March 2012
Intermediate to advanced
442 pages
9h 31m
English
Content preview from IBM DB2 9.7 Advanced Application Developer CookbookBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Using optimizer profiles
DB2 uses cost-based optimization for choosing the access plan for a query. The total cost depends on various factors, such as system configuration, database and database manager configuration, memory available (buffer pool, sort heap, and so on), current optimization level, CPU parallelism, IO characteristics, and so on, and most importantly information regarding the actual data. In the DB2 terminology, this is also known as catalog statistics. Therefore, it is always recommended to keep the statistics updated. These statistics include information about the following:
- Number of rows, data pages, active blocks, data range information, data length, and so on
- Most frequent values
- Number of distinct values for a column, and ...
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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.
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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.