sql server 数据库优化

  ----修改表字段长度
    Alter Table gsp039 Alter Column spmch Varchar(100) Not Null
–查询某个数据库的连接数
select count(*) from Master.dbo.SysProcesses where dbid=db_id()

–前10名其他等待类型
SELECT TOP 10 *
from sys.dm_os_wait_stats
ORDER BY wait_time_ms DESC

SELECT *FROM sys.dm_os_wait_stats WHERE wait_type like ‘PAGELATCH%’
OR wait_type like ‘LAZYWRITER_SLEEP%’

–CPU的压力
SELECT scheduler_id, current_tasks_count, runnable_tasks_count
FROM sys.dm_os_schedulers
WHERE scheduler_id < 255

–表现最差的前10名使用查询
SELECT TOP  10    ProcedureName    = t.text,
ExecutionCount   = s.execution_count,
AvgExecutionTime =  isnull ( s.total_elapsed_time / s.execution_count, 0 ),
AvgWorkerTime    = s.total_worker_time / s.execution_count,
TotalWorkerTime  = s.total_worker_time,
MaxLogicalReads  = s.max_logical_reads,
MaxPhysicalReads = s.max_physical_reads,
MaxLogicalWrites = s.max_logical_writes,
CreationDateTime = s.creation_time,
CallsPerSecond   =  isnull ( s.execution_count /  datediff (  second , s.creation_time,  getdate ()), 0 )
FROM  sys.dm_exec_query_stats s
CROSS  APPLY sys.dm_exec_sql_text( s.sql_handle )  t ORDER BY
s.max_physical_reads  DESC

SELECT SUM(signal_wait_time_ms) AS total_signal_wait_time_ms总信号等待时间 ,
SUM(wait_time_ms – signal_wait_time_ms) AS resource_wait_time_ms资源的等待时间,
SUM(signal_wait_time_ms) * 1.0 / SUM (wait_time_ms) * 100 AS [signal_wait_percent信号等待％],
SUM(wait_time_ms – signal_wait_time_ms) * 1.0 / SUM (wait_time_ms) * 100 AS [resource_wait_percent资源等待％]
FROM sys.dm_os_wait_stats
–一个信号等待时间过多对资源的等待时间那么你的CPU是目前的一个瓶颈。

–查看进程所执行的SQL语句

if (select COUNT(*) from master.dbo.sysprocesses) > 500
begin
select text,CROSS APPLY master.sys.dm_exec_sql_text(a.sql_handle) from master.sys.sysprocesses  a

end

select text,a.* from master.sys.sysprocesses  a
CROSS APPLY master.sys.dm_exec_sql_text(a.sql_handle)
where a.spid = ’51′

dbcc   inputbuffer(53)

with tb
as
(
select blocking_session_id,
session_id,db_name(database_id) as dbname,text from master.sys.dm_exec_requests  a
CROSS APPLY master.sys.dm_exec_sql_text(a.sql_handle)
),
tb1 as
(
select a.*,login_time,program_name,client_interface_name,login_name,cpu_time,memory_usage*8 as ‘memory_usage(KB)’,
total_scheduled_time,reads,writes,logical_reads
from tb a inner join master.sys.dm_exec_sessions b
on a.session_id=b.session_id
)
select a.*,connect_time,client_tcp_port,client_net_address from tb1 a inner join master.sys.dm_exec_connections b on a.session_id=b.session_id

–当前进程数
select * from master.dbo.sysprocesses
order by cpu desc

–查看当前活动的进程数
sp_who active

–查询是否由于连接没有释放引起CPU过高
select * from master.dbo.sysprocesses
where spid> 50
and waittype = 0×0000
and waittime = 0
and status = ‘sleeping ‘
and last_batch < dateadd(minute, -10, getdate())
and login_time < dateadd(minute, -10, getdate())

–强行释放空连接
select ‘kill ‘ + rtrim(spid) from master.dbo.sysprocesses
where spid> 50
and waittype = 0×0000
and waittime = 0
and status = ‘sleeping ‘
and last_batch < dateadd(minute, -60, getdate())
and login_time < dateadd(minute, -60, getdate())

–查看当前占用 cpu 资源最高的会话和其中执行的语句(及时CPU)
select spid,cmd,cpu,physical_io,memusage,
(select top 1 [text] from ::fn_get_sql(sql_handle)) sql_text
from master..sysprocesses order by cpu desc,physical_io desc
–查看缓存中重用次数少，占用内存大的查询语句（当前缓存中未释放的）–全局
SELECT TOP 100 usecounts, objtype, p.size_in_bytes,[sql].[text]
FROM sys.dm_exec_cached_plans p OUTER APPLY sys.dm_exec_sql_text (p.plan_handle) sql
ORDER BY usecounts,p.size_in_bytes desc

SELECT top 25 qt.text,qs.plan_generation_num,qs.execution_count,dbid,objectid
FROM sys.dm_exec_query_stats qs
CROSS APPLY sys.dm_exec_sql_text(sql_handle) as qt
WHERE plan_generation_num >1
ORDER BY qs.plan_generation_num

SELECT top 50 qt.text AS SQL_text ,SUM(qs.total_worker_time) AS total_cpu_time,
SUM(qs.execution_count) AS total_execution_count,
SUM(qs.total_worker_time)/SUM(qs.execution_count) AS avg_cpu_time,
COUNT(*) AS number_of_statements
FROM sys.dm_exec_query_stats qs
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) as qt
GROUP BY qt.text
ORDER BY total_cpu_time DESC –统计总的CPU时间
–ORDER BY avg_cpu_time DESC –统计平均单次查询CPU时间

– 计算可运行状态下的工作进程数量
SELECT COUNT(*) as workers_waiting_for_cpu,s.scheduler_id
FROM sys.dm_os_workers AS o
INNER JOIN sys.dm_os_schedulers AS s
ON o.scheduler_address=s.scheduler_address
AND s.scheduler_id<255
WHERE o.state=’RUNNABLE’
GROUP BY s.scheduler_id

–表空间大小查询

create table #tb(表名 sysname,记录数 int,保留空间 varchar(100),使用空间 varchar(100),索引使用空间 varchar(100),未用空间 varchar(100))
insert into #tb exec sp_MSForEachTable 'EXEC sp_spaceused ''?'''
select * from #tb
go

SELECT
表名,
记录数,
cast(ltrim(rtrim(replace(保留空间,'KB',''))) as int)/1024 保留空间MB,
cast(ltrim(rtrim(replace(使用空间,'KB',''))) as int)/1024 使用空间MB,
cast(ltrim(rtrim(replace(使用空间,'KB',''))) as int)/1024/1024.00 使用空间GB,
cast(ltrim(rtrim(replace(索引使用空间,'KB',''))) as int)/1024 索引使用空间MB,
cast(ltrim(rtrim(replace(未用空间,'KB',''))) as int)/1024 未用空间MB
FROM #tb
WHERE cast(ltrim(rtrim(replace(使用空间,'KB',''))) as int)/1024 > 0 
--order by 记录数 desc
ORDER BY 使用空间MB DESC

DROP TABLE #tb

–强行释放空连接
select ‘kill ‘ + rtrim(spid) from master.dbo.sysprocesses
where spid> 50
and waittype = 0×0000
and waittime = 0
and status = ‘sleeping ‘
and last_batch < dateadd(minute, -60, getdate())
and login_time < dateadd(minute, -60, getdate())

—-查看当前占用 cpu 资源最高的会话和其中执行的语句(及时CPU)
select spid,cmd,cpu,physical_io,memusage,
(select top 1 [text] from ::fn_get_sql(sql_handle)) sql_text
from master..sysprocesses order by cpu desc,physical_io desc

—-查看缓存中重用次数少，占用内存大的查询语句（当前缓存中未释放的）–全局
SELECT TOP 100 usecounts, objtype, p.size_in_bytes,[sql].[text]
FROM sys.dm_exec_cached_plans p OUTER APPLY sys.dm_exec_sql_text (p.plan_handle) sql
ORDER BY usecounts,p.size_in_bytes desc

SELECT top 25 qt.text,qs.plan_generation_num,qs.execution_count,dbid,objectid
FROM sys.dm_exec_query_stats qs
CROSS APPLY sys.dm_exec_sql_text(sql_handle) as qt
WHERE plan_generation_num >1
ORDER BY qs.plan_generation_num

SELECT top 50 qt.text AS SQL_text ,SUM(qs.total_worker_time) AS total_cpu_time,
SUM(qs.execution_count) AS total_execution_count,
SUM(qs.total_worker_time)/SUM(qs.execution_count) AS avg_cpu_time,
COUNT(*) AS number_of_statements
FROM sys.dm_exec_query_stats qs
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) as qt
GROUP BY qt.text
ORDER BY total_cpu_time DESC –统计总的CPU时间
–ORDER BY avg_cpu_time DESC –统计平均单次查询CPU时间

– 计算可运行状态下的工作进程数量
SELECT COUNT(*) as workers_waiting_for_cpu,s.scheduler_id
FROM sys.dm_os_workers AS o
INNER JOIN sys.dm_os_schedulers AS s
ON o.scheduler_address=s.scheduler_address
AND s.scheduler_id<255
WHERE o.state=’RUNNABLE’
GROUP BY s.scheduler_id

 

–查询是否由于连接没有释放引起CPU过高

select * from master.dbo.sysprocesses
where spid> 50
and waittype = 0×0000
and waittime = 0
and status = ‘sleeping ‘
and last_batch < dateadd(minute, -10, getdate())
and login_time < dateadd(minute, -10, getdate())