SQLServer 常用监控性能DMV & DMF

-- 查看性能记数器

SELECT * FROM sys.dm_os_performance_counters

-- 执行过的线程所遇到的所有等待(不是当前正在运行的线程, 为自上次重置统计信息或启动服务器以来累积的数据),可分析靠前的几个等待较高的事件。

select * from sys.dm_os_wait_stats order by wait_time_ms desc

-- 重置该动态视图

DBCC SQLPERF ('sys.dm_os_wait_stats', CLEAR);

GO

-- 正在等待某些资源的任务的等待队列

select * from sys.dm_os_waiting_tasks order by wait_duration_ms desc

内存使用：  

查看当前由 SQL Server 分配的内存对象(KB): select sum((page_size_in_bytes/1024)*max_pages_allocated_count) from sys.dm_os_memory_objects;

查看系统内存当前信息: select * from sys.dm_os_sys_memory (这个动态视图只在sql 2008中才有)

select

cpu_count,

hyperthread_ratio,

scheduler_count,

physical_memory_in_bytes / 1024 / 1024 as physical_memory_mb,

virtual_memory_in_bytes / 1024 / 1024 as virtual_memory_mb,

bpool_committed * 8 / 1024 as bpool_committed_mb,

bpool_commit_target * 8 / 1024 as bpool_target_mb,

bpool_visible * 8 / 1024 as bpool_visible_mb

from sys.dm_os_sys_info

限制SQL Server使用的最小,最大内存(MB)：

sp_configure 'show advanced options', 1;

GO

RECONFIGURE;

GO

sp_configure 'min server memory', 300;

GO

sp_configure 'max server memory', 850;

GO

RECONFIGURE;

GO

CPU使用情况:

SELECT TOP 50

total_worker_time/execution_count AS '每次执行占用CPU(微秒)',

execution_count       as '执行次数',

total_worker_time     as '总共占用CPU(微秒)',

creation_time         as '创建时间',

last_execution_time   as '最后执行时间',

min_worker_time       as '最低每次占用CPU',

max_worker_time       as '最高每次占用cpu',

total_physical_reads  as '总共io物理读取次数',

total_logical_reads   as '总共逻辑读取次数',

total_logical_writes  as '总共逻辑写次数',

total_elapsed_time    as '完成此计划的执行所占用的总时间(微秒)',

(SELECT SUBSTRING(text,statement_start_offset/2,(CASE WHEN statement_end_offset = -1 then LEN(CONVERT(nvarchar(max), text)) * 2 ELSE statement_end_offset end -statement_start_offset)/2) FROM sys.dm_exec_sql_text(sql_handle)) AS 'SQL内容'

FROM sys.dm_exec_query_stats

ORDER BY 1 DESC

--下面的查询显示SQL 等待分析和前10 个等待的资源

select top 10 *

from sys.dm_os_wait_stats

where wait_type not in ('CLR_SEMAPHORE','LAZYWRITER_SLEEP','RESOURCE_QUEUE','SLEEP_TASK','SLEEP_SYSTEMTASK','WAITFOR')

order by wait_time_ms desc;

SQL Server中的活动会话数:

exec   sp_who   'active'

print @@rowcount

SQL Server等待情况

select * from sys.dm_os_waiting_tasks ; --当前等待事件

select * from sys.dm_os_wait_stats  --历史等待次数,是sqlserver启动后的累计值,需使用下一条语句清空

DBCC SQLPERF ('sys.dm_os_wait_stats', CLEAR);

找出进程阻塞:

运行下面的查询可确定阻塞的会话

select blocking_session_id, wait_duration_ms, session_id from

sys.dm_os_waiting_tasks

where blocking_session_id is not null

spid 正在阻塞另一个 spid，可在数据库中创建以下存储过程，然后执行该存储过程。此存储过程会报告此阻塞情况。键入 sp_who 可找出 @spid；@spid 是可选参数。

create proc dbo.sp_block (@spid bigint=NULL)

as

select

   t1.resource_type,

   'database'=db_name(resource_database_id),

   'blk object' = t1.resource_associated_entity_id,

   t1.request_mode,

   t1.request_session_id,

   t2.blocking_session_id    

from

   sys.dm_tran_locks as t1,

   sys.dm_os_waiting_tasks as t2

where

   t1.lock_owner_address = t2.resource_address and

   t1.request_session_id = isnull(@spid,t1.request_session_id)

以下是使用此存储过程的示例。

exec sp_block

exec sp_block @spid = 7

select sum((page_size_in_bytes/1024)*max_pages_allocated_count) from sys.dm_os_memory_objects;

select * from sys.dm_os_sys_info;

select * from sys.dm_os_performance_counters

A. 获取有关按平均 CPU 时间排在最前面的五个查询的信息

以下示例返回前五个查询的 SQL 语句文本和平均 CPU 时间。

SELECT TOP 5 total_worker_time/execution_count AS [Avg CPU Time],

   SUBSTRING(st.text, (qs.statement_start_offset/2)+1,

       ((CASE qs.statement_end_offset

         WHEN -1 THEN DATALENGTH(st.text)

        ELSE qs.statement_end_offset

        END - qs.statement_start_offset)/2) + 1) AS statement_text

FROM sys.dm_exec_query_stats AS qs

CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) AS st

ORDER BY total_worker_time/execution_count DESC;

B. 提供批处理执行统计信息

以下示例返回按批执行的 SQL 查询的文本，并提供有关它们的统计信息。

SELECT s2.dbid,

   s1.sql_handle,  

   (SELECT TOP 1 SUBSTRING(s2.text,statement_start_offset / 2+1 ,

     ( (CASE WHEN statement_end_offset = -1

        THEN (LEN(CONVERT(nvarchar(max),s2.text)) * 2)

        ELSE statement_end_offset END)  - statement_start_offset) / 2+1))  AS sql_statement,

   execution_count,

   plan_generation_num,

   last_execution_time,  

   total_worker_time,

   last_worker_time,

   min_worker_time,

   max_worker_time,

   total_physical_reads,

   last_physical_reads,

   min_physical_reads,  

   max_physical_reads,  

   total_logical_writes,

   last_logical_writes,

   min_logical_writes,

   max_logical_writes  

FROM sys.dm_exec_query_stats AS s1

CROSS APPLY sys.dm_exec_sql_text(sql_handle) AS s2  

WHERE s2.objectid is null

ORDER BY s1.sql_handle, s1.statement_start_offset, s1.statement_end_offset;

-- 数据库文件性能,文件io性能统计(必须重启sql server服务,才能清零该计数器)

select DB_NAME(database_id) DB_NAME, file_id,io_stall_read_ms ,num_of_reads

,cast(io_stall_read_ms/(1.0+num_of_reads) as numeric(10,1)) as 'avg_read_stall_ms'

,io_stall_write_ms,num_of_writes

,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'

from sys.dm_io_virtual_file_stats(null,null)

order by avg_io_stall_ms desc;

-- 查看分区表money，各个分区的行数和边界值.

select partition = $partition.分区函数名(userid)

     ,rows      = count(*)

     ,minval    = min(userid)

     ,maxval    = max(userid)

from dbo.money with(nolock)

group by $partition.分区函数名(userid)

order by partition;

-- 数据库文件性能,文件io性能统计(必须重启sql server服务,才能清零该计数器),

SELECT DB_NAME(vfs.DbId) DatabaseName, mf.name,

mf.physical_name, vfs.BytesRead, vfs.BytesWritten,

vfs.IoStallMS, vfs.IoStallReadMS, vfs.IoStallWriteMS,

vfs.NumberReads, vfs.NumberWrites,

(Size*8)/1024 Size_MB

FROM ::fn_virtualfilestats(NULL,NULL) vfs

INNER JOIN sys.master_files mf ON mf.database_id = vfs.DbId

AND mf.FILE_ID = vfs.FileId

GO

-- 性能计数器动态视图,  和使用windows性能计数器效果一致。

SELECT [counter_name], [cntr_value] FROM sys.dm_os_performance_counters

 WHERE ([instance_name] = '' OR [instance_name] = '_Total') AND (

        ([object_name] LIKE ('%Plan Cache%') AND [counter_name] IN

         ('Cache Hit Ratio', 'Cache Hit Ratio Base')) OR

        ([object_name] LIKE ('%Buffer Manager%') AND [counter_name] IN

         ('Buffer Cache Hit Ratio', 'Buffer Cache Hit Ratio Base', 'Page reads/sec', 'Page writes/sec')) OR

        ([object_name] LIKE ('%General Statistics%') AND [counter_name] IN

         ('Active Temp Tables', 'User Connections')) OR

        ([object_name] LIKE ('%Databases%') AND [counter_name] IN

         ('Transactions/sec', 'Log Cache Hit Ratio', 'Log Cache Hit Ratio Base', 'Log Flushes/sec',

           'Log Bytes Flushed/sec', 'Backup/Restore Throughput/sec')) OR

        ([object_name] LIKE ('%Access Methods%') AND [counter_name] IN

         ('Full Scans/sec', 'Range Scans/sec', 'Probe Scans/sec', 'Index Searches/sec', 'Page Splits/sec')) OR

        ([object_name] LIKE ('%Memory Manager%') AND [counter_name] IN

         ('Target Server Memory (KB)', 'Target Server Memory(KB)', 'Total Server Memory (KB)')) OR

        ([object_name] LIKE ('%SQL Statistics%') AND [counter_name] IN

         ('SQL Compilations/sec', 'SQL Re-Compilations/sec'))

        )

--查看IO状况

SELECT TOP 20

 [Total IO] = (qs.total_logical_reads + qs.total_logical_writes)

 , [Average IO] = (qs.total_logical_reads + qs.total_logical_writes) /

                                           qs.execution_count

 , qs.execution_count

 , SUBSTRING (qt.text,(qs.statement_start_offset/2) + 1,      

 ((CASE WHEN qs.statement_end_offset = -1

   THEN LEN(CONVERT(NVARCHAR(MAX), qt.text)) * 2

   ELSE qs.statement_end_offset

   END - qs.statement_start_offset)/2) + 1) AS [Individual Query]

 , qt.text AS [Parent Query]

 , DB_NAME(qt.dbid) AS DatabaseName

 , qp.query_plan

FROM sys.dm_exec_query_stats qs

CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) as qt

CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) qp

ORDER BY [Total IO] DESC

常规服务器动态管理对象包括：

dm_db_*：数据库和数据库对象

dm_exec_*：执行用户代码和关联的连接

dm_os_*：内存、锁定和时间安排

dm_tran_*：事务和隔离

dm_io_*：网络和磁盘的输入/输出

此部分介绍为监控 SQL Server 运行状况而针对这些动态管理视图和函数运行的一些常用查询。

下面的查询显示 CPU 平均占用率最高的前 50 个 SQL 语句。

SELECT TOP 50

total_worker_time/execution_count AS [Avg CPU Time],

(SELECT SUBSTRING(text,statement_start_offset/2,(CASE WHEN statement_end_offset = -1 then LEN(CONVERT(nvarchar(max), text)) * 2 ELSE statement_end_offset end -statement_start_offset)/2) FROM sys.dm_exec_sql_text(sql_handle)) AS query_text, *

FROM sys.dm_exec_query_stats

ORDER BY [Avg CPU Time] DESC

下面的查询显示一些可能占用大量 CPU 使用率的运算符（例如 ‘%Hash Match%’、‘%Sort%’）以找出可疑对象。

select *

from

     sys.dm_exec_cached_plans

     cross apply sys.dm_exec_query_plan(plan_handle)

where

     cast(query_plan as nvarchar(max)) like '%Sort%'

     or cast(query_plan as nvarchar(max)) like '%Hash Match%'

运行下面的 DMV 查询以查看 CPU、计划程序内存和缓冲池信息。

select

cpu_count,

hyperthread_ratio,

scheduler_count,

physical_memory_in_bytes / 1024 / 1024 as physical_memory_mb,

virtual_memory_in_bytes / 1024 / 1024 as virtual_memory_mb,

bpool_committed * 8 / 1024 as bpool_committed_mb,

bpool_commit_target * 8 / 1024 as bpool_target_mb,

bpool_visible * 8 / 1024 as bpool_visible_mb

from sys.dm_os_sys_info

下面的示例查询显示已重新编译的前 25 个存储过程。plan_generation_num 指示该查询已重新编译的次数。

select top 25

sql_text.text,

sql_handle,

plan_generation_num,

execution_count,

dbid,

objectid

from sys.dm_exec_query_stats a

cross apply sys.dm_exec_sql_text(sql_handle) as sql_text

where plan_generation_num > 1

order by plan_generation_num desc

下面的 DMV 查询可用于查找哪些批处理/请求生成的 I/O 最多。如下所示的 DMV 查询可用于查找可生成最多 I/O 的前五个请求。调整这些查询将提高系统性能。

select top 5

   (total_logical_reads/execution_count) as avg_logical_reads,

   (total_logical_writes/execution_count) as avg_logical_writes,

   (total_physical_reads/execution_count) as avg_phys_reads,

    Execution_count,

   statement_start_offset as stmt_start_offset,

   sql_handle,

   plan_handle

from sys.dm_exec_query_stats  

order by  (total_logical_reads + total_logical_writes) Desc