March 2009
Intermediate to advanced
562 pages
15h 36m
English
Content preview from SQL Server 2008 Query Performance Tuning Distilled
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C H A P T E R 6
Bookmark Lookup Analysis
To maximize the benefit from nonclustered indexes, you must minimize the cost of the data retrieval as much as possible. A major overhead associated with nonclustered indexes is the cost of excessive key lookups, commonly known as bookmark lookups, which are a mechanism to navigate from a nonclustered index row to the corresponding data row in the clustered index or the base table. Therefore, it makes sense to look at the cause of bookmark lookups and to evaluate how to avoid this cost.
In this chapter, I cover the following topics:
- The purpose of bookmark lookups
- Drawbacks of using bookmark lookups ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.