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/*Microsoft SQL Server 2005 提供了一些工具来监控数据库。方法之一是动态管理视图。动态管理视图 (DMV) 和动态管理函数 (DMF) 返回的服务器状态信息可用于监控服务器实例的运行状况、诊断问题和优化性能。
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常规服务器动态管理对象包括:
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dm_db_*:数据库和数据库对象
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dm_exec_*:执行用户代码和关联的连接
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dm_os_*:内存、锁定和时间安排
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dm_tran_*:事务和隔离
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dm_io_*:网络和磁盘的输入/输出
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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。
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*/
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SELECT
*
FROM
sys.system_objects
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WHERE
name
LIKE
'dm_%'
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ORDER
BY
name
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SELECT
TOP
50
029
SUM
(qs.total_worker_time)
AS
total_cpu_time,
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SUM
(qs.execution_count)
AS
total_execution_count,
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COUNT
(*)
AS
number_of_statements,
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qs.sql_handle
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FROM
sys.dm_exec_query_stats
AS
qs
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GROUP
BY
qs.sql_handle
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ORDER
BY
SUM
(qs.total_worker_time)
DESC
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SELECT
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total_cpu_time,
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total_execution_count,
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number_of_statements,
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s2.text
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FROM
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(
SELECT
TOP
50
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SUM
(qs.total_worker_time)
AS
total_cpu_time,
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SUM
(qs.execution_count)
AS
total_execution_count,
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COUNT
(*)
AS
number_of_statements,
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qs.sql_handle
050
051
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FROM
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sys.dm_exec_query_stats
AS
qs
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GROUP
BY
qs.sql_handle
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ORDER
BY
SUM
(qs.total_worker_time)
DESC
)
AS
stats
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CROSS
APPLY sys.dm_exec_sql_text(stats.sql_handle)
AS
s2
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SELECT
TOP
50
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total_worker_time/execution_count
AS
[
Avg
CPU
Time
],
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(
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, *
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FROM
sys.dm_exec_query_stats
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ORDER
BY
[
Avg
CPU
Time
]
DESC
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select
*
from
sys.dm_exec_query_optimizer_info
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where
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counter =
'optimizations'
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or
counter =
'elapsed time'
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select
top
25
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sql_text.text,
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sql_handle,
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plan_generation_num,
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execution_count,
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dbid,
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objectid
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from
sys.dm_exec_query_stats a
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cross
apply sys.dm_exec_sql_text(sql_handle)
as
sql_text
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where
plan_generation_num > 1
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order
by
plan_generation_num
desc
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/*效率较低的查询计划可能增大 CPU 占用率。
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下面的查询显示哪个查询占用了最多的 CPU 累计使用率。
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*/
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SELECT
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highest_cpu_queries.plan_handle,
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highest_cpu_queries.total_worker_time,
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q.dbid,
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q.objectid,
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q.number,
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q.encrypted,
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q.[text]
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from
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(
select
top
50
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qs.plan_handle,
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qs.total_worker_time
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from
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sys.dm_exec_query_stats qs
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order
by
qs.total_worker_time
desc
)
as
highest_cpu_queries
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cross
apply sys.dm_exec_sql_text(plan_handle)
as
q
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order
by
highest_cpu_queries.total_worker_time
desc
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select
*
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from
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sys.dm_exec_cached_plans
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cross
apply sys.dm_exec_query_plan(plan_handle)
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where
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cast
(query_plan
as
nvarchar(
max
))
like
'%Sort%'
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or
cast
(query_plan
as
nvarchar(
max
))
like
'%Hash Match%'
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/*
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如果已检测到效率低下并导致 CPU 占用率较高的查询计划,请对该查询中涉及的表运行
UPDATE
STATISTICS
以查看该问题是否仍然存在。然后,收集相关数据并将此问题报告给 PerformancePoint Planning 支持人员。
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如果您的系统存在过多的编译和重新编译,可能会导致系统出现与 CPU 相关的性能问题。
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您可以运行下面的 DMV 查询来找出过多的编译/重新编译。
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*/
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select
*
from
sys.dm_exec_query_optimizer_info
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where
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counter =
'optimizations'
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or
counter =
'elapsed time'
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sp_configure
'show advanced options'
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go
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sp_configure
'show advanced options'
, 1
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go
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reconfigure
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go
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sp_configure
'awe_enabled'
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go
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sp_configure
'min server memory'
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go
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sp_configure
'max server memory'
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go
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sp_configure
'min memory per query'
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go
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sp_configure
'query wait'
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go
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select
161
cpu_count,
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hyperthread_ratio,
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scheduler_count,
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physical_memory_in_bytes / 1024 / 1024
as
physical_memory_mb,
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virtual_memory_in_bytes / 1024 / 1024
as
virtual_memory_mb,
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bpool_committed * 8 / 1024
as
bpool_committed_mb,
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bpool_commit_target * 8 / 1024
as
bpool_target_mb,
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bpool_visible * 8 / 1024
as
bpool_visible_mb
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from
sys.dm_os_sys_info
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/*I/O 瓶颈
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检查闩锁等待统计信息以确定 I/O 瓶颈。运行下面的 DMV 查询以查找 I/O 闩锁等待统计信息
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*/
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select
wait_type, waiting_tasks_count, wait_time_ms, signal_wait_time_ms, wait_time_ms / waiting_tasks_count
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from
sys.dm_os_wait_stats
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where
wait_type
like
'PAGEIOLATCH%'
and
waiting_tasks_count > 0
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order
by
wait_type
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/*如果 waiting_task_counts 和 wait_time_ms 与正常情况相比有显著变化,则可以确定存在 I/O 问题。获取 SQL Server 平稳运行时性能计数器和主要 DMV 查询输出的基线非常重要。
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这些 wait_types 可以指示您的 I/O 子系统是否遇到瓶颈。
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使用以下 DMV 查询来查找当前挂起的 I/O 请求。请定期执行此查询以检查 I/O 子系统的运行状况,并隔离 I/O 瓶颈中涉及的物理磁盘。
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*/
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select
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database_id,
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file_id,
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io_stall,
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io_pending_ms_ticks,
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scheduler_address
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from
sys.dm_io_virtual_file_stats(
NULL
,
NULL
)t1,
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sys.dm_io_pending_io_requests
as
t2
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where
t1.file_handle = t2.io_handle
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/*
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在正常情况下,该查询通常不返回任何内容。如果此查询返回一些行,则需要进一步调查。
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您还可以执行下面的 DMV 查询以查找 I/O 相关查询。
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*/
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select
top
5 (total_logical_reads/execution_count)
as
avg_logical_reads,
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(total_logical_writes/execution_count)
as
avg_logical_writes,
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(total_physical_reads/execution_count)
as
avg_physical_reads,
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Execution_count, statement_start_offset, p.query_plan, q.text
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from
sys.dm_exec_query_stats
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cross
apply sys.dm_exec_query_plan(plan_handle) p
208
cross
apply sys.dm_exec_sql_text(plan_handle)
as
q
209
order
by
(total_logical_reads + total_logical_writes)/execution_count
Desc
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212
213
214
Code
215
select
top
5
216
(total_logical_reads/execution_count)
as
avg_logical_reads,
217
(total_logical_writes/execution_count)
as
avg_logical_writes,
218
(total_physical_reads/execution_count)
as
avg_phys_reads,
219
Execution_count,
220
statement_start_offset
as
stmt_start_offset,
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sql_handle,
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plan_handle
223
from
sys.dm_exec_query_stats
224
order
by
(total_logical_reads + total_logical_writes)
Desc
225
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/*阻塞
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运行下面的查询可确定阻塞的会话。
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*/
229
select
blocking_session_id, wait_duration_ms, session_id
from
230
sys.dm_os_waiting_tasks
231
where
blocking_session_id
is
not
null
232
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234
235
dbcc INPUTBUFFER(87)
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237
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select
top
10 *
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from
sys.dm_os_wait_stats
241
242
order
by
wait_time_ms
desc
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/*若要找出哪个 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。
245
*/
246
create
proc dbo.sp_block (@spid
bigint
=
NULL
)
247
as
248
select
249
t1.resource_type,
250
'database'
=db_name(resource_database_id),
251
'blk object'
= t1.resource_associated_entity_id,
252
t1.request_mode,
253
t1.request_session_id,
254
t2.blocking_session_id
255
from
256
sys.dm_tran_locks
as
t1,
257
sys.dm_os_waiting_tasks
as
t2
258
where
259
t1.lock_owner_address = t2.resource_address
and
260
t1.request_session_id =
isnull
(@spid,t1.request_session_id)
261
262
/*以下是使用此存储过程的示例。*/
263
exec
sp_block
264
exec
sp_block @spid = 7
265
266
SELECT
*
FROM
dbo.Orders
267
268
SELECT
customerID ,EmployeeID ,ShippedDate ,
COUNT
(*)
AS
numorders
269
FROM
dbo.Orders
270
WHERE
orderdate >=
'19980504'
271
AND
orderdate <=
'19980506'
272
GROUP
BY
customerID ,EmployeeID ,ShippedDate
273
WITH
CUBE