SQL 性能分析

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 last_worker_time desc,s1.sql_handle, s1.statement_start_offset, s1.statement_end_offset;