need one doubt clarification application team trying to execute a simple query

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need one doubt clarification application team trying to execute a simple query

naga.rohitkumar

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November 22, 2012 at 10:29 pm

#266322

hi all
need one doubt clarification
application team trying to execute a simple query
but its taking long time
i tried evry thing
suppose if we rebuild the indexes of the table in a database which the query is using !
wiill it be any impact on the production server performance
or after rebuilding the table wheter we have to rearrrange the colums of the table which previous ly having
?
can we rebuild the index if we do so will it increase performance of the query
Thanks
Naga.Rohitkumar

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Orlando Colamatteo SSC Guru Points: 182279 More actions · Answer 1

You are not providing nearly enough info to enable us to effectively help you. Post the slow query, all table definitons (including indexes) for tables involved in the query and the actual execution plan for the query.

Please read this article:

How to Post Performance Problems By Gail Shaw[/url]

There are no special teachers of virtue, because virtue is taught by the whole community.
--Plato

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 2

naga.rohitkumar (11/22/2012)
or after rebuilding the table wheter we have to rearrrange the colums of the table which previous ly having

Order of columns in a table has no meaning.

can we rebuild the index if we do so will it increase performance of the query

Probably not. To make a query run faster, tune the query. May involve rewriting the query, may involve indexes.

Chapters 3, 6 and 7 http://www.simple-talk.com/books/sql-books/troubleshooting-sql-server-a-guide-for-the-accidental-dba/

and

http://www.simple-talk.com/sql/performance/finding-the-causes-of-poor-performance-in-sql-server,-part-1/

http://www.simple-talk.com/sql/performance/finding-the-causes-of-poor-performance-in-sql-server,-part-2/

(both of which I have referred you to before)

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

naga.rohitkumar SSCertifiable Points: 5738 More actions · Answer 3

this is the query

select count(*) from acmt

when we execute this output has to display the records count in it

but some times it is taking 12 to 20 mins also actuall execution time is 2 to 10 secs

Thanks
Naga.Rohitkumar

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 4

Please read Opc's post.

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

naga.rohitkumar SSCertifiable Points: 5738 More actions · Answer 5

select count(*) from acmt

1. if the query is getting slow to execute what should we check in activity monitor other than spid !

2. can we trace any thing in the activity monitor lock by object if so what is it?

Thanks
Naga.Rohitkumar

Orlando Colamatteo SSC Guru Points: 182279 More actions · Answer 6

It could be any number of things but from the information you provided so far it sounds like you may be experiencing intermittent blocking. Select count(*) with no where-clause means the entire table will require a scan. There's really no way to make that go faster. If anything else is running that has an exclusive lock on any part of the table needed by the scan then the count(*) query will be forced to wait.

INF: Understanding and resolving SQL Server blocking problems

How many rows are in the table? Start looking at what else is going on in the database when the query starts taking a long time. Forget Activity Monitor. Start getting familiar with the DMVs

From SQL Server: Transaction Management

-- Look for blocking

SELECT tl.resource_type , tl.resource_database_id , tl.resource_associated_entity_id , tl.request_mode , tl.request_session_id , wt.blocking_session_id , wt.wait_type , wt.wait_duration_ms

FROM sys.dm_tran_locks AS tl INNER JOIN sys.dm_os_waiting_tasks AS wt ON tl.lock_owner_address = wt.resource_address

ORDER BY wait_duration_ms DESC ;

There are no special teachers of virtue, because virtue is taught by the whole community.
--Plato

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 7

opc.three (11/27/2012)
Select count(*) with no where-clause means the entire table will require a scan.

It's a view, not a table (stated as such in a different thread).

Naga, as Opc stated earlier, we need more information (not the same info posted again). The view definition, the table definitions, the index definitions, the execution plan.

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

naga.rohitkumar SSCertifiable Points: 5738 More actions · Answer 8

here by the below execution plan states that it is going for full table scan and taking 79% of table and first table is taking 117mb nearly and second table is taking the 600mb nearly and it is a having indexes properly in both the tables

Thanks
Naga.Rohitkumar

Bhuvnesh SSC Guru Points: 59351 More actions · Answer 9

naga.rohitkumar (12/3/2012)
it is a having indexes properly in both the tables

NO use of here as both the tables are going for table scan plus parallelism too for puling out heavy data. can you post the related query too ?

-------Bhuvnesh----------
I work only to learn Sql Server...though my company pays me for getting their stuff done;-)

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 10

Not a picture of the exec plan, which is fairly useless. The execution plan saved to a file. Plus the view definition, the table definitions, the index definitions.

Please read the article that Opc posted in his first reply on this thread.

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

naga.rohitkumar SSCertifiable Points: 5738 More actions · Answer 11

the query is also in the execution plan out put and application team frequently check

this simple query to check the count ---->> select count(*) from acmt

Thanks
Naga.Rohitkumar

Ant-Green SSC Guru Points: 113507 More actions · Answer 12

We need the execution plan as a SQLPLAN file.

We also need the CREATE VIEW definition

We also need the CREATE TABLE definition of all the tables in the query and or view

We also need all the CREATE INDEX definitions of all the indexes on all the tables in the query

We also need the FULL SQL STATEMENT used when generating the execution plan.

Please follow the links in my signature, on posting performance problems and how to post code and data. Without this we cannot help you further.

Remember we cannot see what you can see.