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SQL Server Tips by Burleson |
Unused Indexes
To begin with, it is imperative to know which indexes are not being
used for a number of reasons. Indexes take up space, so unused
indexes waste storage. Indexes also require maintenance for each DML
statement, so there is a performance penalty on tables with many
indexes that experience high INSERT, UPDATE and DELETE activity.
With new designs, the DBA may not know what indexes will be used, so
the basic standard indexing scheme of primary key indexes, clustered
indexes, and indexes on most foreign key columns will need to be
performed. If load testing scenarios can be implemented before the
first day of production, it could be possible to weed out unused
indexes.
So, how can unused indexes be located? The DBA can try the Index
Tuning Wizard in SQL Server 7 – 2000 or the Database Tuning Advisor
in SQL Server 2005. There are also third party products on the
market that will capture and analyze SQL workflow and report on
unused indexes. Ambeo is currently one such company.
The above book excerpt is from:
High-Performance SQL Server DBA
Tuning & Optimization Secrets
ISBN:
0-9761573-6-5
Robin Schumacher
http://www.rampant-books.com/book_2005_2_sql_server_dba.htm |
