Wednesday, September 17, 2014

Missing Indices in SQL Server

Run the following to show possible missing indices in SQL Server.  Use this information carefully!!!  Do your own evaluation to determine if you really need any of the indices this suggests.  This is only a recommendation.

 SELECT  
 mid.statement  
  ,migs.avg_total_user_cost * (migs.avg_user_impact / 100.0) * (migs.user_seeks + migs.user_scans) AS improvement_measure,OBJECT_NAME(mid.Object_id),  
  'CREATE INDEX [missing_index_' + CONVERT (VARCHAR, mig.index_group_handle) + '_' + CONVERT (VARCHAR, mid.index_handle)  
  + '_' + LEFT (PARSENAME(mid.statement, 1), 32) + ']'  
  + ' ON ' + mid.statement  
  + ' (' + ISNULL (mid.equality_columns,'')  
   + CASE WHEN mid.equality_columns IS NOT NULL AND mid.inequality_columns IS NOT NULL THEN ',' ELSE '' END  
   + ISNULL (mid.inequality_columns, '')  
  + ')'  
  + ISNULL (' INCLUDE (' + mid.included_columns + ')', '') AS create_index_statement,  
  migs.*, mid.database_id, mid.[object_id]  
 FROM sys.dm_db_missing_index_groups mig  
 INNER JOIN sys.dm_db_missing_index_group_stats migs ON migs.group_handle = mig.index_group_handle  
 INNER JOIN sys.dm_db_missing_index_details mid ON mig.index_handle = mid.index_handle  
 WHERE migs.avg_total_user_cost * (migs.avg_user_impact / 100.0) * (migs.user_seeks + migs.user_scans) > 10  
 ORDER BY migs.avg_total_user_cost * migs.avg_user_impact * (migs.user_seeks + migs.user_scans) DESC  

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