Karthick P.K on SQL Server

Archive for January, 2010

Script to clear stats

Posted by Karthick P.K on January 20, 2010

How to reset SQL Server stats with out restarting.

DBCC SQLPERF ('spinlockstats', CLEAR);




DBCC SQLPERF ('netstats', CLEAR);




DBCC SQLPERF ('rastats', CLEAR);




DBCC SQLPERF ('iostats', CLEAR);




DBCC SQLPERF ('threads', CLEAR);




DBCC SQLPERF ('logspace', CLEAR);




DBCC SQLPERF ('umsstats', CLEAR);




DBCC SQLPERF ('waitstats', CLEAR);



Posted in Performance, SQL General, SQL Query | Tagged: | 2 Comments »

Monitoring Tempdb usage

Posted by Karthick P.K on January 13, 2010

Monitoring Tempdb space usage and identifying the session and query which Consumes Tempdb

The total space used by Tempdb consists of 

1. User Objects 

2.  Internal Objects

3. Version Store

4. Free Space.

Use  Below Query to Track which objects (above) is consuming pace in TempDb. 


SUM(unallocated_extent_page_count) AS [free pages], (SUM(unallocated_extent_page_count)*1.0/128) AS [free space in MB],SUM(version_store_reserved_page_count) AS [version store pages used],

(SUM(version_store_reserved_page_count)*1.0/128) AS [version store space in MB],SUM(internal_object_reserved_page_count) AS [internal object pages used],

(SUM(internal_object_reserved_page_count)*1.0/128) AS [internal object space in [MB],SUM(user_object_reserved_page_count) AS [user object pages used],

(SUM(user_object_reserved_page_count)*1.0/128) AS [user object space in MB]

FROM sys.dm_db_file_space_usage;


Once you have identified the objects identify the query and session which is consuming tempdb using the query listed below

–Use below query to identify which Query and Session is consuming the space in TempDB

SELECT R1.session_id, R1.request_id, R1.Task_request_internal_objects_alloc_page_count, R1.Task_request_internal_objects_dealloc_page_count,

R1.Task_request_user_objects_alloc_page_count,R1.Task_request_user_objects_dealloc_page_count,R3.Session_request_internal_objects_alloc_page_count ,


R2.sql_handle, RL2.text as SQLText, R2.statement_start_offset, R2.statement_end_offset, R2.plan_handle FROM (SELECT session_id, request_id, 

SUM(internal_objects_alloc_page_count) AS Task_request_internal_objects_alloc_page_count, SUM(internal_objects_dealloc_page_count)AS 

Task_request_internal_objects_dealloc_page_count,SUM(user_objects_alloc_page_count) AS Task_request_user_objects_alloc_page_count,

SUM(user_objects_dealloc_page_count)AS Task_request_user_objects_dealloc_page_count FROM sys.dm_db_task_space_usage 

GROUP BY session_id, request_id) R1 INNER JOIN (SELECT session_id, SUM(internal_objects_alloc_page_count) AS Session_request_internal_objects_alloc_page_count,

SUM(internal_objects_dealloc_page_count)AS Session_request_internal_objects_dealloc_page_count,SUM(user_objects_alloc_page_count) AS Session_request_user_objects_alloc_page_count,

SUM(user_objects_dealloc_page_count)AS Session_request_user_objects_dealloc_page_count FROM sys.dm_db_Session_space_usage 

GROUP BY session_id) R3 on R1.session_id = R3.session_id 

left outer JOIN sys.dm_exec_requests R2 ON R1.session_id = R2.session_id and R1.request_id = R2.request_id

OUTER APPLY sys.dm_exec_sql_text(R2.sql_handle) AS RL2
Task_request_internal_objects_alloc_page_count >0 or  
Task_request_internal_objects_dealloc_page_count>0 or 
Task_request_user_objects_alloc_page_count >0 or 
Task_request_user_objects_dealloc_page_count >0 or 
Session_request_internal_objects_alloc_page_count >0 or 
Session_request_internal_objects_dealloc_page_count >0 or 
Session_request_user_objects_alloc_page_count >0 or 
Session_request_user_objects_dealloc_page_count >0 

Known issues related to TEMPDB Shrink

FIX: The used space in the tempdb database increases continuously when you run a query that creates internal objects in the tempdb database in SQL Server 2005

Thank you,

Karthick P.K | My Facebook Page |My Site| Blog space| Twitter

Posted in Performance, SQL General, SQL Query | Tagged: , , , , , , , , , , | 4 Comments »

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