常用SQL语句

--Gives you the top 25 stored procedures that have been recompiled.

select top 25 sql_text.text, sql_handle, plan_generation_num,  execution_count,
    dbid,  objectid
into DMV_Top25_Recompile_Commands
from sys.dm_exec_query_stats a
    cross apply sys.dm_exec_sql_text(sql_handle) as sql_text
where plan_generation_num >1
order by plan_generation_num desc
go

-- sys.dm_os_wait_stats
select *
into DMV_dm_os_wait_stats
from  sys.dm_os_wait_stats 
go

--Top 50 IO contributer.
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,
    sql_handle,
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_handle, plan_text.*
into DMV_Top50_IO
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
go

--Returns current low-level I/O, locking, latching, and access method activity for each partition of a table or index in the database.
SELECT *
into DMV_dm_db_index_operational_stats
FROM sys.dm_db_index_operational_stats(NULL, NULL, NULL, NULL);
GO

--Calculate Average Stalls per database file
select database_id, file_id
 ,io_stall_read_ms
 ,num_of_reads
 ,cast(io_stall_read_ms/(1.0+num_of_reads) as numeric(10,1)) as 'avg_read_stall_ms'
 ,io_stall_write_ms
 ,num_of_writes
 ,cast(io_stall_write_ms/(1.0+num_of_writes) as numeric(10,1)) as 'avg_write_stall_ms'
 ,io_stall_read_ms + io_stall_write_ms as io_stalls
 ,num_of_reads + num_of_writes as total_io
 ,cast((io_stall_read_ms+io_stall_write_ms)/(1.0+num_of_reads + num_of_writes) as numeric(10,1)) as 'avg_io_stall_ms'
into DVM_File_Average_Stalls 
from sys.dm_io_virtual_file_stats(null,null)
order by avg_io_stall_ms desc

-- Tempdb.
-- An overview query.

Select
    SUM (user_object_reserved_page_count)*8 as user_objects_kb,
    SUM (internal_object_reserved_page_count)*8 as internal_objects_kb,
    SUM (version_store_reserved_page_count)*8  as version_store_kb,
    SUM (unallocated_extent_page_count)*8 as freespace_kb
into DMV_Tempdb_Overall_Usage
From sys.dm_db_file_space_usage
Where database_id = 2
go

-- Determine tempdb space used by Task

SELECT t1.session_id,
(t1.internal_objects_alloc_page_count + task_alloc)
 as allocated,
(t1.internal_objects_dealloc_page_count + task_dealloc) as deallocated
into DMV_Tempdb_Usage_By_Session
from sys.dm_db_session_space_usage as t1,
(select session_id,
 sum(internal_objects_alloc_page_count)
  as task_alloc,
 sum (internal_objects_dealloc_page_count)
 as task_dealloc
 from sys.dm_db_task_space_usage group by session_id) as t2
 where t1.session_id = t2.session_id
   and t2.session_id >50
 order by allocated DESC
go