressure SELECT TOP ( 25 ) p.name AS [SP Name] , deps.total_logical_reads AS [TotalLogicalReads] , deps.total_logical_reads / deps.execution_count AS [AvgLogicalReads] , deps.execution_count , ISNULL(deps.execution_count / DATEDIFF(Second, deps.cached_time, GETDATE()), 0) AS [Calls/Second] , deps.total_elapsed_time , deps.total_elapsed_time / deps.execution_count AS [avg_elapsed_time] , deps.cached_time FROM sys.procedures AS p INNER JOIN sys.dm_exec_procedure_stats AS deps ON p.[object_id] = deps.[object_id] WHERE deps.database_id = DB_ID() ORDER BY deps.total_logical_reads DESC ; Examine optimizer counters. SELECT counter , occurrence , value FROM sys.dm_exec_query_optimizer_info WHERE counter IN ( 'optimizations', 'elapsed time', 'final cost' ) ; Trivial changes to query text can affect plan reuse. SELECT COUNTER , OCCURRENCE , VALUE FROM SYS.DM_EXEC_QUERY_OPTIMIZER_INFO WHERE COUNTER IN ( 'optimizations', 'elapsed time', 'final cost' ) ; Locking due to single UPDATE statement against a user table in SQL Server SELECT [resource_type] , DB_NAME([resource_database_id]) AS [Database Name] , CASE WHEN DTL.resource_type IN ( 'DATABASE', 'FILE', 'METADATA' ) THEN DTL.resource_type WHEN DTL.resource_type = 'OBJECT' THEN OBJECT_NAME(DTL.resource_associated_entity_id, DTL.[resource_database_id]) WHEN DTL.resource_type IN ( 'KEY', 'PAGE', 'RID' ) THEN ( SELECT OBJECT_NAME([object_id]) FROM sys.partitions WHERE sys.partitions.hobt_id = DTL.resource_associated_entity_id ) ELSE 'Unidentified' END AS requested_object_name , [request_mode] , [resource_description] FROM sys.dm_tran_locks DTL WHERE DTL.[resource_type] <> 'DATABASE' ; Which sessions are causing blocking and what statement are they running? SELECT DTL.[request_session_id] AS [session_id] , DB_NAME(DTL.[resource_database_id]) AS [Database] , DTL.resource_type , CASE WHEN DTL.resource_type IN ( 'DATABASE', 'FILE', 'METADATA' ) THEN DTL.resource_type WHEN DTL.resource_type = 'OBJECT' THEN OBJECT_NAME(DTL.resource_associated_entity_id, DTL.[resource_database_id]) WHEN DTL.resource_type IN ( 'KEY', 'PAGE', 'RID' ) THEN ( SELECT OBJECT_NAME([object_id]) FROM sys.partitions WHERE sys.partitions.hobt_id = DTL.resource_associated_entity_id ) ELSE 'Unidentified' END AS [Parent Object] , DTL.request_mode AS [Lock Type] , DTL.request_status AS [Request Status] , DER.[blocking_session_id] , DES.[login_name] , CASE DTL.request_lifetime WHEN 0 THEN DEST_R.TEXT ELSE DEST_C.TEXT END AS [Statement] FROM sys.dm_tran_locks DTL LEFT JOIN sys.[dm_exec_requests] DER ON DTL.[request_session_id] = DER.[session_id] INNER JOIN sys.dm_exec_sessions DES ON DTL.request_session_id = DES.[session_id] INNER JOIN sys.dm_exec_connections DEC ON DTL.[request_session_id] = DEC.[most_recent_session_id] OUTER APPLY sys.dm_exec_sql_text(DEC.[most_recent_sql_handle]) AS DEST_C OUTER APPLY sys.dm_exec_sql_text(DER.sql_handle) AS DEST_R WHERE DTL.[resource_database_id] = DB_ID() AND DTL.[resource_type] NOT IN ( 'DATABASE', 'METADATA' ) ORDER BY DTL.[request_session_id] ; Investigating locking and blocking based on waiting tasks. SELECT DTL.[resource_type] AS [resource type] , CASE WHEN DTL.[resource_type] IN ( 'DATABASE', 'FILE', 'METADATA' ) THEN DTL.[resource_type] WHEN DTL.[resource_type] = 'OBJECT' THEN OBJECT_NAME(DTL.resource_associated_entity_id) WHEN DTL.[resource_type] IN ( 'KEY', 'PAGE', 'RID' ) THEN ( SELECT OBJECT_NAME([object_id]) FROM sys.partitions WHERE sys.partitions.[hobt_id] = DTL.[resource_associated_entity_id] ) ELSE 'Unidentified' END AS [Parent Object] , DTL.[request_mode] AS [Lock Type] , DTL.[request_status] AS [Request Status] , DOWT.[wait_duration_ms] AS [wait duration ms] , DOWT.[wait_type] AS [wait type] , DOWT.[session_id] AS [blocked session id] , DES_blocked.[login_name] AS [blocked_user] , SUBSTRING(dest_blocked.text, der.statement_start_offset / 2, ( CASE WHEN der.statement_end_offset = -1 THEN DATALENGTH(dest_blocked.text) ELSE der.statement_end_offset END - der.statement_start_offset ) / 2 AS [blocked_command] , DOWT.[blocking_session_id] AS [blocking session id] , DES_blocking.[login_name] AS [blocking user] , DEST_blocking.[text] AS [blocking command] , DOWT.resource_description AS [blocking resource detail] FROM sys.dm_tran_locks DTL INNER JOIN sys.dm_os_waiting_tasks DOWT ON DTL.lock_owner_address = DOWT.resource_address INNER JOIN sys.[dm_exec_requests] DER ON DOWT.[session_id] = DER.[session_id] INNER JOIN sys.dm_exec_sessions DES_blocked ON DOWT.[session_id] = DES_Blocked.[session_id] INNER JOIN sys.dm_exec_sessions DES_blocking ON DOWT.[blocking_session_id] = DES_Blocking.[session_id] INNER JOIN sys.dm_exec_connections DEC ON DTL.[request_session_id] = DEC.[most_recent_session_id] CROSS APPLY sys.dm_exec_sql_text(DEC.[most_recent_sql_handle]) AS DEST_Blocking CROSS APPLY sys.dm_exec_sql_text(DER.sql_handle) AS DEST_Blocked WHERE DTL.[resource_database_id] = DB_ID() Querying sys.dm_db_tran_active_transactions SELECT DTAT.transaction_id , DTAT.[name] , DTAT.transaction_begin_time , CASE DTAT.transaction_type WHEN 1 THEN 'Read/write' WHEN 2 THEN 'Read-only' WHEN 3 THEN 'System' WHEN 4 THEN 'Distributed' END AS transaction_type , CASE DTAT.transaction_state WHEN 0 THEN 'Not fully initialized' WHEN 1 THEN 'Initialized, not started' WHEN 2 THEN 'Active' WHEN 3 THEN 'Ended' -- only applies to read-only transactions WHEN 4 THEN 'Commit initiated'-- distributed transactions only WHEN 5 THEN 'Prepared, awaiting resolution' WHEN 6 THEN 'Committed' WHEN 7 THEN 'Rolling back' WHEN 8 THEN 'Rolled back' END AS transaction_state , CASE DTAT.dtc_state WHEN 1 THEN 'Active' WHEN 2 THEN 'Prepared' WHEN 3 THEN 'Committed' WHEN 4 THEN 'Aborted' WHEN 5 THEN 'Recovered' END AS dtc_state FROM sys.dm_tran_active_transactions DTAT INNER JOIN sys.dm_tran_session_transactions DTST ON DTAT.transaction_id = DTST.transaction_id WHERE [DTST].[is_user_transaction] = 1 ORDER BY DTAT.transaction_begin_time Eliminating worktables from the results returned by active_transactions. FROM sys.dm_tran_active_transactions DTAT WHERE DTAT.name <> 'worktable' ORDER BY DTAT.transaction_begin_time Decoding the integer values returned by database_transaction_state. CASE SDTDT.database_transaction_state WHEN 1 THEN 'Not initialized' WHEN 3 THEN 'initialized, but not producing log records' WHEN 4 THEN 'Producing log records' WHEN 5 THEN 'Prepared' WHEN 10 THEN 'Committed' WHEN 11 THEN 'Rolled back' WHEN 12 THEN 'Commit in process' Transaction log impact of active transactions. SELECT DTST.[session_id], DES.[login_name] AS [Login Name], DB_NAME (DTDT.database_id) AS [Database], DTDT.[database_transaction_begin_time] AS [Begin Time], -- DATEDIFF(ms,DTDT.[database_transaction_begin_time], GETDATE()) AS [Duration ms], CASE DTAT.transaction_type WHEN 1 THEN 'Read/write' WHEN 2 THEN 'Read-only' WHEN 3 THEN 'System' WHEN 4 THEN 'Distributed' END AS [Transaction Type], CASE DTAT.transaction_state WHEN 0 THEN 'Not fully initialized' WHEN 1 THEN 'Initialized, not started' WHEN 2 THEN 'Active' WHEN 3 THEN 'Ended' WHEN 4 THEN 'Commit initiated' WHEN 5 THEN 'Prepared, awaiting resolution' WHEN 6 THEN 'Committed' WHEN 7 THEN 'Rolling back' WHEN 8 THEN 'Rolled back' END AS [Transaction State], DTDT.[database_transaction_log_record_count] AS [Log Records], DTDT.[database_transaction_log_bytes_used] AS [Log Bytes Used], DTDT.[database_transaction_log_bytes_reserved] AS [Log Bytes RSVPd], DEST.[text] AS [Last Transaction Text], DEQP.[query_plan] AS [Last Query Plan] FROM sys.dm_tran_database_transactions DTDT INNER JOIN sys.dm_tran_session_transactions DTST ON DTST.[transaction_id] = DTDT.[transaction_id] INNER JOIN sys.[dm_tran_active_transactions] DTAT ON DTST.[transaction_id] = DTAT.[transaction_id] INNER JOIN sys.[dm_exec_sessions] DES ON DES.[session_id] = DTST.[session_id] INNER JOIN sys.dm_exec_connections DEC ON DEC.[session_id] = DTST.[session_id] LEFT JOIN sys.dm_exec_requests DER ON DER.[session_id] = DTST.[session_id] CROSS APPLY sys.dm_exec_sql_text (DEC.[most_recent_sql_handle]) AS DEST OUTER APPLY sys.dm_exec_query_plan (DER.[plan_handle]) AS DEQP ORDER BY DTDT.[database_transaction_log_bytes_used] DESC; -- ORDER BY [Duration ms] DESC; Which databases are using snapshot isolation SELECT SD.[name] , SD.snapshot_isolation_state_desc , SD.is_read_committed_snapshot_on FROM sys.databases SD WHERE SD.snapshot_isolation_state_desc = 'ON' Interrogating the active_snapshot_database_transactions DMV SELECT DTASDT.transaction_id , DTASDT.session_id , DTASDT.transaction_sequence_num , DTASDT.first_snapshot_sequence_num , DTASDT.commit_sequence_num , DTASDT.is_snapshot , DTASDT.elapsed_time_seconds , DEST.text AS [command text] FROM sys.dm_tran_active_snapshot_database_transactions DTASDT INNER JOIN sys.dm_exec_connections DEC ON DTASDT.session_id = DEC.most_recent_session_id INNER JOIN sys.dm_tran_database_transactions DTDT ON DTASDT.transaction_id = DTDT.transaction_id CROSS APPLY sys.dm_exec_sql_text(DEC.most_recent_sql_handle) AS DEST WHERE DTDT.database_id = DB_ID() Correlating the activity of the various transactions that are using the version store SELECT DTTS.[transaction_sequence_num] , trx_current.[session_id] AS current_session_id , DES_current.[login_name] AS [current session login] , DEST_current.text AS [current session command] , DTTS.[snapshot_sequence_num] , trx_existing.[session_id] AS existing_session_id , DES_existing.[login_name] AS [existing session login] , DEST_existing.text AS [existing session command] FROM sys.dm_tran_transactions_snapshot DTTS INNER JOIN sys.[dm_tran_active_snapshot_database_transactions] trx_current ON DTTS.[transaction_sequence_num] = trx_current.[transaction_sequence_num] INNER JOIN sys.[dm_exec_connections] DEC_current ON trx_current.[session_id] = DEC_current.[most_recent_session_id] INNER JOIN sys.[dm_exec_sessions] DES_current ON DEC_current.[most_recent_session_id] = DES_current.[session_id] INNER JOIN sys.[dm_tran_active_snapshot_database_transactions] trx_existing ON DTTS.[snapshot_sequence_num] = trx_existing.[transaction_sequence_num] INNER JOIN sys.[dm_exec_connections] DEC_existing ON trx_existing.[session_id] = DEC_existing.[most_recent_session_id] INNER JOIN sys.[dm_exec_sessions] DES_existing ON DEC_existing.[most_recent_session_id] = DES_existing.[session_id] CROSS APPLY sys.[dm_exec_sql_text] (DEC_current.[most_recent_sql_handle]) DEST_current CROSS APPLY sys.[dm_exec_sql_text] (DEC_existing.[most_recent_sql_handle]) DEST_existing ORDER BY DTTS.[transaction_sequence_num] , DTTS.[snapshot_sequence_num] ; Returning raw data from sys.dm_tran_version_store. SELECT DB_NAME(DTVS.database_id) AS [Database Name] , DTVS.[transaction_sequence_num] , DTVS.[version_sequence_num] , CASE DTVS.[status] WHEN 0 THEN '1' WHEN 1 THEN '2' END AS [pages] , DTVS.[record_length_first_part_in_bytes] + DTVS.[record_length_second_part_in_bytes] AS [record length (bytes)] FROM sys.dm_tran_version_store DTVS ORDER BY DB_NAME(DTVS.database_id) , DTVS.transaction_sequence_num , DTVS.version_sequence_num Storage requirements for the version store SELECT DB_NAME(DTVS.[database_id]) , SUM(DTVS.[record_length_first_part_in_bytes] + DTVS.[record_length_second_part_in_bytes]) AS [total store bytes consumed] FROM sys.dm_tran_version_store DTVS GROUP BY DB_NAME(DTVS.[database_id]) ; Finding the highest-consuming version store record within tempdb. WITH version_store ( [rowset_id], [bytes consumed] ) AS ( SELECT TOP 1 [rowset_id] , SUM([record_length_first_part_in_bytes] + [record_length_second_part_in_bytes]) AS [bytes consumed] FROM sys.dm_tran_version_store GROUP BY [rowset_id] ORDER BY SUM([record_length_first_part_in_bytes] + [record_length_second_part_in_bytes]) ) SELECT VS.[rowset_id] , VS.[bytes consumed] , DB_NAME(DTVS.[database_id]) AS [database name] , DTASDT.[session_id] AS session_id , DES.[login_name] AS [session login] , DEST.text AS [session command] FROM version_store VS INNER JOIN sys.[dm_tran_version_store] DTVS ON VS.rowset_id = DTVS.[rowset_id] INNER JOIN sys.[dm_tran_active_snapshot_database_transactions] DTASDT ON DTVS.[transaction_sequence_num] = DTASDT.[transaction_sequence_num] INNER JOIN sys.dm_exec_connections DEC ON DTASDT.[session_id] = DEC.[most_recent_session_id] INNER JOIN sys.[dm_exec_sessions] DES ON DEC.[most_recent_session_id] = DES.[session_id] CROSS APPLY sys.[dm_exec_sql_text](DEC.[most_recent_sql_handle]) DEST ; Returning raw data from sys.dm_tran_top_version_generators. SELECT DB_NAME(DTTVG.[database_id]) , DTTVG.[rowset_id] , DTTVG.[aggregated_record_length_in_bytes] FROM sys.[dm_tran_top_version_generators] DTTVG ORDER BY DTTVG.[aggregated_record_length_in_bytes] DESC ; Querying index use in the AdventureWorks database SELECT DB_NAME(ddius.[database_id]) AS database_name , OBJECT_NAME(ddius.[object_id], DB_ID('AdventureWorks')) AS [object_name] , asi.[name] AS index_name , ddius.user_seeks + ddius.user_scans + ddius.user_lookups AS user_reads FROM sys.dm_db_index_usage_stats ddius INNER JOIN AdventureWorks.sys.indexes asi ON ddius.[object_id] = asi.[object_id] AND ddius.index_id = asi.index_id ; The combination of object_id and index_id cannot guarantee uniqueness at the instance level. SELECT DB_NAME(ddius.[database_id]) AS [database_name] , ddius.[database_id] , ddius.[object_id] , ddius.[index_id] FROM sys.[dm_db_index_usage_stats] ddius INNER JOIN AdventureWorks.sys.[indexes] asi ON ddius.[object_id] = asi.[object_id] AND ddius.[index_id] = asi.[index_id] Usage stats for indexes that have been used to resolve a query. SELECT OBJECT_NAME(ddius.[object_id], ddius.database_id) AS [object_name] , ddius.index_id , ddius.user_seeks , ddius.user_scans , ddius.user_lookups , ddius.user_seeks + ddius.user_scans + ddius.user_lookups AS user_reads , ddius.user_updates AS user_writes , ddius.last_user_scan , ddius.last_user_update FROM sys.dm_db_index_usage_stats ddius WHERE ddius.database_id > 4 -- filter out system tables AND OBJECTPROPERTY(ddius.object_id, 'IsUserTable') = 1 AND ddius.index_id > 0 -- filter out heaps ORDER BY ddius.user_scans DESC Finding unused indexes. -- List unused indexes SELECT OBJECT_NAME(i.[object_id]) AS [Table Name] , i.name FROM sys.indexes AS i INNER JOIN sys.objects AS o ON i.[object_id] = o.[object_id] WHERE i.index_id NOT IN ( SELECT ddius.index_id FROM sys.dm_db_index_usage_stats AS ddius WHERE ddius.[object_id] = i.[object_id] AND i.index_id = ddius.index_id AND database_id = DB_ID() ) AND o.[type] = 'U' ORDER BY OBJECT_NAME(i.[object_id]) ASC ; Querying sys.dm_db_index_usage_stats for indexes that are being maintained but not used. SELECT '[' + DB_NAME() + '].[' + su.[name] + '].[' + o.[name] + ']' AS [statement] , i.[name] AS [index_name] , ddius.[user_seeks] + ddius.[user_scans] + ddius.[user_lookups] AS [user_reads] , ddius.[user_updates] AS [user_writes] , SUM(SP.rows) AS [total_rows] FROM sys.dm_db_index_usage_stats ddius INNER JOIN sys.indexes i ON ddius.[object_id] = i.[object_id] AND i.[index_id] = ddius.[index_id] INNER JOIN sys.partitions SP ON ddius.[object_id] = SP.[object_id] AND SP.[index_id] = ddius.[index_id] INNER JOIN sys.objects o ON ddius.[object_id] = o.[object_id] INNER JOIN sys.sysusers su ON o.[schema_id] = su.[UID] WHERE ddius.[database_id] = DB_ID() -- current database only AND OBJECTPROPERTY(ddius.[object_id], 'IsUserTable') = 1 AND ddius.[index_id] > 0 GROUP BY su.[name] , o.[name] , i.[name] , ddius.[user_seeks] + ddius.[user_scans] + ddius.[user_lookups] , ddius.[user_updates] HAVING ddius.[user_seeks] + ddius.[user_scans] + ddius.[user_lookups] = 0 ORDER BY ddius.[user_updates] DESC , su.[name] , o.[name] , i.[name ] Genarage drop index command in SELECT 'DROP INDEX [' + i.[name] + '] ON [' + su.[name] + '].[' + o.[name] + '] WITH ( ONLINE = OFF )' AS [drop_command] How old are the index usage stats? SELECT DATEDIFF(DAY, sd.crdate, GETDATE()) AS days_history FROM sys.sysdatabases sd WHERE sd.[name] = 'tempdb' ; Finding rarely-used indexes. -- Potentially inefficient non-clustered indexes (writes > reads) SELECT OBJECT_NAME(ddius.[object_id]) AS [Table Name] , i.name AS [Index Name] , i.index_id , user_updates AS [Total Writes] , user_seeks + user_scans + user_lookups AS [Total Reads] , user_updates - ( user_seeks + user_scans + user_lookups ) AS [Difference] FROM sys.dm_db_index_usage_stats AS ddius WITH ( NOLOCK ) INNER JOIN sys.indexes AS i WITH ( NOLOCK ) ON ddius.[object_id] = i.[object_id] AND i.index_id = ddius.index_id WHERE OBJECTPROPERTY(ddius.[object_id], 'IsUserTable') = 1 AND ddius.database_id = DB_ID() AND user_updates > ( user_seeks + user_scans + user_lookups ) AND i.index_id > 1 ORDER BY [Difference] DESC , [Total Writes] DESC , [Total Reads] ASC ; Detailed write information for unused indexes. SELECT '[' + DB_NAME() + '].[' + su.[name] + '].[' + o.[name] + ']' AS [statement] , i.[name] AS [index_name] , ddius.[user_seeks] + ddius.[user_scans] + ddius.[user_lookups] AS [user_reads] , ddius.[user_updates] AS [user_writes] , ddios.[leaf_insert_count] , ddios.[leaf_delete_count] , ddios.[leaf_update_count] , ddios.[nonleaf_insert_count] , ddios.[nonleaf_delete_count] , ddios.[nonleaf_update_count] FROM sys.dm_db_index_usage_stats ddius INNER JOIN sys.indexes i ON ddius.[object_id] = i.[object_id] AND i.[index_id] = ddius.[index_id] INNER JOIN sys.partitions SP ON ddius.[object_id] = SP.[object_id] AND SP.[index_id] = ddius.[index_id] INNER JOIN sys.objects o ON ddius.[object_id] = o.[object_id] INNER JOIN sys.sysusers su ON o.[schema_id] = su.[UID] INNER JOIN sys.[dm_db_index_operational_stats](DB_ID(), NULL, NULL, NULL) AS ddios ON ddius.[index_id] = ddios.[index_id] AND ddius.[object_id] = ddios.[object_id] AND SP.[partition_number] = ddios.[partition_number] AND ddius.[database_id] = ddios.[database_id] WHERE OBJECTPROPERTY(ddius.[object_id], 'IsUserTable') = 1 AND ddius.[index_id] > 0 AND ddius.[user_seeks] + ddius.[user_scans] + ddius.[user_lookups] = 0 ORDER BY ddius.[user_updates] DESC , su.[name] , o.[name] , i.[name ] Retrieving locking and blocking details for each index. SELECT '[' + DB_NAME(ddios.[database_id]) + '].[' + su.[name] + '].[' + o.[name] + ']' AS [statement] , i.[name] AS 'index_name' , ddios.[partition_number] , ddios.[row_lock_count] , ddios.[row_lock_wait_count] , CAST (100.0 * ddios.[row_lock_wait_count] / ( ddios.[row_lock_count] ) AS DECIMAL(5, 2)) AS [%_times_blocked] , ddios.[row_lock_wait_in_ms] , CAST (1.0 * ddios.[row_lock_wait_in_ms] / ddios.[row_lock_wait_count] AS DECIMAL(15, 2)) AS [avg_row_lock_wait_in_ms] FROM sys.dm_db_index_operational_stats(DB_ID(), NULL, NULL, NULL) ddios INNER JOIN sys.indexes i ON ddios.[object_id] = i.[object_id] AND i.[index_id] = ddios.[index_id] INNER JOIN sys.objects o ON ddios.[object_id] = o.[object_id] INNER JOIN sys.sysusers su ON o.[schema_id] = su.[UID] WHERE ddios.row_lock_wait_count > 0 AND OBJECTPROPERTY(ddios.[object_id], 'IsUserTable') = 1 AND i.[index_id] > 0 ORDER BY ddios.[row_lock_wait_count] DESC , su.[name] , o.[name] , i.[name ] Investigating latch waits. SELECT '[' + DB_NAME() + '].[' + OBJECT_SCHEMA_NAME(ddios.[object_id]) + '].[' + OBJECT_NAME(ddios.[object_id]) + ']' AS [object_name] , i.[name] AS index_name , ddios.page_io_latch_wait_count , ddios.page_io_latch_wait_in_ms , ( ddios.page_io_latch_wait_in_ms / ddios.page_io_latch_wait_count ) AS avg_page_io_latch_wait_in_ms FROM sys.dm_db_index_operational_stats(DB_ID(), NULL, NULL, NULL) ddios INNER JOIN sys.indexes i ON ddios.[object_id] = i.[object_id] AND i.index_id = ddios.index_id WHERE ddios.page_io_latch_wait_count > 0 AND OBJECTPROPERTY(i.object_id, 'IsUserTable') = 1 ORDER BY ddios.page_io_latch_wait_count DESC , avg_page_io_latch_wait_in_ms DESC Investigating lock escalation. SELECT OBJECT_NAME(ddios.[object_id], ddios.database_id) AS [object_name] , i.name AS index_name , ddios.index_id , ddios.partition_number , ddios.index_lock_promotion_attempt_count , ddios.index_lock_promotion_count , ( ddios.index_lock_promotion_attempt_count / ddios.index_lock_promotion_count ) AS percent_success FROM sys.dm_db_index_operational_stats(DB_ID(), NULL, NULL, NULL) ddios INNER JOIN sys.indexes i ON ddios.object_id = i.object_id AND ddios.index_id = i.index_id WHERE ddios.index_lock_promotion_count > 0 ORDER BY index_lock_promotion_count DESC ; Indexes associated with lock contention. SELECT OBJECT_NAME(ddios.object_id, ddios.database_id) AS object_name , i.name AS index_name , ddios.index_id , ddios.partition_number , ddios.page_lock_wait_count , ddios.page_lock_wait_in_ms , CASE WHEN DDMID.database_id IS NULL THEN 'N' ELSE 'Y' END AS missing_index_identified FROM sys.dm_db_index_operational_stats(DB_ID(), NULL, NULL, NULL) ddios INNER JOIN sys.indexes i ON ddios.object_id = i.object_id AND ddios.index_id = i.index_id LEFT OUTER JOIN ( SELECT DISTINCT database_id , object_id FROM sys.dm_db_missing_index_details ) AS DDMID ON DDMID.database_id = ddios.database_id AND DDMID.object_id = ddios.object_id WHERE ddios.page_lock_wait_in_ms > 0 ORDER BY ddios.page_lock_wait_count DESC ; Finding beneficial missing indexes. SELECT user_seeks * avg_total_user_cost * ( avg_user_impact * 0.01 ) AS [index_advantage] , dbmigs.last_user_seek , dbmid.[statement] AS [Database.Schema.Table] , dbmid.equality_columns , dbmid.inequality_columns , dbmid.included_columns , dbmigs.unique_compiles , dbmigs.user_seeks , dbmigs.avg_total_user_cost , dbmigs.avg_user_impact FROM sys.dm_db_missing_index_group_stats AS dbmigs WITH ( NOLOCK ) INNER JOIN sys.dm_db_missing_index_groups AS dbmig WITH ( NOLOCK ) ON dbmigs.group_handle = dbmig.index_group_handle INNER JOIN sys.dm_db_missing_index_details AS dbmid WITH ( NOLOCK ) ON dbmig.index_handle = dbmid.index_handle WHERE dbmid.[database_id] = DB_ID() ORDER BY index_advantage DESC ; Investigating fragmented indexes. SELECT '[' + DB_NAME() + '].[' + OBJECT_SCHEMA_NAME(ddips.[object_id], DB_ID()) + '].[' + OBJECT_NAME(ddips.[object_id], DB_ID()) + ']' AS [statement] , i.[name] AS [index_name] , ddips.[index_type_desc] , ddips.[partition_number] , ddips.[alloc_unit_type_desc] , ddips.[index_depth] , ddips.[index_level] , CAST(ddips.[avg_fragmentation_in_percent] AS SMALLINT) AS [avg_frag_%] , CAST(ddips.[avg_fragment_size_in_pages] AS SMALLINT) AS [avg_frag_size_in_pages] , ddips.[fragment_count] , ddips.[page_count] FROM sys.dm_db_index_physical_stats(DB_ID(), NULL, NULL, NULL, 'limited') ddips INNER JOIN sys.[indexes] i ON ddips.[object_id] = i.[object_id] AND ddips.[index_id] = i.[index_id] WHERE ddips.[avg_fragmentation_in_percent] > 15 AND ddips.[page_count] > 500 ORDER BY ddips.[avg_fragmentation_in_percent] , OBJECT_NAME(ddips.[object_id], DB_ID()) , i.[name ] Number of rows in clustered tables and heaps. SELECT object_schema_name(ddps.object_id) + '.' + OBJECT_NAME(ddps.object_id) AS name , SUM(ddps.row_count) AS row_count FROM sys.dm_db_partition_stats AS ddps JOIN sys.indexes ON indexes.object_id = ddps.object_id AND indexes.index_id = ddps.index_id WHERE indexes.type_desc IN ( 'CLUSTERED', 'HEAP' ) and objectproperty(ddps.object_id,'IsMSShipped') = 0 GROUP BY ddps.object_id Creating a three-partition salesOrder table. CREATE PARTITION FUNCTION PFdateRange (SMALLDATETIME) AS RANGE LEFT FOR VALUES ('20020101','20030101') ; GO CREATE PARTITION SCHEME PSdateRange AS PARTITION PFdateRange ALL TO ( [PRIMARY] ) GO CREATE TABLE salesOrder ( salesOrderId INT , customerId INT , orderAmount DECIMAL(10, 2) , orderDate SMALLDATETIME , CONSTRAINT PKsalesOrder PRIMARY KEY NONCLUSTERED ( salesOrderId ) ON [Primary] , CONSTRAINT AKsalesOrder UNIQUE CLUSTERED ( salesOrderId, orderDate ) ) --the ON clause causes this clustered table to be partitioned by orderDate --using the partition function/scheme ON PSdateRange(orderDate) GO --Generate some random data INSERT INTO salesOrder SELECT SalesOrderId , CustomerId , TotalDue , OrderDate FROM AdventureWorks.Sales.SalesOrderHeader Number of rows in each object, per partition. SELECT indexes.name , indexes.type_desc , dps.row_count AS row_count , partition_id FROM sys.dm_db_partition_stats AS dps JOIN sys.indexes ON indexes.object_id = dps.object_id AND indexes.index_id = dps.index_id WHERE OBJECT_ID('salesOrder') = dps.object_id Physical characteristics of each partition SELECT OBJECT_NAME(indexes.object_id) AS Object_Name , ddps.index_id AS Index_ID , ddps.partition_number , ddps.row_count , ddps.used_page_count , ddps.in_row_reserved_page_count , ddps.lob_reserved_page_count , CASE pf.boundary_value_on_right WHEN 1 THEN 'less than' ELSE 'less than or equal to' END AS comparison , value FROM sys.dm_db_partition_stats ddps JOIN sys.indexes ON ddps.object_id = indexes.object_id AND ddps.index_id = indexes.index_id JOIN sys.partition_schemes ps ON ps.data_space_id = indexes.data_space_id JOIN sys.partition_functions pf ON pf.function_id = ps.function_id LEFT OUTER JOIN sys.partition_range_values prv ON pf.function_id = prv.function_id AND ddps.partition_number = prv.boundary_id WHERE OBJECT_NAME(ddps.object_id) = 'salesOrder ' AND ddps.index_id IN ( 0, 1 ) --CLUSTERED table or HEAP Fragmentation statistics for the testClusteredIdentity clustered table SELECT avg_fragmentation_in_percent AS avgFragPct , fragment_count AS fragCount , avg_fragment_size_in_pages AS avgFragSize FROM sys.dm_db_index_physical_stats(DB_ID(), NULL, NULL, NULL, 'DETAILED') WHERE index_type_desc = 'CLUSTERED INDEX' AND index_level = 0 -- the other levels are the index pages AND OBJECT_NAME(object_id) = 'testClusteredIdentity' Fragmentation statistics for testHeap. SELECT avg_fragmentation_in_percent AS avgFragPct , fragment_count AS fragCount , avg_fragment_size_in_pages AS avgFragSize , forwarded_record_count AS forwardPointers FROM sys.dm_db_index_physical_stats(DB_ID(), NULL, NULL, NULL, 'DETAILED') WHERE index_type_desc = 'HEAP' AND index_level = 0 -- the other levels are the index pages AND OBJECT_NAME(object_id) = 'testHeap' Capturing baseline disk I/O statistics from sys.dm_io_virtual_file_stats in a temporary table. SELECT DB_NAME(mf.database_id) AS databaseName , mf.physical_name , divfs.num_of_reads , divfs.num_of_bytes_read , divfs.io_stall_read_ms , divfs.num_of_writes , divfs.num_of_bytes_written , divfs.io_stall_write_ms , divfs.io_stall , size_on_disk_bytes , GETDATE() AS baselineDate INTO #baseline FROM sys.dm_io_virtual_file_stats(NULL, NULL) AS divfs JOIN sys.master_files AS mf ON mf.database_id = divfs.database_id AND mf.file_id = divfs.file_id Querying the #baseline temporary table. SELECT physical_name , num_of_reads , num_of_bytes_read , io_stall_read_ms FROM #baseline WHERE databaseName = 'DatabaseName' Capturing 10 seconds of disk I/O statistics, since the baseline measurement. WITH currentLine AS ( SELECT DB_NAME(mf.database_id) AS databaseName , mf.physical_name , num_of_reads , num_of_bytes_read , io_stall_read_ms , num_of_writes , num_of_bytes_written , io_stall_write_ms , io_stall , size_on_disk_bytes , GETDATE() AS currentlineDate FROM sys.dm_io_virtual_file_stats(NULL, NULL) AS divfs JOIN sys.master_files AS mf ON mf.database_id = divfs.database_id AND mf.file_id = divfs.file_id ) SELECT currentLine.databaseName , LEFT(currentLine.physical_name, 1) AS drive , currentLine.physical_name , DATEDIFF(millisecond,baseLineDate,currentLineDate) AS elapsed_ms, currentLine.io_stall - #baseline.io_stall AS io_stall_ms , currentLine.io_stall_read_ms - #baseline.io_stall_read_ms AS io_stall_read_ms , currentLine.io_stall_write_ms - #baseline.io_stall_write_ms AS io_stall_write_ms , currentLine.num_of_reads - #baseline.num_of_reads AS num_of_reads , currentLine.num_of_bytes_read - #baseline.num_of_bytes_read AS num_of_bytes_read , currentLine.num_of_writes - #baseline.num_of_writes AS num_of_writes , currentLine.num_of_bytes_written - #baseline.num_of_bytes_written AS num_of_bytes_written FROM currentLine INNER JOIN #baseline ON #baseLine.databaseName = currentLine.databaseName AND #baseLine.physical_name = currentLine.physical_name WHERE #baseline.databaseName = 'DatabaseName' Returning pending I/O requests. SELECT mf.physical_name , dipir.io_pending , dipir.io_pending_ms_ticks FROM sys.dm_io_pending_io_requests AS dipir JOIN sys.dm_io_virtual_file_stats(NULL, NULL) AS divfs ON dipir.io_handle = divfs.file_handle JOIN sys.master_files AS mf ON divfs.database_id = mf.database_id AND divfs.file_id = mf.file_id ORDER BY dipir.io_pending , --Show I/O completed by the OS first dipir.io_pending_ms_ticks DESC The read:write ratio, by database, for amount of data transferred. --uses a LIKE comparison to only include desired databases, rather than --using the database_id parameter of sys.dm_io_virtual_file_stats --if you have a rather large number of databases, this may not be the --optimal way to execute the query, but this gives you flexibility --to look at multiple databases simultaneously. DECLARE @databaseName SYSNAME SET @databaseName = '%' --'%' gives all databases SELECT CAST(SUM(num_of_bytes_read) AS DECIMAL) / ( CAST(SUM(num_of_bytes_written) AS DECIMAL) + CAST(SUM(num_of_bytes_read) AS DECIMAL) ) AS RatioOfReads , CAST(SUM(num_of_bytes_written) AS DECIMAL) / ( CAST(SUM(num_of_bytes_written) AS DECIMAL) + CAST(SUM(num_of_bytes_read) AS DECIMAL) ) AS RatioOfWrites , SUM(num_of_bytes_read) AS TotalBytesRead , SUM(num_of_bytes_written) AS TotalBytesWritten FROM sys.dm_io_virtual_file_stats(NULL, NULL) AS divfs WHERE DB_NAME(database_id) LIKE @databaseName The read:write ratio, by drive, for amount of data transferred. DECLARE @databaseName SYSNAME SET @databaseName = '%' --'%' gives all databases SELECT LEFT(physical_name, 1) AS drive , CAST(SUM(num_of_bytes_read) AS DECIMAL) / ( CAST(SUM(num_of_bytes_written) AS DECIMAL) + CAST(SUM(num_of_bytes_read) AS DECIMAL) ) AS RatioOfReads , CAST(SUM(num_of_bytes_written) AS DECIMAL) / ( CAST(SUM(num_of_bytes_written) AS DECIMAL) + CAST(SUM(num_of_bytes_read) AS DECIMAL) ) AS RatioOfWrites , SUM(num_of_bytes_read) AS TotalBytesRead , SUM(num_of_bytes_written) AS TotalBytesWritten FROM sys.dm_io_virtual_file_stats(NULL, NULL) AS divfs JOIN sys.master_files AS mf ON mf.database_id = divfs.database_id AND mf.file_id = divfs.file_id WHERE DB_NAME(divfs.database_id) LIKE @databaseName GROUP BY LEFT(mf.physical_name, 1) The read:write ratio, by database, for number of read/write operations. DECLARE @databaseName SYSNAME SET @databaseName = 'BusyDatabase' --obviously not the real name --'%' gives all databases SELECT CAST(SUM(num_of_reads) AS DECIMAL) / ( CAST(SUM(num_of_writes) AS DECIMAL) + CAST(SUM(num_of_reads) AS DECIMAL) ) AS RatioOfReads , CAST(SUM(num_of_writes) AS DECIMAL) / ( CAST(SUM(num_of_reads) AS DECIMAL) + CAST(SUM(num_of_writes) AS DECIMAL) ) AS RatioOfWrites , SUM(num_of_reads) AS TotalReadOperations , SUM(num_of_writes) AS TotalWriteOperations FROM sys.dm_io_virtual_file_stats(NULL, NULL) AS divfs WHERE DB_NAME(database_id) LIKE @databaseName Read:write ratio for all objects in a given database. DECLARE @databaseName SYSNAME SET @databaseName = 'BusyDatabase' --obviously not the real name --'%' gives all databases SELECT CASE WHEN ( SUM(user_updates + user_seeks + user_scans + user_lookups) = 0 ) THEN NULL ELSE ( CAST(SUM(user_seeks + user_scans + user_lookups) AS DECIMAL) / CAST(SUM(user_updates + user_seeks + user_scans + user_lookups) AS DECIMAL) ) END AS RatioOfReads , CASE WHEN ( SUM(user_updates + user_seeks + user_scans + user_lookups) = 0 ) THEN NULL ELSE ( CAST(SUM(user_updates) AS DECIMAL) / CAST(SUM(user_updates + user_seeks + user_scans + user_lookups) AS DECIMAL) ) END AS RatioOfWrites , SUM(user_updates + user_seeks + user_scans + user_lookups) AS TotalReadOperations , SUM(user_updates) AS TotalWriteOperations FROM sys.dm_db_index_usage_stats AS ddius WHERE DB_NAME(database_id) LIKE @databaseName Read:write ratio per object. --only works in the context of the database due to sys.indexes usage USE BusyDatabase --obviously not the real name SELECT OBJECT_NAME(ddius.object_id) AS object_name , CASE WHEN ( SUM(user_updates + user_seeks + user_scans + user_lookups) = 0 ) THEN NULL ELSE ( CAST(SUM(user_seeks + user_scans + user_lookups) AS DECIMAL) / CAST(SUM(user_updates + user_seeks + user_scans + user_lookups) AS DECIMAL) ) END AS RatioOfReads , CASE WHEN ( SUM(user_updates + user_seeks + user_scans + user_lookups) = 0 ) THEN NULL ELSE ( CAST(SUM(user_updates) AS DECIMAL) / CAST(SUM(user_updates + user_seeks + user_scans + user_lookups) AS DECIMAL) ) END AS RatioOfWrites , SUM(user_updates + user_seeks + user_scans + user_lookups) AS TotalReadOperations , SUM(user_updates) AS TotalWriteOperations FROM sys.dm_db_index_usage_stats AS ddius JOIN sys.indexes AS i ON ddius.object_id = i.object_id AND ddius.index_id = i.index_id WHERE i.type_desc IN ( 'CLUSTERED', 'HEAP' ) --only works in Current db GROUP BY ddius.object_id ORDER BY OBJECT_NAME(ddius.object_id) An overview of tempdb utilization. SELECT mf.physical_name , mf.size AS entire_file_page_count , dfsu.version_store_reserved_page_count , dfsu.unallocated_extent_page_count , dfsu.user_object_reserved_page_count , dfsu.internal_object_reserved_page_count , dfsu.mixed_extent_page_count FROM sys.dm_db_file_space_usage dfsu JOIN sys.master_files AS mf ON mf.database_id = dfsu.database_id AND mf.file_id = dfsu.file_id tempdb file size and version store usage. SELECT SUM(mf.size) AS entire_page_count , SUM(dfsu.version_store_reserved_page_count) AS version_store_reserved_page_ count FROM sys.dm_db_file_space_usage dfsu JOIN sys.master_files AS mf ON mf.database_id = dfsu.database_id AND mf.file_id = dfsu.file_id Resetting the wait statistics. DBCC SQLPERF ('sys.dm_os_wait_stats', CLEAR); The most common waits. SELECT TOP 3 wait_type , waiting_tasks_count , wait_time_ms / 1000.0 AS wait_time_sec , CASE WHEN waiting_tasks_count = 0 THEN NULL ELSE wait_time_ms / 1000.0 / waiting_tasks_count END AS avg_wait_time_sec , max_wait_time_ms / 1000.0 AS max_wait_time_sec , ( wait_time_ms - signal_wait_time_ms ) / 1000.0 AS resource_wait_time_sec FROM sys.dm_os_wait_stats WHERE wait_type NOT IN --tasks that are actually good or expected --to be waited on ( 'CLR_SEMAPHORE', 'LAZYWRITER_SLEEP', 'RESOURCE_QUEUE', 'SLEEP_TASK', 'SLEEP_SYSTEMTASK', 'WAITFOR' ) ORDER BY waiting_tasks_count DESC Report on top resource waits. -- Isolate top waits for server instance since last restart -- or statistics clear WITH Waits AS ( SELECT wait_type , wait_time_ms / 1000. AS wait_time_sec , 100. * wait_time_ms / SUM(wait_time_ms) OVER ( ) AS pct , ROW_NUMBER() OVER ( ORDER BY wait_time_ms DESC ) AS rn FROM sys.dm_os_wait_stats WHERE wait_type NOT IN ( 'CLR_SEMAPHORE', 'LAZYWRITER_SLEEP', 'RESOURCE_QUEUE', 'SLEEP_TASK', 'SLEEP_SYSTEMTASK', 'SQLTRACE_BUFFER_FLUSH', 'WAITFOR', 'LOGMGR_QUEUE', 'CHECKPOINT_QUEUE' ) ) SELECT wait_type , CAST(wait_time_sec AS DECIMAL(12, 2)) AS wait_time_sec , CAST(pct AS DECIMAL(12, 2)) AS wait_time_percentage FROM Waits WHERE pct > 1 ORDER BY wait_time_sec DESC Seeking out locking waits. SELECT wait_type , waiting_tasks_count , wait_time_ms , max_wait_time_ms FROM sys.dm_os_wait_stats WHERE wait_type LIKE 'LCK%' AND Waiting_tasks_count > 0 ORDER BY waiting_tasks_count DESC Is there any CPU pressure? -- Total waits are wait_time_ms (high signal waits indicates CPU pressure) SELECT CAST(100.0 * SUM(signal_wait_time_ms) / SUM(wait_time_ms) AS NUMERIC(20,2)) AS [%signal (cpu) waits] , CAST(100.0 * SUM(wait_time_ms - signal_wait_time_ms) / SUM(wait_time_ms) AS NUMERIC(20, 2)) AS [%resource waits] FROM sys.dm_os_wait_stats ; Returning a list of PerfMon counter types. SELECT DISTINCT cntr_type FROM sys.dm_os_performance_counters ORDER BY cntr_type Returning the values of directly usable PerfMon counters. DECLARE @PERF_COUNTER_LARGE_RAWCOUNT INT SELECT @PERF_COUNTER_LARGE_RAWCOUNT = 65792 SELECT object_name , counter_name , instance_name , cntr_value FROM sys.dm_os_performance_counters WHERE cntr_type = @PERF_COUNTER_LARGE_RAWCOUNT ORDER BY object_name , counter_name , instance_name Monitoring changes in the size of the transaction log. --the default instance reports as SQLServer, but other --instances as MSSQL$InstanceName DECLARE @object_name SYSNAME SET @object_name = CASE WHEN @@servicename = 'MSSQLSERVER' THEN 'SQLServer' ELSE 'MSSQL$' + @@serviceName END + ':Databases' DECLARE @PERF_COUNTER_LARGE_RAWCOUNT INT SELECT @PERF_COUNTER_LARGE_RAWCOUNT = 65792 SELECT object_name , counter_name , instance_name , cntr_value FROM sys.dm_os_performance_counters WHERE cntr_type = @PERF_COUNTER_LARGE_RAWCOUNT AND object_name = @object_name AND counter_name IN ( 'Log Growths', 'Log Shrinks' ) AND cntr_value > 0 ORDER BY object_name , counter_name , instance_name Which deprecated features are still in use? DECLARE @object_name SYSNAME SET @object_name = CASE WHEN @@servicename = 'MSSQLSERVER' THEN 'SQLServer' ELSE 'MSSQL$' + @@serviceName END + ':Deprecated Features' DECLARE @PERF_COUNTER_LARGE_RAWCOUNT INT SELECT @PERF_COUNTER_LARGE_RAWCOUNT = 65792 SELECT object_name , counter_name , instance_name , cntr_value FROM sys.dm_os_performance_counters WHERE cntr_type = @PERF_COUNTER_LARGE_RAWCOUNT AND object_name = @object_name AND cntr_value > 0 Returning the values of ratio PerfMon counters. DECLARE @PERF_LARGE_RAW_FRACTION INT , @PERF_LARGE_RAW_BASE INT SELECT @PERF_LARGE_RAW_FRACTION = 537003264 , @PERF_LARGE_RAW_BASE = 1073939712 SELECT dopc_fraction.object_name , dopc_fraction.instance_name , dopc_fraction.counter_name , --when divisor is 0, return I return NULL to indicate --divide by 0/no values captured CAST(dopc_fraction.cntr_value AS FLOAT) / CAST(CASE dopc_base.cntr_value WHEN 0 THEN NULL ELSE dopc_base.cntr_value END AS FLOAT) AS cntr_value FROM sys.dm_os_performance_counters AS dopc_base JOIN sys.dm_os_performance_counters AS dopc_fraction ON dopc_base.cntr_type = @PERF_LARGE_RAW_BASE AND dopc_fraction.cntr_type = @PERF_LARGE_RAW_FRACTION AND dopc_base.object_name = dopc_fraction.object_name AND dopc_base.instance_name = dopc_fraction.instance_name AND ( REPLACE(dopc_base.counter_name, 'base', '') = dopc_fraction.counter_name --Worktables From Cache has "odd" name where --Ratio was left off OR REPLACE(dopc_base.counter_name, 'base', '') = ( REPLACE(dopc_fraction.counter_name, 'ratio', '') ) ) ORDER BY dopc_fraction.object_name , dopc_fraction.instance_name , dopc_fraction.counter_name Returning the current value for the buffer cache hit ratio. DECLARE @object_name SYSNAME SET @object_name = CASE WHEN @@servicename = 'MSSQLSERVER' THEN 'SQLServer' ELSE 'MSSQL$' + @@serviceName END + ':Buffer Manager' DECLARE @PERF_LARGE_RAW_FRACTION INT , @PERF_LARGE_RAW_BASE INT SELECT @PERF_LARGE_RAW_FRACTION = 537003264 , @PERF_LARGE_RAW_BASE = 1073939712 SELECT dopc_fraction.object_name , dopc_fraction.instance_name , dopc_fraction.counter_name , --when divisor is 0, return I return NULL to indicate --divide by 0/no values captured CAST(dopc_fraction.cntr_value AS FLOAT) / CAST(CASE dopc_base.cntr_value WHEN 0 THEN NULL ELSE dopc_base.cntr_value END AS FLOAT) AS cntr_value FROM sys.dm_os_performance_counters AS dopc_base JOIN sys.dm_os_performance_counters AS dopc_fraction ON dopc_base.cntr_type = @PERF_LARGE_RAW_BASE AND dopc_fraction.cntr_type = @PERF_LARGE_RAW_FRACTION AND dopc_base.object_name = dopc_fraction.object_name AND dopc_base.instance_name = dopc_fraction.instance_name AND ( REPLACE(dopc_base.counter_name, 'base', '') = dopc_fraction.counter_name --Worktables From Cache has "odd" name where --Ratio was left off OR REPLACE(dopc_base.counter_name, 'base', '') = ( REPLACE(dopc_fraction.counter_name, 'ratio', '') ) ) WHERE dopc_fraction.object_name = @object_name AND dopc_fraction.instance_name = '' AND dopc_fraction.counter_name = 'Buffer cache hit ratio' ORDER BY dopc_fraction.object_name , dopc_fraction.instance_name , dopc_fraction.counter_name Returning the values of "per second average" PerfMon counters. DECLARE @PERF_COUNTER_BULK_COUNT INT SELECT @PERF_COUNTER_BULK_COUNT = 272696576 --Holds initial state DECLARE @baseline TABLE ( object_name NVARCHAR(256) , counter_name NVARCHAR(256) , instance_name NVARCHAR(256) , cntr_value BIGINT , cntr_type INT , time DATETIME DEFAULT ( GETDATE() ) ) DECLARE @current TABLE ( object_name NVARCHAR(256) , counter_name NVARCHAR(256) , instance_name NVARCHAR(256) , cntr_value BIGINT , cntr_type INT , time DATETIME DEFAULT ( GETDATE() ) ) --capture the initial state of bulk counters INSERT INTO @baseline ( object_name , counter_name , instance_name , cntr_value , cntr_type ) SELECT object_name , counter_name , instance_name , cntr_value , cntr_type FROM sys.dm_os_performance_counters AS dopc WHERE cntr_type = @PERF_COUNTER_BULK_COUNT WAITFOR DELAY '00:00:05' --the code will work regardless of delay chosen --get the followon state of the counters INSERT INTO @current ( object_name , counter_name , instance_name , cntr_value , cntr_type ) SELECT object_name , counter_name , instance_name , cntr_value , cntr_type FROM sys.dm_os_performance_counters AS dopc WHERE cntr_type = @PERF_COUNTER_BULK_COUNT SELECT dopc.object_name , dopc.instance_name , dopc.counter_name , --ms to second conversion factor 1000 * --current value less the previous value ( ( dopc.cntr_value - prev_dopc.cntr_value ) --divided by the number of milliseconds that pass --casted as float to get fractional results. Float --lets really big or really small numbers to work / CAST(DATEDIFF(ms, prev_dopc.time, dopc.time) AS FLOAT) ) AS cntr_value --simply join on the names of the counters FROM @current AS dopc JOIN @baseline AS prev_dopc ON prev_dopc.object_name = dopc.object_name AND prev_dopc.instance_name = dopc.instance_name AND prev_dopc.counter_name = dopc.counter_name WHERE dopc.cntr_type = @PERF_COUNTER_BULK_COUNT AND 1000 * ( ( dopc.cntr_value - prev_dopc.cntr_value ) / CAST(DATEDIFF(ms, prev_dopc.time, dopc.time) AS FLOAT) ) /* default to only showing non-zero values */ <> 0 ORDER BY dopc.object_name , dopc.instance_name , dopc.counter_name Returning the values for the "average number of operations" PerfMon counters. DECLARE @PERF_AVERAGE_BULK INT , @PERF_LARGE_RAW_BASE INT SELECT @PERF_AVERAGE_BULK = 1073874176 , @PERF_LARGE_RAW_BASE = 1073939712 SELECT dopc_avgBulk.object_name , dopc_avgBulk.instance_name , dopc_avgBulk.counter_name , CAST(dopc_avgBulk.cntr_value AS FLOAT) --when divisor is 0, return NULL to indicate --divide by 0 / CAST(CASE dopc_base.cntr_value WHEN 0 THEN NULL ELSE dopc_base.cntr_value END AS FLOAT) AS cntr_value FROM sys.dm_os_performance_counters dopc_base JOIN sys.dm_os_performance_counters dopc_avgBulk ON dopc_base.cntr_type = @PERF_LARGE_RAW_BASE AND dopc_avgBulk.cntr_type = @PERF_AVERAGE_BULK AND dopc_base.object_name = dopc_avgBulk.object_name AND dopc_base.instance_name = dopc_avgBulk.instance_name --Average Wait Time has (ms) in name, --so it has handled "special" AND ( REPLACE(dopc_base.counter_name, 'base', '') = dopc_avgBulk.counter_name OR REPLACE(dopc_base.counter_name, 'base', '') = REPLACE(dopc_avgBulk.counter_name, '(ms)', '') ) ORDER BY dopc_avgBulk.object_name , dopc_avgBulk.instance_name , dopc_avgBulk.counter_name CPU configuration details. -- Hardware information from SQL Server 2008 -- (Cannot distinguish between HT and multi-core) SELECT cpu_count AS [Logical CPU Count] , hyperthread_ratio AS [Hyperthread Ratio] , cpu_count / hyperthread_ratio AS [Physical CPU Count] , physical_memory_in_bytes / 1048576 AS [Physical Memory (MB)] , sqlserver_start_time FROM sys.dm_os_sys_info ; Interrogating memory configuration. --Determine if this is a 32- or 64-bit SQL Server edition DECLARE @ServerAddressing AS TINYINT SELECT @serverAddressing = CASE WHEN CHARINDEX('64', CAST(SERVERPROPERTY('Edition') AS VARCHAR(100))) > 0 THEN 64 ELSE 32 END ; SELECT cpu_count / hyperthread_ratio AS SocketCount , physical_memory_in_bytes / 1024 / 1024 AS physical_memory_mb , virtual_memory_in_bytes / 1024 / 1024 AS sql_max_virtual_memory_mb , -- same with other bpool columns as they are page oriented. -- Multiplying by 8 takes it to 8K, then / 1024 to convert to mb bpool_committed * 8 / 1024 AS buffer_pool_committed_mb , --64 bit OS does not have limitations with addressing as 32 did CASE WHEN @serverAddressing = 32 THEN CASE WHEN virtual_memory_in_bytes / 1024 / ( 2048 * 1024 ) < 1 THEN 'off' ELSE 'on' END ELSE 'N/A on 64 bit' END AS [/3GB switch] FROM sys.dm_os_sys_info Investigating scheduler activity. -- Get Avg task count and Avg runnable task count SELECT AVG(current_tasks_count) AS [Avg Task Count] , AVG(runnable_tasks_count) AS [Avg Runnable Task Count] FROM sys.dm_os_schedulers WHERE scheduler_id < 255 AND [status] = 'VISIBLE ONLINE' ; Investigating potential disk I/O or CPU pressure. SELECT scheduler_id , cpu_id , Status , is_online , is_idle , current_tasks_count , runnable_tasks_count , current_workers_count , active_workers_count , work_queue_count , pending_disk_io_count , load_factor FROM sys.dm_os_schedulers WHERE scheduler_id < 255 AND runnable_tasks_count > 0 -- AND pending_disk_io_count > 0 Are there sufficient worker threads for the workload? SELECT AVG(work_queue_count) FROM sys.dm_os_schedulers WHERE status = 'VISIBLE ONLINE' Investigating context switching. SELECT scheduler_id , preemptive_switches_count , context_switches_count , idle_switches_count , failed_to_create_worker FROM sys.dm_os_schedulers WHERE scheduler_id < 255 Is NUMA enabled? -- Is NUMA enabled SELECT CASE COUNT(DISTINCT parent_node_id) WHEN 1 THEN 'NUMA disabled' ELSE 'NUMA enabled' END FROM sys.dm_os_schedulers WHERE parent_node_id <> 32 ; Recent CPU utilization. -- Get CPU Utilization History for last 30 minutes (in one minute intervals) -- This version works with SQL Server 2008 and SQL Server 2008 R2 only DECLARE @ts_now BIGINT = ( SELECT cpu_ticks / ( cpu_ticks / ms_ticks ) FROM sys.dm_os_sys_info ) ; SELECT TOP ( 30 ) 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 WHERE ring_buffer_type = N'RING_BUFFER_SCHEDULER_MONITOR' AND record LIKE N'%<SystemHealth>%' ) AS x ) AS y ORDER BY record_id DESC ; System memory usage. SELECT total_physical_memory_kb / 1024 AS total_physical_memory_mb , available_physical_memory_kb / 1024 AS available_physical_memory_mb , total_page_file_kb / 1024 AS total_page_file_mb , available_page_file_kb / 1024 AS available_page_file_mb , system_memory_state_desc FROM sys.dm_os_sys_memory Memory usage by the SQL Server process. SELECT physical_memory_in_use_kb , virtual_address_space_committed_kb , virtual_address_space_available_kb , page_fault_count , process_physical_memory_low , process_virtual_memory_low FROM sys.dm_os_process_memory Memory allocation in the buffer pool. -- Get total buffer usage by database SELECT DB_NAME(database_id) AS [Database Name] , COUNT(*) * 8 / 1024.0 AS [Cached Size (MB)] FROM sys.dm_os_buffer_descriptors WHERE database_id > 4 -- exclude system databases AND database_id <> 32767 -- exclude ResourceDB GROUP BY DB_NAME(database_id) ORDER BY [Cached Size (MB)] DESC ; -- Breaks down buffers by object (table, index) in the buffer pool SELECT OBJECT_NAME(p.[object_id]) AS [ObjectName] , p.index_id , COUNT(*) / 128 AS [Buffer size(MB)] , COUNT(*) AS [Buffer_count] FROM sys.allocation_units AS a INNER JOIN sys.dm_os_buffer_descriptors AS b ON a.allocation_unit_id = b.allocation_unit_id INNER JOIN sys.partitions AS p ON a.container_id = p.hobt_id WHERE b.database_id = DB_ID() AND p.[object_id] > 100 -- exclude system objects GROUP BY p.[object_id] , p.index_id ORDER BY buffer_count DESC ; Buffer pool usage. -- Buffer Pool Usage for instance SELECT TOP(20) [type], SUM(single_pages_kb) AS [SPA Mem, Kb] FROM sys.dm_os_memory_clerks GROUP BY [type] ORDER BY SUM(single_pages_kb) DESC; Which queries have requested, or have had to wait for, large memory grants? -- Shows the memory required by both running (non-null grant_time) -- and waiting queries (null grant_time) -- SQL Server 2008 version SELECT DB_NAME(st.dbid) AS [DatabaseName] , mg.requested_memory_kb , mg.ideal_memory_kb , mg.request_time , mg.grant_time , mg.query_cost , mg.dop , st.[text] FROM sys.dm_exec_query_memory_grants AS mg CROSS APPLY sys.dm_exec_sql_text(plan_handle) AS st WHERE mg.request_time < COALESCE(grant_time, '99991231') ORDER BY mg.requested_memory_kb DESC ; -- Shows the memory required by both running (non-null grant_time) -- and waiting queries (null grant_time) -- SQL Server 2005 version SELECT DB_NAME(st.dbid) AS [DatabaseName] , mg.requested_memory_kb , mg.request_time , mg.grant_time , mg.query_cost , mg.dop , st.[text] FROM sys.dm_exec_query_memory_grants AS mg CROSS APPLY sys.dm_exec_sql_text(plan_handle) AS st WHERE mg.request_time < COALESCE(grant_time, '99991231') ORDER BY mg.requested_memory_kb DESC ; Returning the cache counters. SELECT type , name , single_pages_kb , multi_pages_kb , single_pages_in_use_kb , multi_pages_in_use_kb , entries_count , entries_in_use_count FROM sys.dm_os_memory_cache_counters ORDER BY type,name; Investigating the use of the plan cache. SELECT name , type , entries_count , entries_in_use_count FROM sys.dm_os_memory_cache_counters WHERE type IN ( 'CACHESTORE_SQLCP', 'CACHESTORE_OBJCP' ) --ad hoc plans and object plans ORDER BY name , type Investigating plan reuse counts. --in a different connection, execute this all at once: USE tempdb go CREATE PROCEDURE test AS WAITFOR DELAY '00:00:30' SELECT * FROM sys.sysobjects go EXECUTE test Resetting the latch statistics. DBCC SQLPERF ('sys.dm_os_latch_stats', CLEAR); Seeking out latch waits. SELECT latch_class , waiting_requests_count AS waitCount , wait_time_ms AS waitTime , max_wait_time_ms AS maxWait FROM sys.dm_os_latch_stats ORDER BY wait_time_ms DESC Finding the top ten CPU-consuming queries SELECT TOP ( 10 ) SUBSTRING(ST.text, ( QS.statement_start_offset / 2 ) + 1, ( ( CASE statement_end_offset WHEN -1 THEN DATALENGTH(st.text) ELSE QS.statement_end_offset END - QS.statement_start_offset ) / 2 ) + 1) AS statement_text ,execution_count , total_worker_time / 1000 AS total_worker_time_ms , ( total_worker_time / 1000 ) / execution_count AS avg_worker_time_ms , total_logical_reads , total_logical_reads / execution_count AS avg_logical_reads , total_elapsed_time / 1000 AS total_elapsed_time_ms , ( total_elapsed_time / 1000 ) / execution_count AS avg_elapsed_time_ms , qp.query_plan FROM sys.dm_exec_query_stats qs CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) st CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) qp ORDER BY total_worker_time DESC ———————————————— 版权声明：本文为CSDN博主「Burgess_Liu」的原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接及本声明。 原文链接：https://blog.csdn.net/Burgess_Liu/article/details/52813727