--- 平均I/O时间长的语句
USE tempdbSELECT TOP 10
(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,
SUBSTRING(st.text, statement_start_offset/2 + 1,  (CASE WHEN statement_end_offset = -1   THEN LEN(CONVERT(nvarchar(MAX),text)) * 2   ELSE statement_end_offset   END - statement_start_offset)/2) ,st.text --FROM sys.dm_exec_sql_text(sql_handle)) AS query_text
FROM sys.dm_exec_query_stats   AS qs
CROSS APPLY SYS.dm_exec_sql_text(qs.sql_handle) AS stORDER BY (total_logical_reads + total_logical_writes)/execution_count DESC  /*
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。
摘自msdn , sys.dm_exec_sql_text
*/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;---------------------------------------
/*
--CPU 开销较大的 --摘自MSDN
*/USE AdventureWorks;
GO
SELECT TOP 5 query_stats.query_hash AS "Query Hash", SUM(query_stats.total_worker_time) / SUM(query_stats.execution_count) AS "Avg CPU Time",MIN(query_stats.statement_text) AS "Statement Text"
FROM (SELECT QS.*, SUBSTRING(ST.text, (QS.statement_start_offset/2) + 1,((CASE statement_end_offset WHEN -1 THEN DATALENGTH(st.text)ELSE QS.statement_end_offset END - QS.statement_start_offset)/2) + 1) AS statement_textFROM sys.dm_exec_query_stats AS QSCROSS APPLY sys.dm_exec_sql_text(QS.sql_handle) as ST) as query_stats
GROUP BY query_stats.query_hash
ORDER BY 2 DESC;
GO/*
另外一种方法计算平均CPU的值  --摘自MSDN sys.dm_exec_sql_text
*/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_offsetWHEN -1 THEN DATALENGTH(st.text)ELSE qs.statement_end_offsetEND - 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;/*
开销较大的查询   ---黄钊吉
*/
SELECT  ss.SUM_execution_count ,
t.text ,
ss.SUM_total_elapsed_time ,
ss.sum_total_worker_time ,
ss.sum_total_logical_reads ,
ss.sum_total_logical_writes
FROM    ( SELECT    S.plan_handle ,
SUM(s.execution_count) SUM_Execution_count ,
SUM(s.total_elapsed_time) SUM_total_elapsed_time ,
SUM(s.total_worker_time) SUM_total_worker_time ,
SUM(s.total_logical_reads) SUM_total_logical_reads ,
SUM(s.total_logical_writes) SUM_total_logical_writes
FROM    sys.dm_exec_query_stats s
GROUP BY  S.plan_handle
)   AS ss
CROSS APPLY sys.dm_exec_sql_text(ss.plan_handle) t
ORDER  BY sum_total_logical_reads DESC