Formal SQL Tuning for Oracle Databases Practical Efficiency - Effici
The target of SQL tuning is the improvement of the existing execution plan. The authors discuss the removal of brakes in the execution plan. Such "brakes" or bottlenecks can be recognized by a formal analysis of the execution plan. For t
- PDF / 9,102,990 Bytes
- 121 Pages / 439.42 x 683.15 pts Page_size
- 92 Downloads / 271 Views
ormal SQL Tuning for Oracle Databases Practical Efficiency - Efficient Practice
Formal SQL Tuning for Oracle Databases
ThiS is a FM Blank Page
Leonid Nossov • Hanno Ernst • Victor Chupis
Formal SQL Tuning for Oracle Databases Practical Efficiency - Efficient Practice
Leonid Nossov ORACLE Deutschland B.V. & Co. KG M€unchen, Germany
Hanno Ernst T-SYSTEMS INTERNATIONAL GMBH Bamberg, Germany
Victor Chupis Vodafone GmbH D€usseldorf, Germany Translation from the German language edition “Formales SQL-Tuning f€ ur OracleDatenbanken”. # Springer-Verlag 2016. Translated from the German by Jane Scorah and David Thackray. Graphical Illustrations by Anna Nosova.
ISBN 978-3-662-50416-1 ISBN 978-3-662-50417-8 DOI 10.1007/978-3-662-50417-8
(eBook)
Library of Congress Control Number: 2016950905 # Springer-Verlag Berlin Heidelberg 2016 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. Printed on acid-free paper This Springer imprint is published by Springer Nature The registered company is Springer-Verlag GmbH Berlin Heidelberg
I know that I know nothing Socrates
ThiS is a FM Blank Page
Foreword by Watson
The mantra I chant relentlessly is “you must understand your data; you must understand your queries.” By this I mean that if a developer has a complete understanding of the information he is processing, he will be able to write code that will run efficiently. The critical decisions that Oracle’s cost-based optimizer must make are join order, join method, and access method. Use of structures such as DISTINCT to remove duplicates when none exist, or OUTER JOIN when INNER JOIN will do, or needless functions around predicate columns, or inappropriate use of NULL will force the CBO to develop plans that do not make the best decisions and therefore cripple performance. There are more complex issues such as whether views are mergeable or predicate pushable, whether correlated subqueries can be factored out into common table expressions—any number of other optimizations. The CBO (co
Data Loading...
