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An
Introduction to
Sybase
® Adaptive Server ® Enterprise’s
Modern Optimizer
A
Collection of Articles Reprinted from ISUG Technical Journal
Table
of Contents
Introduction
Introduction to Abstract Query Plans in ASE 12.0
Where, Why and How To Add or Modify Optimizer Statistics
Optimizer Mythology and Folklore (and Some FAQs)
Using Optdiag Simulate In ‘What-If’ Analysis
An Introduction to Utilizing Optdiag Output
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Introduction
Interest among
users about how the ASE optimizer works, and how to work with it has grown considerably
in recent years. Performance in general, and optimization in particular are
quickly becoming "the last frontier" of the RDBMS.
Recent version
s of ASE have brought a great deal of change in the realm of optimization. The
five articles in this collection all deal with various aspects of these changes.
Some of them give you detailed information on how to take advantage of new functionality
in the optimizer while one of them dispels old folklore about the optimizer.
"An Introduction
to Utilizing Optdiag Output" – This article describes how to read and understand
the output of the optdiag utility. This utility allows you to read, write and
simulate the statistics used by the optimizer to determine the most efficient
method to retrieve the required data. In "Using Optdiag Simulate in 'What-If'
Analysis" you’ll find information on how to use Optdiag’s simulate mode to simulate
changes to you data and perform a ‘what-if’ analysis .
"Where, Why and
How to Add or Modify Optimizer Statistics" give you tips and tricks on how you
can add and/or change the optimizer statistics in order to give the optimizer
the most accurate information possible about your data.
"An Introduction
to Abstract Query Plans in ASE 12.0" introduces a new feature of ASE 12.0, Abstract
Plans. This feature allows you run a query, capture and save the query plan
created by the optimizer and then reuse it whenever the same query is run again.
You can edit an Abstract Plan, thus telling the optimizer exactly what to do,
or simply use it as is. This is a very powerful and flexible feature.
The final article,
"Optimizer Mythology and Folklore (and Some FAQs)" dispels some old optimizer
related myths and folklore. The more correct information you have about how
the optimizer works the easier your tuning jobs will be. There are also some
frequently asked optimizer questions.
I hope you find
these articles informative and useful in your work with ASE.
Eric Miner
Sr. Engineer
Sybase, Inc.
DST Engineering
Optimizer Group
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