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ERROR || The query processor is unable to produce a plan because the index ‘IND_TABLE’ on table or view ‘Table’ is disabled.


Table with clustered index is totally depended on index accessibility.

ERROR : The query processor is unable to produce a plan because the index ‘IND_TABLE’ on table or view ‘Table’ is disabled.

REASON : We find that some disable the cluster index due to which issue occur. Clustered index physically sort & save data in pages. When clustered index is disable, DB engine is not able to access data although data is available with table.

SCREENSHOT :

Note :

· There is no option to ENABLE the Index. You have to REBUILD or DROP & RECREATE it.

· This is not the case with non-clustered index.

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Reference : Rohit Garg(http://mssqlfun.com/)

DMV-15 : Pending I/O requests……..sys.dm_io_pending_io_requests


sys.dm_io_pending_io_requests DMV (Dynamic Management View), described by BOL as follows: http://msdn.microsoft.com/en-us/library/ms188762.aspx

Returns a row for each pending I/O request in SQL Server.

It’s a very simple DMV used to see all pending I/O requests & there description.

You can combine this DMV with DMF – sys.dm_io_virtual_file_stats to see I/O pending requests with database files. You should run this query multiple times to check if the same files or drive letters consistently coming up on the top. If this is the case that means you facing I/O bottlenecks for that file or drive letter.

Query 1 : Details of I/O pending requests against each DB file

SELECT

DB_NAME(MF.DATABASE_ID) AS [DATABASE],

MF.PHYSICAL_NAME,

IPIR.IO_TYPE,

SUM(IPIR.IO_PENDING) TOTAL_PENDING_IO,

SUM(IPIR.IO_PENDING_MS_TICKS) TOTAL_PENDING_MS_TICKS,

SUM(VFS.NUM_OF_READS) TOTAL_READS,

SUM(VFS.NUM_OF_WRITES) TOTAL_WRITES

FROM

SYS.DM_IO_PENDING_IO_REQUESTS AS IPIR

INNER JOIN

SYS.DM_IO_VIRTUAL_FILE_STATS(NULL,NULL) AS VFS

ON IPIR.IO_HANDLE = VFS.FILE_HANDLE

INNER JOIN

SYS.MASTER_FILES AS MF

ON VFS.DATABASE_ID = VFS.DATABASE_ID

AND VFS.FILE_ID = MF.FILE_ID

GROUP BY MF.DATABASE_ID, MF.PHYSICAL_NAME, IPIR.IO_TYPE

ORDER BY SUM(IPIR.IO_PENDING)

Remarks

1. To use this DMV, User required VIEW SERVER STATE permission on the server.

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Reference : Rohit Garg (http://mssqlfun.com/)

DMV-9 : Digging out details of CLR Tasks……..sys.dm_clr_tasks


sys.dm_clr_tasks DMV (Dynamic Management View), described by BOL as follows: http://msdn.microsoft.com/en-in/library/ms177528.aspx

Returns a row for all common language runtime (CLR) tasks that are currently running. A Transact-SQL batch that contains a reference to a CLR routine creates a separate task for execution of all the managed code in that batch. Multiple statements in the batch that require managed code execution use the same CLR task. The CLR task is responsible for maintaining objects and state pertaining to managed code execution, as well as the transitions between the instance of SQL Server and the common language runtime.

sys.dm_clr_tasks DMV is applicable to you if you have enabled the CLR on your SQL Server instance, and you are using at least one CLR assembly loaded in any of one user databases on your SQL Server instance.

You should look for rows having forced_yield_count column value above zero or that have a last_wait_type of SQLCLR_QUANTUM_PUNISHMENT. This will point that the task previously exceeded its allowed quantum & caused the SQL OS scheduler to intervene and reschedule it at the end of the queue. Value of Column forced_yield_count shows the number of time that this has happened.

If you noticed this, you should talk to your developer for this. This could cause issue for you SQL Server.

How to enable CLR?

EXEC SP_CONFIGURE ‘CLR ENABLED’,1

GO

RECONFIGURE

GO

How to disable CLR?

EXEC SP_CONFIGURE ‘CLR ENABLED’,0

GO

RECONFIGURE

GO

Query 1 : FIND LONG RUNNING SQL/CLR TASKS

SELECT

OS.TASK_ADDRESS,

OS.[STATE],

OS.LAST_WAIT_TYPE,

CLR.[STATE],

CLR.FORCED_YIELD_COUNT

FROM SYS.DM_OS_WORKERS AS OS

INNER JOIN SYS.DM_CLR_TASKS AS CLR

ON (OS.TASK_ADDRESS = CLR.SOS_TASK_ADDRESS)

WHERE CLR.[TYPE] = ‘E_TYPE_USER';

Remarks

1. To use this DMV, User required VIEW SERVER STATE permission on the server.

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Reference : Rohit Garg (http://mssqlfun.com/)

Cumulative Update – 12 for SQL Server 2008 R2 Service Pack 1 Is Now Available !


The 12th cumulative update release for SQL Server 2008 R2 Service Pack 1 is now available for download at the Microsoft Support site. Cumulative Update 12 contains all the hotfixes released since the initial release of SQL Server 2008 R2 SP1.

 

 

Those who are facing severe issues with their environment, they can plan to test CU12 in test environment & then move to Production after satisfactory results.

For CU12 of SQL Server 2008 R2 SP1

· CU#12 KB Article: http://support.microsoft.com/kb/2828727

Previous Cumulative Update KB Articles:

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Reference : Rohit Garg (http://mssqlfun.com/)

DMV-7 : Find Queries waiting for memory ?……..sys.dm_exec_query_memory_grants


sys.dm_exec_query_memory_grants DMV (Dynamic Management View), described by BOL as follows : http://msdn.microsoft.com/en-IN/library/ms365393.aspx

Returns information about the queries that have acquired a memory grant or that still require a memory grant to execute. Queries that do not have to wait on a memory grant will not appear in this view.

This DMV helps in finding queries that are waiting (or recently had to wait) for a memory grant. This particular DMV works with SQL Server 2005, 2008, and 2008 R2. There were some new columns added for SQL Server 2008 and above.

You should periodically run this query multiple times in regular intervals and need to look for rows returned each time. If you do see a lot of rows returned each time, then it could be an indication of internal memory pressure. It will help you to identify queries that are requesting relatively large memory grants, perhaps because they are poorly written or they’re missing indexes that make the query more expensive.

Query 1 : Details of queries required memory to execute

SELECT DB_NAME(ST.DBID) AS [DATABASENAME],

MG.REQUESTED_MEMORY_KB ,

MG.IDEAL_MEMORY_KB ,

MG.REQUEST_TIME ,

MG.GRANT_TIME ,

MG.QUERY_COST ,

MG.DOP ,

ST.[TEXT],

QP.QUERY_PLAN

FROM SYS.DM_EXEC_QUERY_MEMORY_GRANTS AS MG

CROSS APPLY SYS.DM_EXEC_SQL_TEXT(PLAN_HANDLE) AS ST

CROSS APPLY SYS.DM_EXEC_QUERY_PLAN(MG.PLAN_HANDLE) AS QP

ORDER BY MG.REQUESTED_MEMORY_KB DESC ;

Remarks

1. User required VIEW SERVER STATE permission on the server.

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Reference : Rohit Garg (http://mssqlfun.com/)

DMV-6 : How well my store procedure doing ?……..sys.dm_exec_procedure_stats


sys.dm_exec_procedure_stats DMV (Dynamic Management View), described by BOL as follows : http://msdn.microsoft.com/en-us/library/cc280701.aspx

Returns aggregate performance statistics for cached stored procedures. The view con­tains one row per stored procedure, and the lifetime of the row is as long as the stored procedure remains cached. When a stored procedure is removed from the cache, the cor­responding row is eliminated from this view. At that time, a Performance Statistics SQL trace event is raised similar to sys.dm_exec_query_stats.

This DMV is new to SQL Server 2008 so you can use it only in SQL Server 2008 onwards. You can get similar data out of sys.dm_exec_cached_plans, which will work on SQL Server 2005. This DMV allows you to discover a lot of very interesting and important performance information about your cached stored procedures.

Query 1 : Details of cached procedures

SELECT CASE WHEN DATABASE_ID = 32767 THEN ‘RESOURCE’ ELSE DB_NAME(DATABASE_ID)END AS DBNAME

,OBJECT_SCHEMA_NAME(OBJECT_ID,DATABASE_ID) AS [SCHEMA_NAME]

,OBJECT_NAME(OBJECT_ID,DATABASE_ID)AS [OBJECT_NAME]

,*

FROM SYS.DM_EXEC_PROCEDURE_STATS

Query 2 : Details of procedure with total & average CPU, logical reads , logical writes & physical reads

SELECT CASE WHEN DATABASE_ID = 32767 THEN ‘RESOURCE’ ELSE DB_NAME(DATABASE_ID)END AS DBNAME

,OBJECT_SCHEMA_NAME(OBJECT_ID,DATABASE_ID) AS [SCHEMA_NAME]

,OBJECT_NAME(OBJECT_ID,DATABASE_ID)AS [OBJECT_NAME]

,CACHED_TIME

,LAST_EXECUTION_TIME

,EXECUTION_COUNT

,TOTAL_WORKER_TIME / EXECUTION_COUNT AS AVG_CPU

,TOTAL_ELAPSED_TIME / EXECUTION_COUNT AS AVG_ELAPSED

,TOTAL_LOGICAL_READS

,TOTAL_LOGICAL_READS / EXECUTION_COUNT AS AVG_LOGICAL_READS

,TOTAL_LOGICAL_WRITES

,TOTAL_LOGICAL_WRITES / EXECUTION_COUNT AS AVG_LOGICAL_WRITES

,TOTAL_PHYSICAL_READS

,TOTAL_PHYSICAL_READS / EXECUTION_COUNT AS AVG_PHYSICAL_READS

FROM SYS.DM_EXEC_PROCEDURE_STATS

ORDER BY AVG_LOGICAL_READS DESC

Remarks

1. User required VIEW SERVER STATE permission on the server.

2. This DMV will capture the details of 3 objects types :

a. SQL_STORED_PROCEDURE

b. CLR_STORED_PROCEDURE

c. EXTENDED_STORED_PROCEDURE

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Reference : Rohit Garg (http://mssqlfun.com/)

DMV-5 : Queries runing are adhoc or proc , single or multi use ?……..sys.dm_exec_cached_plans


sys.dm_exec_cached_plans DMV (Dynamic Management View), described by BOL as follows : http://msdn.microsoft.com/en-us/library/ms187404.aspx

Returns a row for each query plan that is cached by SQL Server for faster query execu­tion. You can use this dynamic management view to find cached query plans, cached query text, the amount of memory taken by cached plans, and the reuse count of the cached plans.

sys.dm_exec_cached_plans provide execution related details like no. of queries comes under adhoc or proc section. It help is understanding the query type & performance improvisation by looking into heavily running adhoc queries.

Query 1 : Memory used by cache plan of each database

SELECT

CP.CACHEOBJTYPE,

CP.OBJTYPE,

CASE WHEN ST.DBID = 32767 THEN ‘RESOURCEDB’ ELSE DB_NAME(ST.DBID) END AS DATABASE_NAME,

SUM(CASE WHEN CP.USECOUNTS <= 1 THEN 1 ELSE 0 END) AS SINGLE_USE_COUNT,

SUM(CASE WHEN CP.USECOUNTS > 1 THEN 1 ELSE 0 END) AS MULTI_USE_COUNT,

AVG(CASE WHEN CP.USECOUNTS > 1 THEN CP.USECOUNTS ELSE NULL END) AS MULTI_USE_AVG_USE_COUNT,

(SUM(CASE WHEN CP.USECOUNTS <= 1 THEN CP.SIZE_IN_BYTES ELSE 0 END) / (1024 * 1024)) AS SINGLE_USE_SIZE_IN_MBYTES,

(SUM(CASE WHEN CP.USECOUNTS > 1 THEN CP.SIZE_IN_BYTES ELSE 0 END) / (1024 * 1024)) AS MULTI_USE_SIZE_IN_MBYTES,

(SUM(CP.SIZE_IN_BYTES) / (1024 * 1024)) AS TOTAL_SIZE_IN_MBYTES

FROM

SYS.DM_EXEC_CACHED_PLANS AS CP

OUTER APPLY SYS.DM_EXEC_SQL_TEXT(CP.PLAN_HANDLE) AS ST

GROUP BY

CP.CACHEOBJTYPE,

CP.OBJTYPE,

CASE WHEN ST.DBID = 32767 THEN ‘RESOURCEDB’ ELSE DB_NAME(ST.DBID) END

ORDER BY

CP.CACHEOBJTYPE,

CP.OBJTYPE,

CASE WHEN ST.DBID = 32767 THEN ‘RESOURCEDB’ ELSE DB_NAME(ST.DBID) END

Query 2 : Find single-use, ad-hoc queries

SELECT ST.[TEXT] ,

CASE WHEN ST.DBID = 32767 THEN ‘RESOURCEDB’ ELSE DB_NAME(ST.DBID) END AS DATABASE_NAME,

CP.SIZE_IN_BYTES

FROM

SYS.DM_EXEC_CACHED_PLANS AS CP

CROSS APPLY SYS.DM_EXEC_SQL_TEXT(CP.PLAN_HANDLE) AS ST

WHERE CP.CACHEOBJTYPE = ‘COMPILED PLAN’

AND CP.OBJTYPE = ‘ADHOC’

AND CP.USECOUNTS = 1

ORDER BY CP.SIZE_IN_BYTES DESC

Remarks

1. User required VIEW SERVER STATE permission on the server.

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Reference : Rohit Garg (http://mssqlfun.com/)

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