Sample stored procedure that lists rarely-used indexes. Because the number and type of accesses are tracked in dmvs, this procedure can find indexes that are rarely useful. Because the cost of these indexes is incurred during maintenance (e.g. insert, update, and delete operations), the write costs of rarely-used indexes may outweigh the benefits. This stored procedure requires Microsoft SQL Server 2005.
Script Code
declare @dbid int
select @dbid = db_id()
select objectname=object_name(s.object_id), s.object_id
, indexname=i.name, i.index_id
, user_seeks, user_scans, user_lookups, user_updates
from sys.dm_db_index_usage_stats s,
sys.indexes i
where database_id = @dbid
and objectproperty(s.object_id,'IsUserTable') = 1
and i.object_id = s.object_id
and i.index_id = s.index_id
order by (user_seeks + user_scans + user_lookups + user_updates) asc
Performance of the SQL MERGE vs. INSERT/UPDATE
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MERGE is designed to apply both UPDATE and INSERTs into a target table from
a source table. The statement can do both at once, or simply do INSERTs or
on...
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