i Oracle Performance Tuning and Optimization Oracle Performance Tuning and Optimization Edward Whalen 201 West 103rd Street Indianapolis, Indiana 46290 ® ii Oracle Performance Tuning & Optimization Publisher and President: Richard K. Swadley Acquisitions Manager: Greg Wiegand Development Manager: Dean Miller Managing Editor: Cindy Morrow Marketing Manager: Gregg Bushyeager To my father. Copyright  1996 by Sams Publishing FIRST EDITION All rights reserved. No part of this book shall be reproduced, stored in a retrieval system, or transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without written permission from the publisher. No patent liability is assumed with respect to the use of the information contained herein. Although every precaution has been taken in the preparation of this book, the publisher and author assume no responsibility for errors or omissions. Neither is any liability assumed for damages resulting from the use of the information contained herein. For information, address Sams Publishing, 201 W. 103rd St., Indianapolis, IN 46290. International Standard Book Number: 0-672-30866-X Library of Congress Catalog Card Number: 95-72345 99 98 97 96 4 3 2 1 Interpretation of the printing code: the rightmost double-digit number is the year of the book’s printing; the rightmost single-digit, the number of the book’s printing. For example, a printing code of 96-1 shows that the first printing of the book occurred in 1996. Composed in AGaramond and MCPdigital by Macmillan Computer Publishing Printed in the United States of America All terms mentioned in this book that are known to be trademarks or service marks have been appropriately capitalized. Sams Publishing cannot attest to the accuracy of this information. Use of a term in this book should not be regarded as affecting the validity of any trademark or service mark. Acquisitions Editor Rosemarie Graham Development Editors Byron Pearce Todd Bumbalough Software Development Specialist Steve Flatt Production Editor Alice Martina Smith Technical Reviewers David Kennedy Stephen Tallon Editorial Coordinator Bill Whitmer Technical Edit Coordinator Lynette Quinn Formatter Frank Sinclair Editorial Assistants Sharon Cox Andi Richter Rhonda Tinch-Mize Cover Designer Tim Amrhein Book Designer Alyssa Yesh Copy Writer Peter Fuller Production Team Supervisor Brad Chinn Production Mary Ann Abramson Georgianna Briggs Jama Carter Amy Chinn Michael Dietsch Jason Hand Sonja Hart Ayanna Lacey Clint Lahnen Paula Lowell Brian-Kent Proffitt Bobbi Satterfield Susan Van Ness Colleen Williams iii Overview Introduction xxiv PART I Introduction 1 1 Introduction to Oracle 3 2 Understanding Terms 21 3 What Is a Well-Tuned System? 31 4 Tuning Methodology 41 5 Benchmarking 51 6 Performance Monitoring Tools 73 7 Performance Engineering Starts at the Design Stage 81 PART II Tuning the Server 89 8 What Affects Oracle Server Performance? 91 9 Oracle Instance Tuning 97 10 Performance Enhancements 139 11 Tuning the Server Operating System 167 12 Operating System-Specific Tuning 177 13 System Processors 205 14 Advanced Disk I/O Concepts 213 15 Disk Arrays 225 PART III Configuring the System 243 16 OLTP System 245 17 Batch Processing System 265 18 Decision Support System 285 19 Data Warehousing System 303 20 BLOB System 323 21 The Oracle Parallel Server System 339 22 Optimal Backup and Recovery 349 23 Miscellaneous Configurations 367 PART IV Tuning SQL 391 24 What Is a Well-Tuned SQL Statement? 393 25 Using EXPLAIN PLAN and SQL Trace 403 26 Tuning SQL Statements 419 27 Using the Oracle Optimizer 437 28 Using Procedures, Functions, and Packages 449 29 Providing for Data Integrity and Triggers 461 30 Using Hints 475 31 Introducing SQL Development Tools 489 32 Miscellaneous SQL Topics 501 iv Oracle Performance Tuning & Optimization PART V Tuning the Client 513 33 What Affects Client Performance? 515 34 Tuning the Client System 525 35 Using GUI Builders 533 36 Using Middleware Products 555 PART VI Tuning the Network 563 37 What Affects Network Performance? 565 38 Tuning the Network Components 573 PART VII References 579 A Review of Tuning Guidelines 581 B Quick Reference 595 C Flowcharts 603 D Glossary 607 E Oracle Tuning Parameters 619 F Contents of the CD-ROM 645 Index 649 v Contents Introduction xxiv Part I Introduction 1 1 Introduction to Oracle 3 The Database 4 The Physical Layer 4 The Logical Layer 5 The Oracle Instance 8 The Oracle Memory Structure 8 System Global Area (SGA) 9 Program Global Area (PGA) 10 Processes 10 How Transactions Work 12 Oracle Products 13 Oracle RDBMS Products 13 Oracle Workgroup Server 15 Personal Oracle for Windows 16 Oracle Development Tools 16 Oracle Applications 17 Oracle Services 18 Summary 19 2 Understanding Terms 21 Terms 22 RDBMS Functionality 26 Checkpoint 26 Logging and Archiving 26 Business Models 27 OnLine Transaction Processing (OLTP) 27 Batch Processing 27 Decision Support 28 Data Warehousing 28 Binary Large Objects (BLOBs) 28 Unit Conversions 28 Powers of 10 29 Storage Units 29 Summary 30 3 What Is a Well-Tuned System? 31 Client/Server Computing 32 The Client or Front-End Machines 33 The Server 33 The Network 35 Client/Server Checklist 35 vi Oracle Performance Tuning & Optimization Host-Based Computing 36 The Front-End Application 36 The Database 36 Terminal-Based Checklist 37 Batch Computing 38 Batch-Processing Checklist 39 Exceptions 39 Multimedia Systems 39 Shipping Systems 39 Summary 40 4 Tuning Methodology 41 Goals 42 Throughput 42 Response Time 42 Connectivity 43 Fault Tolerance 43 Load Time 44 Tuning Methodology 44 Examine the Problem 45 Determine the Problem 47 Determine the Solution and Set Goals 48 Test the Solution 49 Analyze the Results 50 Summary 50 5 Benchmarking 51 Introduction to Benchmarking 52 Industry Standard Benchmarks 52 The Transaction Processing Performance Council (TPC) 53 TPC Rules and Regulations 55 Results 56 Benchmarks 57 Publication Benchmarks 69 Custom Benchmarks 70 Writing Your Own Benchmark 70 Summary 72 6 Performance Monitoring Tools 73 Oracle Tools 75 SQL*DBA Monitor 76 Server Manager 76 Oracle SNMP Agents 76 SQL Trace 76 EXPLAIN PLAN 77 vii Contents OS Tools 77 Third-Party Tools 78 Real-Time Monitors 79 Threshold Monitors 79 Summary 80 7 Performance Engineering Starts at the Design Stage 81 Design Stage 82 Database Layout 82 Indexes and Clusters 83 Application Design 83 Hardware Sizing 83 Network Considerations 84 Performance Tuning after the System Is Built 84 Tuning the Client 85 Tuning the Server 85 Tuning the Network 85 Summary 86 Part II Tuning the Server 89 8 What Affects Oracle Server Performance? 91 System Bottlenecks 92 Finding the Bottleneck 92 Removing the Bottleneck 93 System Tuning 93 Tuning RDBMS Resources 93 Tuning OS Resources 94 Tuning Hardware Resources 94 Other Tuning Factors 95 System Limitations 95 Summary 95 9 Oracle Instance Tuning 97 Tuning Memory 98 Tuning the Operating System 99 Tuning the Private SQL and PL/SQL Areas 100 Tuning the Shared Pool 100 Tuning the Buffer Cache 107 Tuning the I/O Subsystem 108 Understanding Disk Contention 109 Identifying Disk Contention Problems 110 Solving Disk Contention Problems 111 Reducing Unnecessary I/O Overhead 117 Migrated and Chained Rows 117 Dynamic Extensions 118 viii Oracle Performance Tuning & Optimization PCTFREE and PCTUSED Command Options 119 A Review of I/O Reduction Techniques 122 Tuning Rollback Segments 123 Understanding How Rollback Segments Work 123 Tuning Rollback Segments 126 Review of Rollback Segment Tuning 130 Checking for Latch Contention 130 Redo Log Buffer Contention 130 Redo Log Buffer Latch Contention 131 Tuning Checkpoints 133 Optimizing Archiving 134 Adjusting the Effect of Archiving 135 Optimizing Sorts 135 Minimizing Free List Contention 136 Summary 137 10 Performance Enhancements 139 Block Size 140 Clusters 141 Direct-Write Sorts 143 Fragmentation 144 Hash Clusters 146 When To Hash 147 Indexes 148 Index Types 149 How the Oracle Index Works 149 What To Index 150 Multiblock Reads 152 Multiblock Writes 152 Parallel Query Option 153 Parallel Query Processing 153 Direct-Write Sorts 158 Parallel Index Creation 159 Parallel Loading 159 Parallel Recovery 160 Parallel Server Option 161 Spin Counts 164 Summary 164 11 Tuning the Server Operating System 167 Goals 168 Processes 169 Memory 170 I/O 170 ix Contents Direct or Synchronous I/O 172 Asynchronous I/O 172 Miscellaneous 173 Post-Wait Semaphore 173 Scheduling and Preemption 173 Cache Affinity 174 Summary 174 12 Operating System-Specific Tuning 177 NetWare 178 Architectural Overview 178 Tuning Considerations 179 Windows NT 183 Architectural Overview 183 Tuning Considerations 185 OS/2 188 Architectural Overview 188 Tuning Considerations 188 UNIX 191 Architectural Overview 192 Tuning Considerations 192 Summary 203 13 System Processors 205 Overview of Computer Architecture 206 CPU and Cache 206 CPU Design 207 CISC Processors 207 RISC Processors 208 Multiprocessor Systems 209 SMP Systems 209 MPP Systems 209 CPU Cache 210 System Memory Architecture 210 Virtual Memory System 211 Bus Design 211 Summary 212 14 Advanced Disk I/O Concepts 213 Disk Operation 214 Seek Time 216 Rotational Latency 217 Data Transfer Rate 217 Queue Time 218 x Oracle Performance Tuning & Optimization Disk Performance 219 Random I/Os 220 Sequential I/Os 220 Summary 223 15 Disk Arrays 225 How Does a Disk Array Work? 226 Software Array 227 Hardware Array 227 RAID Technology 229 RAID-0 230 RAID-1 230 RAID-2 231 RAID-3 231 RAID-4 232 RAID-5 232 Fault-Tolerance Concerns 233 No Data Protection 233 Full Data Protection 234 Partial Data Protection 234 Configuring RAID for RDBMS Performance 235 Isolate Sequential I/Os 236 Distribute Random I/Os 237 Size the Volume Properly 238 Configure for the Disk Array 240 RAID Comparison 240 Summary 241 Part III Configuring the System 243 16 OLTP System 245 Characteristics of the OLTP System 246 Data Access Patterns 246 System Load 247 Goals 248 Design Considerations 249 Physical Data Layout 250 Hardware Considerations 253 Tuning Considerations 253 Oracle Tuning 254 Server OS Tuning 255 Enhancements 256 Oracle Parallel Server Option 257 Hardware Enhancements 257 [...]... determine where performance can be enhanced Chapter 8, “What Affects Oracle Server Performance? ” is an overview of what can effect the server performance and where bottlenecks can occur Chapter 9, Oracle Instance Tuning, reviews the bulk of instance tuning Items such as memory, I/O, and CPU usage are discussed here You also get a more in-depth look at some internal Oracle structures Chapter 10, Performance. .. associated with Oracle are the System Global Area (SGA) and the Program Global Area (PGA) 8 Chapter 1 x Introduction to Oracle Figure 1.4 The Oracle instance System Global Area (SGA) The SGA is a shared memory region Oracle uses to store data and control information for one Oracle instance The SGA is allocated when the Oracle instance starts; it is deallocated when the Oracle instance shuts down Each Oracle. .. introduced to the Transaction Processing Performance Council (TCP), their Web site, and how you can use the information available Chapter 6, Performance Monitoring Tools,” provides an overview of some of the performance monitoring tools available from Oracle and third-party vendors The chapter explains how these tools can help you investigate performance problems Chapter 7, Performance Engineering Starts at... Design Stage,” explains the holistic approach to performance engineering Performance should be engineered into every aspect of the system—from hardware selection and network configuration to database design and application development 2 Chapter 1 x Introduction to Oracle 1 Chapter Introduction to Oracle To effectively enhance the performance of your Oracle system, it is essential to understand how... are introduced to the Transaction Processing Performance Council (TCP), their Web site, and how you can use this information Chapter 6, Performance Monitoring Tools,” gives an overview of some of the performance monitoring tools available from Oracle and third-party vendors and describes how they can help you in investigating performance problems Chapter 7, Performance Engineering Starts at the Design... 291 Hardware Considerations 294 Tuning Considerations 294 Oracle Tuning 294 Server OS Tuning 295 Enhancements 296 Parallel Query Option 297 Oracle Parallel Server Option 297 Hardware Enhancements 298 Performance Verification 300 xi Oracle Performance Tuning & Optimization xii What To Test in the RDBMS 301 What... appropriate to start this book by reviewing the Oracle architecture Following the architectural overview, I give an overview of the products and services Oracle provides This introduction will leave you with an appreciation of the diversity of products Oracle offers Oracle Corporation is one of the world’s largest vendors of software for managing information Oracle has over 12,000 employees with offices... smallest pieces that make up an Oracle database; they are physically stored on disk Although the data block in most systems is 2K (2,048 bytes), you can change this size for efficiency depending on your application or operating system Sizing the data block is described in detail in Chapter 10, Performance Enhancements.” The Oracle Instance The Oracle instance consists of the Oracle processes and shared... database The instance is made up of the user processes, the Oracle background processes, and the shared memory used by these processes (see Figure 1.4) The following sections look at the various pieces that make up the Oracle instance, starting with the shared memory and continuing with the various Oracle processes The Oracle Memory Structure Oracle uses shared memory for several purposes, including... the Design Stage,” explains the holistic approach to performance engineering Performance should be engineered into every aspect of the system, from hardware selection and network configuration to database design and application development xxv Oracle Performance Tuning & Optimization Part II, “Tuning the Server,” focuses on tuning the RDBMS server The performance of the system depends on a number of factors . Products 13 Oracle RDBMS Products 13 Oracle Workgroup Server 15 Personal Oracle for Windows 16 Oracle Development Tools 16 Oracle Applications 17 Oracle Services. 81 PART II Tuning the Server 89 8 What Affects Oracle Server Performance? 91 9 Oracle Instance Tuning 97 10 Performance Enhancements 139 11 Tuning the Server