Level: Intermediate Mark Baldridge (mbaldrid@us.ibm.com), Principal Consultant, North American Lab Services, IBM
24 Jan 2008
This installment of the UniVerse®
performance series, investigates the effects of field-level caching in dynamic array access and suggests improvements for dynamic array access.
Objectives - Contrast processing dynamic arrays at the value and field levels.
- Explore the cost of different methods of converting between dynamic arrays of values and fields.
Prerequisites
You should have a familiarity with writing and compiling UniVerse BASIC programs.
System requirements
This tutorial requires an installation of UniVerse. You can download a Personal
Edition of UniVerse for Red Hat Linux® or Microsoft Windows®
from the
IBM® Web site.
The personal edition has file size restrictions that prohibit some tests, such as test 1332, which creates a 1GB file.
Duration
Formats html, pdf
Tutorial overview
This series of tutorials provides the UniVerse DBA and application designers with tools for making reasoned and metrically-justified decisions about choices in everyday tasks. The subject matter of this series of articles and tutorials on UniVerse performance tuning arises from visits to customer sites. The issues raised do not disparage the customer, but reflect a real-world predicament. The typical developer or DBA has so many outstanding tasks that by the time one task is complete, at least one more has joined those remaining. They all demand attention. Sufficient time exists to make something work, but typically not enough to make it work well.
This installment explores the effects of field caching in dynamic arrays. It starts by examining the dynamic array, and explores historical background on why code frequently processes dynamic array values in lieu of dynamic array fields. It then explores techniques for processing dynamic array values at the field level.
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