SQL SERVER – Missing Index Script – Download

Performance Tuning is quite interesting and Index plays a vital role in it. A proper index can improve the performance and a bad index can hamper the performance. In this blog post we will discuss about Missing Index. Here is the script from my script bank, which I use to identify missing indexes on any database.

Please note, if you should not create all the missing indexes this script suggest. This is just for guidance. You should not create more than 5-10 indexes per table. Additionally, this script sometime does not give accurate information so use your common sense.

Anyway, the scripts is a good starting point. You should pay attention to Avg_Estimated_Impact when you are going to create an index. The index creation script is also provided in the last column.

-- Missing Index Script
-- Original Author: Pinal Dave 
SELECT TOP 25
dm_mid.database_id AS DatabaseID,
dm_migs.avg_user_impact*(dm_migs.user_seeks+dm_migs.user_scans) Avg_Estimated_Impact,
dm_migs.last_user_seek AS Last_User_Seek,
OBJECT_NAME(dm_mid.OBJECT_ID,dm_mid.database_id) AS [TableName],
'CREATE INDEX [IX_' + OBJECT_NAME(dm_mid.OBJECT_ID,dm_mid.database_id) + '_'
+ REPLACE(REPLACE(REPLACE(ISNULL(dm_mid.equality_columns,''),', ','_'),'[',''),']','') 
+ CASE
WHEN dm_mid.equality_columns IS NOT NULL 
AND dm_mid.inequality_columns IS NOT NULL THEN '_'
ELSE ''
END
+ REPLACE(REPLACE(REPLACE(ISNULL(dm_mid.inequality_columns,''),', ','_'),'[',''),']','')
+ ']'
+ ' ON ' + dm_mid.statement
+ ' (' + ISNULL (dm_mid.equality_columns,'')
+ CASE WHEN dm_mid.equality_columns IS NOT NULL AND dm_mid.inequality_columns 
IS NOT NULL THEN ',' ELSE
'' END
+ ISNULL (dm_mid.inequality_columns, '')
+ ')'
+ ISNULL (' INCLUDE (' + dm_mid.included_columns + ')', '') AS Create_Statement
FROM sys.dm_db_missing_index_groups dm_mig
INNER JOIN sys.dm_db_missing_index_group_stats dm_migs
ON dm_migs.group_handle = dm_mig.index_group_handle
INNER JOIN sys.dm_db_missing_index_details dm_mid
ON dm_mig.index_handle = dm_mid.index_handle
WHERE dm_mid.database_ID = DB_ID()
ORDER BY Avg_Estimated_Impact DESC
GO

If you need further help with this script, do leave a comment or send me email at my email address.

Note: It goes without saying, please test all the script on your development server and after they pass your test, deploy them on production server.

Reference: Pinal Dave (https://blog.sqlauthority.com)

SQL Download, SQL Index, SQL Scripts, SQL Server
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85 Comments. Leave new

  • Husain Sanwerwala
    September 3, 2020 1:37 pm

    Hi Pinal
    How to get query detail or script that generate missing index record.

    Reply
  • Hi Pinal,
    I have an installation of SQL Server 2008 R2 (one of a few) and it’s reasonably busy system. I’m trying to optimise some of the indexes by using information from missing indexes tables.

    What seems to be strange is that sys.dm_db_missing_index_group_stats table is empty?!

    Reply
  • awesome dave, thanks!

    Reply

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