Thought I’d share something I threw together for a client today. They were looking for index a list of indexes in a database with their associated sizes and usage.
SELECT object_name(i.object_id) as table_name ,COALESCE(i.name, space(0)) as index_name ,ps.partition_number ,ps.row_count ,Cast((ps.reserved_page_count * 8)/1024. as decimal(12,2)) as size_in_mb ,COALESCE(ius.user_seeks,0) as user_seeks ,COALESCE(ius.user_scans,0) as user_scans ,COALESCE(ius.user_lookups,0) as user_lookups ,i.type_desc FROM sys.all_objects t INNER JOIN sys.indexes i ON t.object_id = i.object_id INNER JOIN sys.dm_db_partition_stats ps ON i.object_id = ps.object_id ANDi.index_id = ps.index_id LEFT OUTER JOIN sys.dm_db_index_usage_stats ius ON ius.database_id = db_id() ANDi.object_id = ius.object_id AND i.index_id = ius.index_id ORDER BY object_name(i.object_id), i.name
Using this WHERE statement allowed them to identify 38GB of index space that was being allocated unnecessarily for indexes.
WHERE i.type_desc NOT IN ('HEAP', 'CLUSTERED') AND i.is_unique = 0 AND i.is_primary_key = 0 AND i.is_unique_constraint = 0 AND COALESCE(ius.user_seeks,0) <= 0 AND COALESCE(ius.user_scans,0) <= 0 AND COALESCE(ius.user_lookups,0) <= 0
As with most DMVs these stats are accumulated since the last server start. This should just give a good starting point for finding unnecessary indexes and determining by their size if dropping the index would have a significant impact on database space. It would not be advisable to do a bit more research before taking any action.
Also, I ran the following query and got some interesting results.
select * from users where clue > 0 (0 row(s) affected)
OK, I saw it on a shirt… Hehe…