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Is it really unused index?


Is it really unused index?

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SQL Galaxy
SQL Galaxy
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Hi,

Can you confirm, Is it really unused index?

UserSeek - 16951
UserScans - 11803
UserLookup- 0
UserUpdates - 62992

rgds
ananda
GilaMonster
GilaMonster
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Since there's a non-zero number of seeks and scans, no that is not unused (it's been used for seeks and scans)

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

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SQL Galaxy
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Thanks for reply.. some of the index result showing as below, it is treated as used index?

Index A

UserSeek - 193121
UserScans - 0
UserLookup- 0
UserUpdates - 49183

Index B

UserSeek - 0
UserScans - 0
UserLookup- 0
UserUpdates - 128920
Seraj Alam-256815
Seraj Alam-256815
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Hi,

Index A is indeed in use as Gila suggested earlier.
Index B not being used for query, but it may be important if it is clustered index or Primary Key.
I use below query to evaluate how usefull is my index.

SELECT OBJECT_NAME(s.[object_id]) AS [Table Name], i.name AS [Index Name], i.index_id,
user_updates AS [Total Writes], user_seeks + user_scans + user_lookups AS [Total Reads],
user_updates - (user_seeks + user_scans + user_lookups) AS [Difference]
FROM sys.dm_db_index_usage_stats AS s WITH (NOLOCK)
INNER JOIN sys.indexes AS i WITH (NOLOCK)
ON s.[object_id] = i.[object_id]
AND i.index_id = s.index_id
WHERE OBJECTPROPERTY(s.[object_id],'IsUserTable') = 1
AND s.database_id = DB_ID()
AND user_updates > (user_seeks + user_scans + user_lookups)
AND i.index_id > 1
ORDER BY [Difference] DESC, [Total Writes] DESC, [Total Reads] ASC;
GilaMonster
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Bear in mind that those views are only since the last time SQL was started, not all time.

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


Evgeny
 Evgeny
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Also, be aware that some indexes exists for maintain constraints - unique indexes. And it could looks like unused...
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