Sql Server CPU 性能排查及优化的相关 Sql 语句，非常好的SQL语句，记录于此：
--
Begin Cpu 分析优化的相关 Sql
--
使用DMV来分析SQL Server启动以来累计使用CPU资源最多的语句。例如下面的语句就可以列出前50名。
select
c.last_execution_time,c.execution_count,c.total_logical_reads,c.total_logical_writes,c.total_elapsed_time,c.last_elapsed_time,
q.
[
text
]
from
(
select
top
50
qs.
*
from
sys.dm_exec_query_stats qs
order
by
qs.total_worker_time
desc
)
as
c
cross
apply sys.dm_exec_sql_text(plan_handle)
as
q
order
by
c.total_worker_time
desc
go
--
返回最经常运行的100条语句
SELECT
TOP
100
cp.cacheobjtype,cp.usecounts,cp.size_in_bytes,qs.statement_start_offset,qs.statement_end_offset,qt.dbid ,qt.objectid
,
SUBSTRING
(qt.
text
,qs.statement_start_offset
/
2
,
(
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
)
as
statement
FROM
sys.dm_exec_query_stats qs
cross
apply sys.dm_exec_sql_text(qs.sql_handle)
as
qt
inner
join
sys.dm_exec_cached_plans
as
cp
on
qs.plan_handle
=
cp.plan_handle
where
cp.plan_handle
=
qs.plan_handle
and
cp.usecounts
>
4
ORDER
BY
[
dbid
]
,
[
Usecounts
]
DESC
--
返回做IO数目最多的50条语句以及它们的执行计划
select
top
50
(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, statement_end_offset
as
stmt_end_offset,
substring
(sql_text.
text
, (statement_start_offset
/
2
),
case
when
(statement_end_offset
-
statement_start_offset)
/
2
<=
0
then
64000
else
(statement_end_offset
-
statement_start_offset)
/
2
end
)
as
exec_statement, sql_text.
text
,plan_text.
*
from
sys.dm_exec_query_stats
cross
apply sys.dm_exec_sql_text(sql_handle)
as
sql_text
cross
apply sys.dm_exec_query_plan(plan_handle)
as
plan_text
order
by
(total_logical_reads
+
total_logical_writes)
/
Execution_count
Desc
--
计算signal wait占整wait时间的百分比
--
指令等待 CPU 资源的时间占总时间的百分比。如果超过 25% ，说明 CPU 紧张
select
convert
(numeric(
5
,
4
),
sum
(signal_wait_time_ms)
/
sum
(wait_time_ms))
from
Sys.dm_os_wait_stats
--
计算'Cxpacket'占整wait时间的百分比
--
Cxpacket:Sql Server 在处理一句代价很大的语句，要不就是没有合适的索引或筛选条件没能筛选足够的记录，使得语句要返回大量的结果，当 >5% 说明有问题
declare
@Cxpacket
bigint
declare
@Sumwaits
bigint
select
@Cxpacket
=
wait_time_ms
from
Sys.dm_os_wait_stats
where
wait_type
=
'
Cxpacket
'
select
@Sumwaits
=
sum
(wait_time_ms)
from
Sys.dm_os_wait_stats
select
convert
(numeric(
5
,
4
),
@Cxpacket
/
@Sumwaits
)
--
查询当前数据库上所有用户表格在Row lock上发生阻塞的频率
declare
@dbid
int
select
@dbid
=
db_id
()
Select
dbid
=
database_id, objectname
=
object_name
(s.
object_id
)
, indexname
=
i.name, i.index_id
--
, partition_number
, row_lock_count, row_lock_wait_count
,
[
block %
]
=
cast
(
100.0
*
row_lock_wait_count
/
(
1
+
row_lock_count)
as
numeric(
15
,
2
))
, row_lock_wait_in_ms
,
[
avg row lock waits in ms
]
=
cast
(
1.0
*
row_lock_wait_in_ms
/
(
1
+
row_lock_wait_count)
as
numeric(
15
,
2
))
from
sys.dm_db_index_operational_stats (
@dbid
,
NULL
,
NULL
,
NULL
) s, sys.indexes i
where
objectproperty
(s.
object_id
,
'
IsUserTable
'
)
=
1
and
i.
object_id
=
s.
object_id
and
i.index_id
=
s.index_id
order
by
row_lock_wait_count
desc
--
End Cpu 分析优化的相关 Sql
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