July 8, 2008 at 7:25 am
INDEX ON TABLES
HI ALL,
Can anyone tell me how to decide which table to index and which not to index..
both cases plss..most important is when should we not INDEX a column..
Why is it HArmful to INDEX???
Thanks in advance
Thanks [/font]
July 8, 2008 at 7:39 am
Index placement depends on what queries you have running and what your data distribution looks like. To put it very simply, you create indexes to support queries that you have running.
Don't index columns that are never filtered on or joined on. It's a waste of space and it slows down data changes.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
July 8, 2008 at 7:41 am
Thanks
Thanks [/font]
July 9, 2008 at 10:47 am
Hi
Indexes cannot be created in a vacuum. In other words, before you can identify and create optimal indexes for your tables, you must thoroughly understand the kinds of queries that will be run against them. This is not an easy task, especially if you are attempting to add indexes to a new database.
Whether you are optimizing the indexes for the first time for a new database, or for a current production database, you need to identify what queries are run, and how often they are run. Obviously, you will want to spend more time creating and tuning indexes for queries that are run very often than for queries that are seldom run. In addition, you will want to identify those queries that are the most resource intensive, even if they aren't run the most often.
Once you know which queries run the most often, and which are the most resource intensive, you can begin to better allocate your time in order to get the biggest bang for your time invested.
Check out the below link
http://www.sql-server-performance.com/tips/index_main.aspx
Thanks -- Vj
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