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Markus
Markus
SSCommitted
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Group: General Forum Members
Points: 1820 Visits: 3728
Funny that I just saw this article. We JUST tackled this exact situation in a large SS database last week. Good article ! I wish i would have had this info two weeks ago.



WHug
WHug
Valued Member
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Group: General Forum Members
Points: 63 Visits: 399

With SQL Server 2005 you also have the opportunity to Include additional columns in your index. This is in BOL at:

ms-help://MS.SQLCC.v9/MS.SQLSVR.v9.en/udb9/html/d198648d-fea5-416d-9f30-f9d4aebbf4ec.htm

"An index with included nonkey columns can significantly improve query performance when all columns in the query are included in the index either as key or nonkey columns. Performance gains are achieved because the query optimizer can locate all the column values within the index; table or clustered index data is not accessed resulting in fewer disk I/O operations."





Megha Yadav
Megha Yadav
SSC-Enthusiastic
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Group: General Forum Members
Points: 171 Visits: 162
Amazing article ....... On similar lines please find another link :: http://blogs.msdn.com/craigfr/archive/2006/06/30/652639.aspx
Anipaul
Anipaul
SSCertifiable
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Group: General Forum Members
Points: 6467 Visits: 1407
Excellent and very useful article...



Grant Fritchey
Grant Fritchey
SSCoach
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Group: General Forum Members
Points: 19458 Visits: 32324
David Tiss (7/27/2007)


Great article, I learned a lot.

I'm wondering if the included column feature in SQL Server 2005 will also help with bookmark lookups?


INCLUDE columns absolutely help with lookup issues.

----------------------------------------------------
The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood...
Theodore Roosevelt

The Scary DBA
Author of: SQL Server Query Performance Tuning and SQL Server Execution Plans
Product Evangelist for Red Gate Software
Grant Fritchey
Grant Fritchey
SSCoach
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Group: General Forum Members
Points: 19458 Visits: 32324
This is a good article. I can see why it was reprinted. I'd like to see an update. Things are just a little different in 2005/2008. Those differences, some of them cosmetic, such as the change from bookmark lookup to RID lookup in the execution plans, would change some of the details of the article as well as some of the methods of correction (INCLUDE has been mentioned several times).

----------------------------------------------------
The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood...
Theodore Roosevelt

The Scary DBA
Author of: SQL Server Query Performance Tuning and SQL Server Execution Plans
Product Evangelist for Red Gate Software
@RadM
@RadM
Grasshopper
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Group: General Forum Members
Points: 11 Visits: 32
Firstly , thank you for explaining Bookmark lookups with such clarity !

I have the same question as SSC-Enthusiastic , how many covering index can we really afford to create ?
@RadM
@RadM
Grasshopper
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Group: General Forum Members
Points: 11 Visits: 32
Hi Markus ,
Could you give us some pointers beyond this article since you
mentioned that you've just dealt with the same at a large scale

Thanks !
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