Users: 15,000+ | Page Views: 50,000+ | PPS: 2.5
TechDevOps.com
Explore Tools
{Experts in Microsoft SQL Server Operations, Performance, HA/DR, Data Migrations & Cloud Computing}



T-SQL - Find Missing Indexes - incl. Improvement Measure and Avg User Impact
by BF (Senior MSSQL Operations - Enterprise, Cloud, Strategy)
2017-11-08









T-SQL:

SELECT CONVERT (varchar, getdate(), 126) AS runtime,
mig.index_group_handle, mid.index_handle,
CONVERT (decimal (28,1), migs.avg_total_user_cost * migs.avg_user_impact * (migs.user_seeks + migs.user_scans)) AS improvement_measure,
'CREATE INDEX missing_index_' + CONVERT (varchar, mig.index_group_handle) + '_' + CONVERT (varchar, mid.index_handle)
+ ' 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 CONVERT (decimal (28,1), migs.avg_total_user_cost * migs.avg_user_impact * (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


Improvement_Measure > 1,000,000 and Avg_User_Impact > 80, usually good to add the index.