MSSQL性能监控SQL语句

1、sys.dm_exec_query_stats
SELECT s2.dbid, 
    (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.total_worker_time desc

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