sql测试及性能分析方法

sql测试及性能分析方法


一、sql缓存的处理
1.清除缓存


--清除所有缓存
DBCC DROPCLEANBUFFERS 


--清除存储过程缓存 
DBCC FREEPROCCACHE 


--清除会话缓存
DBCC FREESESSIONCACHE 
 
--清除系统缓存
DBCC FREESYSTEMCACHE 


---清空特定缓存存储区中的执行计划
DBCC FREESYSTEMCACHE(<cachestore>) -- 'ALL', pool_name, 'Object Plans', 'SQL Plans', 'Bound Trees'
GO


--将当前数据库的全部脏页写入磁盘。
CHECKPOINT 


--查看数据库打开事务状态等
DBCC OPENTRAN


--查看全部游标 
sp_cursor_list 

示例：

CHECKPOINT


DBCC DROPCLEANBUFFERS


DBCC FREEPROCCACHE


DBCC FREESYSTEMCACHE ( 'ALL' ) 

--要接着执行你的查询,不然SQLServer会时刻的自动往缓存里读入最有可能需要的数据页.

2.查看缓存里当前的内容

SELECT * FROM sys.dm_os_buffer_descriptors where page_type IN ('DATA_Page','INDEX_Page') ORDER BY row_count DESC

二、查看查询计划

文本方式查看查询计划

a、只开启执行计划，不包括详细的评估值

SET SHOWPLAN_TEXT ON

b、开启所有的执行计划明细，包括各个属性的评估值 
SET SHOWPLAN_ALL ON 


XML方式展现查询计划

SET STATISTICS XML ON 

三、查看执行语句花费的时间


1.手工添加语句，计算执行时间来查看执行语句花费了的时间

declare @d datetime
set @d=getdate()
/*你的SQL脚本开始*/
SELECT [TestCase] FROM [TestCaseSelect] 
/*你的SQL脚本结束*/
select [语句执行花费时间(毫秒)]=datediff(ms,@d,getdate())

2.通过设置STATISTICS来查看时间
SET STATISTICS PROFILE ON：显示分析、编译和执行查询所需的时间（以毫秒为单位）。 
SET STATISTICS IO ON：报告与语句内引用的每个表的扫描数、逻辑读取数（在高速缓存中访问的页数）和物理读取数（访问磁盘的次数）有关的信息。
SET STATISTICS TIME ON：显示每个查询执行后的结果集，代表查询执行的配置文件。


使用方法：打开SQL SERVER 查询分析器，输入以下语句：

SET STATISTICS PROFILE ON 
SET STATISTICS IO ON 
SET STATISTICS TIME ON 
GO /*--你的SQL脚本开始*/
SELECT [TestCase] FROM [TestCaseSelect] 
GO /*--你的SQL脚本结束*/
SET STATISTICS PROFILE OFF 
SET STATISTICS IO OFF 
SET STATISTICS TIME OFF

四、内存

--内存使用情况
SELECT * FROM sys.dm_os_performance_counters  
WHERE counter_name IN('Target Server Memory (KB)','Total Server Memory (KB)')  

-- 内存状态  
DBCC MemoryStatus  

--查看最小最大内存  
SELECT configuration_idas id,name as 名称,minimum as配置最小值, maximumas 最大值,  

is_dynamic as 是否动态值, is_advanced as 是否优先, value_in_use AS 运行值,  

description as 描述 FROM sys.configurations 


--分类查看缓存所占用的内存
select * from sys.dm_os_memory_cache_counters




--示例：通过动态调整 Sql Server可用的物理内存设置来强制释放内存 

CREATE procedure [dbo].ClearMemory   
as  

begin 

--清除所有缓存 

DBCC DROPCLEANBUFFERS 

--打开高级配置 

exec sp_configure'show advanced options', 1 

--设置最大内存值，清除现有缓存空间 

exec sp_configure'max server memory', 256 

EXEC ('RECONFIGURE') 

--设置等待时间 

WAITFOR DELAY '00:00:01' 

--重新设置最大内存值 

EXEC  sp_configure'max server memory',4096 

EXEC ('RECONFIGURE') 

--关闭高级配置 

exec sp_configure'show advanced options',0 

GO 

五、执行计划


执行计划相关系统视图
--1.缓存的每一个对象返回一行，包括缓存计划的类型、缓存引用的对象、缓存计划占用的空间、被使用次数、以及创建时间等
SELECT * FROM sys.syscacheobjects;
--2.缓存的每个查询计划返回一行，包括执行计划被使用的次数、执行计划的大小、内存地址、执行计划的类型、语句等
SELECT * FROM sys.dm_exec_cached_plans;
GO
---3.返回由指定的 sql_handle 标识的 SQL 批处理的文本
/*其中sql_handle来自:
sys.dm_exec_query_stats
sys.dm_exec_requests
sys.dm_exec_cursors
sys.dm_exec_xml_handles
sys.dm_exec_query_memory_grants
sys.dm_exec_connections
plan_handle来自:sys.dm_exec_cached_plans
*/ 
SELECT * FROM sys.dm_exec_sql_text(sql_handle | plan_handle);
GO
--4.以 XML 格式返回计划句柄指定的批查询的显示计划，主要接受来自sys.dm_exec_cached_plans的plan_handle句柄
SELECT * FROM sys.dm_exec_query_plan(plan_handle);
GO
--5.每个计划属性返回一行，主要接受来自sys.dm_exec_cached_plans的plan_handle句柄
SELECT * FROM sys.dm_exec_plan_attributes(plan_handle);
GO
--6.针对每个 Transact-SQL 执行计划、公共语言运行时 (CLR) 执行计划和与计划关联的游标返回一行,，主要接受来自sys.dm_exec_cached_plans的plan_handle句柄
SELECT * FROM sys.dm_exec_cached_plan_dependent_objects(plan_handle);
 
--7.返回缓存查询计划的聚合性能统计信息。缓存计划中的每个查询语句在该视图中对应一行，并且行的生存期与计划本身相关联。在从缓存删除计划时，也将从该视图中删除对应行。*/
--该系统视图针对每一个缓存中的执行计划统计其执行时间、物理、逻辑操作等信息
SELECT * FROM sys.dm_exec_query_stats




示例：根据被缓存的执行计划找到数据库中耗时最长的20个查询语句

SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED 
SELECT TOP 20 
  CAST(qs.total_elapsed_time / 1000000.0 AS DECIMAL(28, 2)) 
                                     AS [Total Duration (s)] 
  , CAST(qs.total_worker_time * 100.0 / qs.total_elapsed_time 
                               AS DECIMAL(28, 2)) AS [% CPU] 
  , CAST((qs.total_elapsed_time - qs.total_worker_time)* 100.0 / 
        qs.total_elapsed_time AS DECIMAL(28, 2)) AS [% Waiting] 
  , qs.execution_count 
  , CAST(qs.total_elapsed_time / 1000000.0 / qs.execution_count 
                AS DECIMAL(28, 2)) AS [Average Duration (s)] 
  , 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 
WHERE qs.total_elapsed_time > 0 
ORDER BY qs.total_elapsed_time DESC

六、常用监控性能DMV & DMF

DMV（Dynamic Management Views，动态管理视图）其实就是SQL Server内核的元数据，
当查询在SQL Server中运行时，SQL Server会自动的将此次活动的相关信息记录下来，并且保存在内存之中，这些活动信息，就称之为：DMV。
通过对内部的元数据的分析，我们快速而准确获取很多与SQL Server内部相关的信息，从而进行性能分析。


DMF（Dynamic Management Functions），可以简单的将DMF理解为SQL Server内部的一系列函数。


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

--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



--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


--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%'


--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


--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

--查找生成最多 I/O 的前五个请求/批处理。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

--查看数据库数据文件以及磁盘的空间情况
SELECT DB_NAME(df.database_id) as dbName,
 physical_name AS DataFile,
 size AS FileSize,
 volume_mount_point AS Drive,
 CAST(total_bytes/1024/1024/1024 AS VARCHAR) + ' GB' AS DriveSize,
 CAST(available_bytes/1024/1024/ 1024 AS VARCHAR) + ' GB'  AS SpaceAvailable
FROM sys.master_files df
CROSS APPLY sys.dm_os_volume_stats(df.database_id, df.file_id) ovs
where DB_NAME(df.database_id)='DEMO'

参考：
http://www.cnblogs.com/qanholas/archive/2011/05/06/2038543.html
http://blog.youkuaiyun.com/dcx903170332/article/details/45917387
http://www.jb51.net/article/19324.htm
http://blog.youkuaiyun.com/dinglang_2009/article/details/46480859
http://www.sqlserver-dba.com/dmv/