Fragmentation and Database Performance in Sybase
_{A technical white paper by White Sands Technology, Inc.}
Copyright : white sand technologies inc
http://www.whitesands.com

Table of Contents
Preface............................................................................................1
Introduction....................................................................................1
Why Be Concerned With Fragmentation?...................................................1
What is Fragmentation?................................................................2
Definition of Terms ........................................................................................2
Fragmentation Defined..................................................................................3
Types of Fragmentation ................................................................4
Messy Page Chains .......................................................................................4
Poor Page Utilization .....................................................................................6
Extent Fragmentation ....................................................................................8
Row Fragmentation .......................................................................................9
Dealing With Fragmentation .........................................................9
Analyzing Effects of Deletes.......................................................................10
Analyzing Effects of Inserts........................................................................10
Analyzing Effects of Updates .....................................................................11
Preventing Extent Fragmentation ..............................................................12
Capacity Planning for Defragmentation ....................................................12
Use Fixed-Length Row Sizes......................................................................14
Use Monotonically-Increasing Clustered Index Keys ..............................14
Use Unique Clustered Index Keys .............................................................15
Large I/O Considerations ............................................................................15
The Big Picture ............................................................................16
Conclusion ...................................................................................17


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