Updated Unused Index Query

January 13, 2009 · Posted in SQL Server 

I have cleaned up and updated my unused index query. It returns a list of indexes ordered by ascending reads. If the instance has been up for a long time, it is probably safe to drop indexes with zero or close to zero reads. If the reads are low and the writes are high, this may help improve your transactions per second count. Otherwise, you are just cleaning up unused space. Use caution though. A missing index is worse than an unused index.

SELECT objectname=OBJECT_NAME(s.OBJECT_ID)
,
indexname=i.name
, i.index_id  
, reads=user_seeks + user_scans + user_lookups  
, writes user_updates  
, p.rows
FROM sys.dm_db_index_usage_stats s JOIN sys.indexes i 
ON i.index_id = s.index_id AND s.OBJECT_ID = i.OBJECT_ID  
JOIN sys.partitions p ON p.index_id = s.index_id AND s.OBJECT_ID = p.OBJECT_ID
WHERE OBJECTPROPERTY(s.OBJECT_ID,'IsUserTable') = 1  
AND s.database_id = DB_ID()  
AND
i.type_desc = 'nonclustered'
AND i.is_primary_key = 0
AND i.is_unique_constraint = 0
AND p.rows > 10000
ORDER BY reads, rows DESC

I will also be putting this query up at the SSP WIKI.

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