a0004 01 expert oracle database architectur morebook vn 2325

5300FM.qxd 8/22/05 4:35 PM Page i Expert Oracle Database Architecture 9i and 10g Programming Techniques and Solutions Thomas Kyte 5300FM.qxd 8/22/05 4:35 PM Page ii Expert Oracle Database Architecture: 9i and 10g Programming Techniques and Solutions Copyright © 2005 by Thomas Kyte All rights reserved No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval system, without the prior written permission of the copyright owner and the publisher ISBN (pbk): 1-59059-530-0 Printed and bound in the United States of America Trademarked names may appear in this book Rather than use a trademark symbol with every occurrence of a trademarked name, we use the names only in an editorial fashion and to the benefit of the trademark owner, with no intention of infringement of the trademark Lead Editor: Tony Davis Technical Reviewer: Jonathan Lewis, Roderick Manalac, Michael Möller, Gabe Romanescu Editorial Board: Steve Anglin, Dan Appleman, Ewan Buckingham, Gary Cornell, Tony Davis, Jason Gilmore, Jonathan Hassell, Chris Mills, Dominic Shakeshaft, Jim Sumser Associate Publisher: Grace Wong Project Manager: Sofia Marchant Copy Edit Manager: Nicole LeClerc Assistant Production Director: Kari Brooks-Copony Production Editor: Katie Stence Compositor: Dina Quan Proofreader: Linda Marousek Indexer: Broccoli Information Management Artist: Kinetic Publishing Services, LLC Interior Designer: Van Winkle Design Group Cover Designer: Kurt Krames Manufacturing Director: Tom Debolski Distributed to the book trade worldwide by Springer-Verlag New York, Inc., 233 Spring Street, 6th Floor, New York, NY 10013 Phone 1-800-SPRINGER, fax 201-348-4505, e-mail orders-ny@springer-sbm.com, or visit http://www.springeronline.com For information on translations, please contact Apress directly at 2560 Ninth Street, Suite 219, Berkeley, CA 94710 Phone 510-549-5930, fax 510-549-5939, e-mail info@apress.com, or visit http://www.apress.com The information in this book is distributed on an “as is” basis, without warranty Although every precaution has been taken in the preparation of this work, neither the author(s) nor Apress shall have any liability to any person or entity with respect to any loss or damage caused or alleged to be caused directly or indirectly by the information contained in this work The source code for this book is available to readers at http://www.apress.com in the Source Code section 5300FM.qxd 8/22/05 4:35 PM Page iii Contents Foreword xi About the Author xiv About the Technical Reviewers xv Acknowledgments xvi Introduction xvii Setting Up Your Environment xxv ■CHAPTER Developing Successful Oracle Applications My Approach The Black Box Approach How (and How Not) to Develop Database Applications Understanding Oracle Architecture Understanding Concurrency Control 15 Multi-Versioning 20 Database Independence? 26 “How Do I Make It Run Faster?” 42 The DBA–Developer Relationship 46 Summary 47 ■CHAPTER Architecture Overview 49 Defining Database and Instance 50 The SGA and Background Processes 55 Connecting to Oracle 57 Dedicated Server 57 Shared Server 59 Mechanics of Connecting over TCP/IP 60 Summary 62 iii 5300FM.qxd iv 8/22/05 4:35 PM Page iv ■CONTENTS ■CHAPTER Files 65 Parameter Files 66 What Are Parameters? 67 Legacy init.ora Parameter Files 69 Server Parameter Files (SPFILEs) 71 Parameter File Wrap-Up 78 Trace Files 78 Requested Trace Files 79 Trace Files Generated in Response to Internal Errors 83 Trace File Wrap-Up 85 Alert File 85 Data Files 88 A Brief Review of File System Mechanisms 89 The Storage Hierarchy in an Oracle Database 90 Dictionary-Managed and Locally-Managed Tablespaces 94 Temp Files 96 Control Files 98 Redo Log Files 98 Online Redo Log 99 Archived Redo Log 101 Password Files 103 Change Tracking File 106 Flashback Log Files 107 Flashback Database 107 Flash Recovery Area 108 DMP Files (EXP/IMP Files) 108 Data Pump Files 110 Flat Files 113 Summary 114 ■CHAPTER Memory Structures 115 The Process Global Area and User Global Area 115 Manual PGA Memory Management 116 Automatic PGA Memory Management 123 Choosing Between Manual and Auto Memory Management 133 PGA and UGA Wrap-Up 135 The System Global Area 135 Fixed SGA 139 Redo Buffer 140 5300INDEX.qxd 8/22/05 4:33 PM Page 723 ■INDEX transaction address (TADDR), 324 transaction API, 18 transaction ID, 210 transaction isolation levels concurrency control, 232 dirty read, 232 non-repeatable read, 232 overview, 232–34 phantom read, 233 READ COMMITTED, 235–37 READ ONLY, 233, 241–42 READ UNCOMMITTED, 233–35 REPEATABLE READ, 233, 237–39 SERIALIZABLE, 233, 239–41 SQL/92 standard, 232 transaction locks See TX (transaction) locks transaction-level atomicity, 262 transactions atomicity overview, 257 procedure-level atomicity, 259–62 statement-level atomicity, 257–59 transaction-level atomicity, 262 autonomous transactions how they work, 275–77 overview, 275 when to use, 277–81 bad transaction habits committing in a loop, 266, 268–72 overview, 265–66 using autocommit, 272 distributed transactions, 273–74 integrity constraints and transactions DEFERRABLE constraints and cascading updates, 263–65 IMMEDIATE constraints, 262–63 overview, 262 overview, 255 transaction control statements, 256–57 Transparent Network Substrate (TNS), 60 triggers, 307, 626 TRIM function, 498, 666 true temporary tablespace, 94–95 TRUNC function, 525 TRUNCATE function, 342, 679 TRUNCATE option, 652, 679 tuning database, 42 two-phase commit (2PC), 174 TX (transaction) locks, 209–15, 229, 231 DML locks, 209 INITRANS parameter, 214 MAXTRANS parameter, 214 transactional mechanisms, 209 using, 210 Type2 undo segment type, 340 U Undo, 21, 25, 248 See also redo; rollback generating, 323 how works with redo, 287–91 introduction, 323 issues with undo segments, 323 ORA-01555: snapshot too old error, 325 delayed block cleanout, 332–36 overview, 325–26 undo segments are too small, 326–32 overview, 283, 323 redo log buffer, 287 and temporary tables, 319–22 what generates most and least undo, 323–25 UNDO_RETENTION clause, 326, 551 UNIFORM locally-managed tablespaces, 634–37, 639 UNIFORM SIZE tablespace, 631 UNIFORM tablespace, 636 UNIFORM_TEST, 636 unique index, 424 unloader PL/SQL utility control file, 693 RUN function, 696 unloading data in SQLLDR friendly format, 692 unloading data, 692, 701–3 UNRECOVERABLE clause, 310 unused indexes, reasons for, 475 functions used implicitly on columns, 477 functions used on columns, 477 index on nullable columns, 477 index used to be slower, 481 index would be slower, 480 leading edge of index not used in query, 475 UPDATE GLOBAL INDEXES clause, 597 UPDATE statement, 203, 234, 246, 248, 268, 307, 323, 394, 474 UPDATE trigger, 581 UPDATE/INSERT, 639 updates blocked, 203 cascading, 263–65 lost, preventing, 17–20 UPPER function, 660 UROWID data type, 491 US7ASCII character set, 492 USER, 88 User Global Area (UGA), 115–17, 119–20, 126, 130–31 USER_DUMP_DEST parameter, 80 USER_IND_EXPRESSIONS view, 467 USER_INDEXES view, 444 user-defined locks, 229 723 5300INDEX.qxd 724 8/22/05 4:33 PM Page 724 ■INDEX utility background processes CJQ0 and Jnnn processes (job queues), 179–80 CTWR (change tracking processes), 181 database architecture, 178 EMNn (event monitor processes), 180 MMAN (memory manager), 180 MMON, MMNL, and Mnnn (manageability monitors), 180 overview, 179 QMNC and Qnnn (advanced queues), 180 QMNn, 180 RVWR (recovery writer), 181 SNPn, 179 UTL_FILE function, 693 UTL_FILE function, Windows, 694 UTL_FILE tool, 113 UTL_MAIL, 252 UTL_RAW variable, 668 UTL_RAW.CAST_TO_VARCHAR2 package, 673 UTL_SMTP, 252 V V$ view, 78, 170 V$CONTROLFILE, 54 V$DATAFILE, 54 V$INSTANCE view, 81 V$LOCK table, 211–17 V$LOCK view, V$LOGFILE, 54 V$MYSTAT view, 300, 302 V$PARAMETER view, 67, 81 V$PROCESS view, 81 V$SESSION table, 39, 211, 622, 625 V$SESSION view, 81 V$SGA_DYNAMIC_COMPONENTS view, 138 V$SGASTAT view, 135 V$SQL, V$STATNAME view, 300 V$TRANSACTION table, 211, 625 V$UNDOSTAT command, 270 VALUES ( DEFAULT ) clause, 576 VAR attribute, 663, 667 VARCHAR2 data type, 490, 499 VARCHAR2 object, 417 VARCHAR2 type, 496, 502, 541 vendor extensions, 35 vendor-specific database features, 31 version column, optimistic locking using, 190–93 vertical scaling, 177 VIEW_TEXT column, 516 views, 471 Visual Basic code, 41 VSIZE function, 509 W WAIT method, 216 watch_stat.sql script, 118, 125, 127 WE8ISO8859P1 character set, 492, 669 willing to wait mode, 221 WORKAREA_SIZE_POLICY parameter, 124 write consistency consistent reads and current reads, 247–49 importance of restart, 252–53 overview, 246–47 seeing a restart, 249–52 WRITEAPPEND package, 673 X X$ tables, 142 X$BH table, 142 Y YEAR TO MONTH type, 537 ... 8/22/05 4:35 PM Page i Expert Oracle Database Architecture 9i and 10g Programming Techniques and Solutions Thomas Kyte 5300FM.qxd 8/22/05 4:35 PM Page ii Expert Oracle Database Architecture: 9i and... Understanding Oracle Architecture Understanding Concurrency Control 15 Multi-Versioning 20 Database. .. Successful Oracle Applications My Approach The Black Box Approach How (and How Not) to Develop Database