Oracle Database 12c DBA Handbook

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Oracle TIGHT / Oracle Database 12c DBA Handbook / Bob Bryla / 878-1/ Blind folio: i

Oracle Database 12c DBA Handbook

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Oracle TIGHT / Oracle Database 12c DBA Handbook / Bob Bryla / 878-1 / Blind folio: ii

About the AuthorBob Bryla is an Oracle 9i, 10g, 11g, and 12c Certified Professional with more than 20 years of experience in database design, database application development, training, and Oracle database administration. He is the primary Oracle DBA and database systems engineer at Epic in Verona, Wisconsin. He is a technical editor for a number of Oracle Press books, including several certification study guides for Oracle Database 10g, 11g, and 12c. He has also been known to watch science fiction movies and tinker with Android devices in his spare time.

About the Technical EditorScott Gossett is a technical director in the Oracle Advanced Technologies Solutions organization with more than 23 years of experience specializing in Oracle RAC, performance tuning, and high-availability databases. Prior to becoming a technical director, Scott was a senior principal instructor for Oracle Education for over 12 years, primarily teaching Oracle internals, performance tuning, RAC, and database administration. In addition, Scott is one of the architects and primary authors of the Oracle Certified Master exam. Scott has been a technical editor for twelve Oracle Press books.

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Oracle TIGHT / Oracle Database 12c DBA Handbook / Bob Bryla / 878-1/ Blind folio: iii

Oracle Database 12c DBA Handbook

Bob Bryla

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Copyright 2015 by McGraw-Hill Education (Publisher). All rights reserved. Except as permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written permission of the publisher, with the exception that the program listings may be entered, stored, and executed in a computer system, but they may not be reproduced for publication.

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To the gang at home: I couldnt have done it without you! And the pizzas. And the

heavy metal. And several shows on the BBC.

BB

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Oracle TIGHT / Oracle Database 12c DBA Handbook / Bob Bryla / 878-1 Oracle TIGHT / Oracle Database 12c DBA Handbook / Bob Bryla / 878-1

Contents at a Glance

PART IDatabase Architecture

1 Getting Started with the Oracle Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2 Upgrading to Oracle Database 12c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

3 Planning and Managing Tablespaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

4 Physical Database Layouts and Storage Management . . . . . . . . . . . . . . . . . . . . . . 77

PART IIDatabase Management

5 Developing and Implementing Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

6 Monitoring Space Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

7 Managing Transactions with Undo Tablespaces . . . . . . . . . . . . . . . . . . . . . . . . . . . 209

8 Database Tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245

9 In-Memory Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293

10 Database Security and Auditing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303

11 Multitenant Database Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371

PART IIIHigh Availability

12 Real Application Clusters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441

13 Backup and Recovery Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453

14 Using Recovery Manager (RMAN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481

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viii Oracle Database 12c DBA Handbook

15 Oracle Data Guard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 537

16 Miscellaneous High Availability Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 559

PART IVNetworked Oracle

17 Oracle Net . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 577

18 Managing Large Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 611

19 Managing Distributed Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 697

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Contents

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiii

PART IDatabase Architecture

1 Getting Started with the Oracle Architecture . . . . . . . . . . . . . . . . . . . . . . . . 3An Overview of Databases and Instances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Instances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Oracle Logical Storage Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Tablespaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Extents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Segments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Oracle Logical Database Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Users and Schemas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Sequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Synonyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23PL/SQL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23External File Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Database Links and Remote Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Oracle Physical Storage Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Datafiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Redo Log Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

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x Oracle Database 12c DBA Handbook

Control Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Archived Log Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Initialization Parameter Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Alert and Trace Log Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29Backup Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Oracle Managed Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Password Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Multiplexing Database Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Automatic Storage Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Manual Multiplexing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Oracle Memory Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33System Global Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Program Global Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36Software Code Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36Background Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Backup/Recovery Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39Export/Import . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39Offline Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Online Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40RMAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Security Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41Privileges and Roles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41Auditing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41Fine-Grained Auditing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42Virtual Private Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42Label Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Real Application Clusters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42Oracle Streams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Oracle Enterprise Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Oracle Initialization Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Basic Initialization Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44Advanced Initialization Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

2 Upgrading to Oracle Database 12c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51Choosing an Upgrade Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53Before Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54Using the Database Upgrade Assistant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55Performing a Manual Direct Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56Using Data Pump Export and Import . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Export and Import Versions to Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58Performing the Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Using the Data-Copying Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59After Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

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Contents xix Oracle Database 12c DBA Handbook

3 Planning and Managing Tablespaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61Tablespace Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Tablespace Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62Optimal Flexible Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Oracle Installation Tablespaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74SYSAUX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74TEMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74UNDOTBS1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74USERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75EXAMPLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Segment Segregation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

4 Physical Database Layouts and Storage Management . . . . . . . . . . . . . . . . . . 77Traditional Disk Space Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Resizing Tablespaces and Datafiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78Moving Datafiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86Moving Online Redo Log Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90Moving Control Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Automatic Storage Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93ASM Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94Creating an ASM Instance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94ASM Instance Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97ASM Dynamic Performance Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99ASM Filename Formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99ASM File Types and Templates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102Administering ASM Disk Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

PART IIDatabase Management

5 Developing and Implementing Applications . . . . . . . . . . . . . . . . . . . . . . . . . 117Tuning by Design: Best Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Do As Little As Possible . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119Do It As Simply As Possible . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121Tell the Database What It Needs to Know . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123Maximize the Throughput in the Environment . . . . . . . . . . . . . . . . . . . . . . . . . 124Divide and Conquer Your Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124Test Correctly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125Standard Deliverables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Resource Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130Implementing the Database Resource Manager . . . . . . . . . . . . . . . . . . . . . . . . 130Sizing Database Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135Using Global Temporary Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

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Supporting Tables Based on Abstract Datatypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142Using Object Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143Security for Abstract Datatypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146Indexing Abstract Datatype Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

Quiescing and Suspending the Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149Supporting Iterative Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

Iterative Column Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151Forcing Cursor Sharing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

Managing Package Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153Generating Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153Space Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153Tuning Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153Security Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153Data Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154Version Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154Execution Plans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154Acceptance Test Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154The Testing Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

6 Monitoring Space Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157Common Space Management Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

Running Out of Free Space in a Tablespace . . . . . . . . . . . . . . . . . . . . . . . . . . . 159Insufficient Space for Temporary Segments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159Too Much or Too Little Undo Space Allocated . . . . . . . . . . . . . . . . . . . . . . . . . 159Fragmented Tablespaces and Segments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

Oracle Segments, Extents, and Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161Data Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161Extents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163Segments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

Data Dictionary Views and Dynamic Performance Views . . . . . . . . . . . . . . . . . . . . . . . 165DBA_TABLESPACES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165DBA_SEGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166DBA_EXTENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166DBA_FREE_SPACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167DBA_LMT_FREE_SPACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167DBA_THRESHOLDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167DBA_OUTSTANDING_ALERTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168DBA_OBJECT_USAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168DBA_ALERT_HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168V$ALERT_TYPES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169V$UNDOSTAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169V$SORT_SEGMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169V$TEMPSEG_USAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

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Space Management Methodologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170Locally Managed Tablespaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170Using OMF to Manage Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172Bigfile Tablespaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173Automatic Storage Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174Undo Management Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

SYSAUX Monitoring and Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177Archived Redo Log File Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179Built-in Space Management Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

Segment Advisor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179Undo Advisor and the Automatic Workload Repository . . . . . . . . . . . . . . . . . . 182Index Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184Space Usage Warning Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185Resumable Space Allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187Managing Alert and Trace Files with ADR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190OS Space Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

Space Management Scripts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193Segments That Cannot Allocate Additional Extents . . . . . . . . . . . . . . . . . . . . . . 193Used and Free Space by Tablespace and Datafile . . . . . . . . . . . . . . . . . . . . . . . 194

Automating and Streamlining the Notification Process . . . . . . . . . . . . . . . . . . . . . . . . . 195Using DBMS_SCHEDULER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195Cloud Control and Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

7 Managing Transactions with Undo Tablespaces . . . . . . . . . . . . . . . . . . . . . . . 209Transaction Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210Undo Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

Rollback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211Read Consistency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211Database Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212Flashback Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

Managing Undo Tablespaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212Creating Undo Tablespaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212Undo Tablespace Dynamic Performance Views . . . . . . . . . . . . . . . . . . . . . . . . 219Undo Tablespace Initialization Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219Multiple Undo Tablespaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221Sizing and Monitoring the Undo Tablespace . . . . . . . . . . . . . . . . . . . . . . . . . . . 223Read Consistency vs. Successful DML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

Flashback Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227Flashback Query . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228DBMS_FLASHBACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230Flashback Transaction Backout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232Flashback Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232Flashback Version Query . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234Flashback Transaction Query . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

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Flashback Data Archive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238Flashback and LOBs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242

Migrating to Automatic Undo Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243

8 Database Tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245Tuning Application Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247

Effective Table Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247Distribution of CPU Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248Effective Application Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249

Tuning SQL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251Impact of Order on Load Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252Additional Indexing Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253Generating Explain Plans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254

Tuning Memory Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257Managing SGA Pools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257Specifying the Size of the SGA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260Using the Cost-Based Optimizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261

Tuning Data Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262Identifying Chained Rows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262Using Index-Organized Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263Tuning Issues for Index-Organized Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264

Tuning Data Manipulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265Bulk Inserts: Using the SQL*Loader Direct Path Option . . . . . . . . . . . . . . . . . . 265Bulk Data Moves: Using External Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267Bulk Inserts: Common Traps and Successful Tricks . . . . . . . . . . . . . . . . . . . . . . 267Bulk Deletes: The TRUNCATE Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268Using Partitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

Reducing Network Traffic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270Replication of Data Using Materialized Views . . . . . . . . . . . . . . . . . . . . . . . . . 270Using Remote Procedure Calls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272

Using the Automatic Workload Repository . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273Managing Snapshots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274Managing Baselines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274Generating AWR Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274Running the Automatic Database Diagnostic Monitor Reports . . . . . . . . . . . . . 275Using Automatic SQL Tuning Advisor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275

Performance Tuning in a Multitenant Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277Tuning Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279Sizing the CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279Using Memory Advisors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282Leveraging AWR Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283Using the SQL Tuning Advisor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283

Managing Resource Allocation Within a PDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284Using Shares to Manage Inter-PDB Resources . . . . . . . . . . . . . . . . . . . . . . . . . . 284Creating and Modifying Resource Manager Plans . . . . . . . . . . . . . . . . . . . . . . . 284

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Performing Database Replay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289Analyze the Source Database Workloads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289Capture Source Database Workloads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290Process Workloads on Target System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290Replay Workloads on Target CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290Verify Replay Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290

9 In-Memory Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293Overview of Oracle In-Memory Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294

System Requirements and Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294In-Memory Case Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295

Data Dictionary Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299V$IM_SEGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299V$INMEMORY_AREA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300V$SGA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301

10 Database Security andAuditing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303Non-database Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305Database Authentication Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305

Database Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306Database Administrator Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306Operating System Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309Network Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3103-Tier Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312Client-Side Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312User Accounts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313

Database Authorization Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318Profile Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319System Privileges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326Object Privileges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329Creating, Assigning, and Maintaining Roles . . . . . . . . . . . . . . . . . . . . . . . . . . . 333Using a VPD to Implement Application Security Policies . . . . . . . . . . . . . . . . . 340

Auditing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358Auditing Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358Statement Auditing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360Privilege Auditing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364Schema Object Auditing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365Fine-Grained Auditing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366Auditing-Related Data Dictionary Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 368Protecting the Audit Trail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 368

Data Encryption Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369DBMS_CRYPTO Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369Transparent Data Encryption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370

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11 Multitenant Database Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371Understanding the Multitenant Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373

Leveraging Multitenant Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373Understanding Multitenant Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374

Provisioning in a Multitenant Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376Understanding Pluggable Database Provisioning . . . . . . . . . . . . . . . . . . . . . . . 376Configuring and Creating a CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379Understanding New Data Dictionary Views: The Sequel . . . . . . . . . . . . . . . . . . 384Creating PDBs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387Unplugging and Dropping a PDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392

Managing CDBs and PDBs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395Understanding CDB and PDB Service Names . . . . . . . . . . . . . . . . . . . . . . . . . . 395Connecting to a CDB or PDB Using SQL Developer . . . . . . . . . . . . . . . . . . . . . 396Creating Services for CDBs or PDBs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397Switching Connections Within a CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398Starting Up and Shutting Down CDBs and PDBs . . . . . . . . . . . . . . . . . . . . . . . 399Changing Parameters in a CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 406Manage Permanent and Temporary Tablespaces in CDB and PDBs . . . . . . . . . . 407

Multitenant Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410Managing Common and Local Users . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410Managing Common and Local Privileges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412Managing Common and Local Roles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413Enabling Common Users to Access Data in Specific PDBs . . . . . . . . . . . . . . . . 414

Backup and Recovery in Multitenant Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . 416Performing Backups of a CDB and All PDBs . . . . . . . . . . . . . . . . . . . . . . . . . . . 416Backing Up CDBs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420Backing Up PDBs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422Recovering from PDB Datafile Loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424Using the Data Recovery Advisor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432Identifying Block Corruption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436Duplicating PDBs Using RMAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438

PART IIIHigh Availability

12 Real Application Clusters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441Overview of Real Application Clusters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442

Hardware Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443Software Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443Network Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443Disk Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 444

RAC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 444Server Parameter File Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445RAC-Related Initialization Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446Dynamic Performance Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446

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RAC Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 448Starting Up a RAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 448Redo Logs in a RAC Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 448Undo Tablespaces in a RAC Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449Failover Scenarios and TAF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449Tuning a RAC Node . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 451

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 451

13 Backup and Recovery Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453Backup Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 454Logical Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 454Physical Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 455

Offline Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 455Online Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 456

Using Data Pump Export and Import . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 457Creating a Directory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 457Data Pump Export Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458Starting a Data Pump Export Job . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 462Data Pump Import Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 466

Implementing Offline Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474Implementing Online Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475

Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475Performing Online Database Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477

Integration of Backup Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 478Integration of Logical and Physical Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . 478Integration of Database and Operating System Backups . . . . . . . . . . . . . . . . . . 479

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480

14 Using Recovery Manager(RMAN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481RMAN Features and Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 482

RMAN Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483RMAN vs. Traditional Backup Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 484Backup Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 486

Overview of RMAN Commands and Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 487Running SQL Commands in RMAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 487Frequently Used Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488Setting Up a Repository . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 490Registering a Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 491Persisting RMAN Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493Initialization Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 497Data Dictionary and Dynamic Performance Views . . . . . . . . . . . . . . . . . . . . . . 498

Backup Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500Full Database Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500Tablespace Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503Datafile Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506Image Copy Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506

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Control File, SPFILE Backup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507Archived Redo Log Backup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509Incremental Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509Incrementally Updated Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511Incremental Backup Block Change Tracking . . . . . . . . . . . . . . . . . . . . . . . . . . . 513Using a Fast Recovery Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 515Validating Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 516

Recovery Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 519Block Media Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 519Restoring a Control File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 520Restoring a Tablespace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 520Restoring a Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 522Restoring a Datafile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 524Restoring an Entire Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 524Validating Restore Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 525Point-in-Time Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 527Data Recovery Advisor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 527

Miscellaneous Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 531Cataloging Other Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 531Catalog Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 532REPORT and LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 533

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 534

15 Oracle Data Guard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 537Data Guard Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 538

Physical vs. Logical Standby Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 539Data Protection Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 539

LOG_ARCHIVE_DEST_n Parameter Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540Creating the Standby Database Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542

Preparing the Primary Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543Creating Logical Standby Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 547

Using Real-Time Apply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549Managing Gaps in Archive Log Sequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 550Managing Roles: Switchovers and Failovers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 550

Switchovers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 550Failovers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 554

Administering the Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 555Startup and Shutdown of Physical Standby Databases . . . . . . . . . . . . . . . . . . . . 555Opening Physical Standby Databases in Read-Only Mode . . . . . . . . . . . . . . . . 556Managing Datafiles in Data Guard Environments . . . . . . . . . . . . . . . . . . . . . . . 556Performing DDL on a Logical Standby Database . . . . . . . . . . . . . . . . . . . . . . . . 557

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 557

16 Miscellaneous High Availability Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . 559Recovering Dropped Tables Using Flashback Drop . . . . . . . . . . . . . . . . . . . . . . . . . . . . 560The Flashback Database Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 562

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Using LogMiner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 564How LogMiner Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 565Extracting the Data Dictionary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 565Analyzing One or More Redo Log Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566

Online Object Reorganization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 569Creating Indexes Online . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 570Rebuilding Indexes Online . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 570Coalescing Indexes Online . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 570Rebuilding Index-Organized Tables Online . . . . . . . . . . . . . . . . . . . . . . . . . . . 570Redefining Tables Online . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 570Moving a Datafile Online . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 572

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 573

PART IVNetworked Oracle

17 Oracle Net . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 577Overview of Oracle Net . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578

Connect Descriptors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 581Net Service Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 582Replacing tnsnames.ora with Oracle Internet Directory . . . . . . . . . . . . . . . . . . 583Listeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 583

Using the Oracle Net Configuration Assistant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 588Configuring the Listener . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 588Naming Methods Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 590Local Net Service Name Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 590Directory Usage Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 591

Using the Oracle Net Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 592Starting the Listener Server Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 594Controlling the Listener Server Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 596The Oracle Connection Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 598

Using the Oracle Connection Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 599Configuring the Oracle Connection Manager . . . . . . . . . . . . . . . . . . . . . . . . . . 600Using the Connection Manager Control Utility (CMCTL) . . . . . . . . . . . . . . . . . 601

Directory Naming with Oracle Internet Directory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603Oracle Internet Directory Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603Setting Up an Oracle Internet Directory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604

Using Easy Connect Naming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604Using Database Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 605Tuning Oracle Net . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 607

Limiting Resource Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 608Using Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 609Debugging Connection Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 609

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 610

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xx Oracle Database 12c DBA Handbook

18 Managing Large Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 611Creating Tablespaces in a VLDB Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 613

Bigfile Tablespace Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 613Creating and Modifying Bigfile Tablespaces . . . . . . . . . . . . . . . . . . . . . . . . . . . 614Bigfile Tablespace ROWID Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 615DBMS_ROWID and Bigfile Tablespaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 616Using DBVERIFY with Bigfile Tablespaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . 618Bigfile Tablespace Initialization Parameter Considerations . . . . . . . . . . . . . . . . 619Bigfile Tablespace Data Dictionary Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 620

Advanced Oracle Table Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 620Index-Organized Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 621Global Temporary Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 622External Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 624Partitioned Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625Materialized Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 652

Using Bitmap Indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653Understanding Bitmap Indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653Using Bitmap Indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 654Using Bitmap Join Indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 654

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 655

19 Managing Distributed Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657Remote Queries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 659Remote Data Manipulation: Two-Phase Commit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 660Dynamic Data Replication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 661Managing Distributed Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 662

The Infrastructure: Enforcing Location Transparency . . . . . . . . . . . . . . . . . . . . . 663Managing Database Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 667Managing Database Triggers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 669Managing Materialized Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 670Using DBMS_MVIEW and DBMS_ADVISOR . . . . . . . . . . . . . . . . . . . . . . . . . . 674What Kind of Refreshes Can Be Performed? . . . . . . . . . . . . . . . . . . . . . . . . . . . 685Using Materialized Views to Alter Query Execution Paths . . . . . . . . . . . . . . . . . 689

Managing Distributed Transactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 690Resolving In-Doubt Transactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 691Commit Point Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 691

Monitoring Distributed Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 692Tuning Distributed Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 693Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 695

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 697

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Acknowledgments

Many technical books need the expertise of more than one person, and this one is no exception. The people I collaborated with for this book at Oracle Open World, Oracle Support, and in the Oracle Partner Network are too numerous to mention but all played an important role in this book.

Thanks also go out to all the people at McGraw-Hill Education who kept this book ona reasonable schedule and learned to be even more patient with me than ever before, including Paul Carlstroem and Amanda Russell. Thanks also to Scott Gossett, who gave me good advice when the theoretical met the practical.

Many of my professional colleagues at Epic were a source of both inspiration and guidance: James Slager, Scott Hinman, Joe Obbish, and Lonny Niederstadt. In this case, thewhole is truly greater than the sum of its parts.

If you have any questions or comments about any part of this book, please do not hesitate to contact me at [email protected].

Bob Bryla

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Introduction

Whether youre an experienced DBA, a new DBA, or an application developer, you need to understand how Oracle Database 12cs features can help you best meet your customers needs. In this book, you will find coverage of the newest features (including the In-Memory option) as well as ways of merging those features into the management of an Oracle database. The emphasis throughout is on managing the databases capabilities in an effective, efficient manner to deliver a quality product. The end result will be a database that is dependable, robust, secure, and extensible.

Several components are critical to this goal, and youll see all of them covered here in depth after you are introduced to the Oracle Architecture, Oracle 12c upgrade issues, and tablespace planning in Part I; a well-designed logical and physical database architecture will improve performance and ease administration by properly distributing database objects.

Youll see appropriate monitoring, security, and tuning strategies for standalone and networked databases in Part II of this book. Backup and recovery strategies are provided to help ensure the databases recoverability. Each section focuses on both the features and the proper planning and management techniques for each area. Scalability and manageability are undeniably the biggest enhancements in Oracle Database 12c. Using pluggable databases (also known as multitenant or container databases) utilizes your server resources more effectively than single-instance pre-Oracle Database 12c databases, which means you can run many more database instances on a given server with the same performance as if you were running them on different servers. Because its easy and fast to unplug a pluggable database from a container database and plug it back into another container database, youcan migrate one or more pluggable databases to other servers when the need arises.

High availability is covered in all of its flavors in Part III: an introduction to Real Application Clusters (RAC), an extensive exposition on Recovery Manager (RMAN), and an overview ofhow to administer an Oracle Data Guard environment are a few of the topics covered in Part III.

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xxiv Oracle Database 12c DBA Handbook

Networking issues and the management of distributed and client/server databases are thoroughly covered. Oracle Net, networking configurations, materialized views, location transparency, and everything else you need to successfully implement a distributed or client/server database are described in detail in Part IV of this book. Youll also find real-world examples for every major configuration.

In addition to the commands needed to perform DBA activities, you will also see the Oracle Enterprise Manager Cloud Control 12c web pages from which you can perform similar functions. By following the techniques in this book, your systems can be designed and implemented so well that tuning efforts will be minimal. Administering the database will become easier as the users get a better product, while the database worksand works well.

Last but not least, no book with code samples would be complete without providing you the source code for the examples. Please visit www.OraclePressBooks.com to get the code sample file 12c DBA Handbook Code Listings .zip .

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http://www.OraclePressBooks.com

Oracle TIGHT / Oracle Database 12c DBA Handbook / Bob Bryla / 878-1 / Blind folio 1

PARTI

Database Architecture

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Oracle TIGHT / Oracle Database 12c DBA Handbook / Bob Bryla / 878-1 Blind folio: 3

CHAPTER1

Getting Started with the Oracle Architecture

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4 Oracle Database 12c DBA Handbook

Oracle Database 12c is an evolutionary step from the previous release, Oracle Database 11g, which, in turn, was a truly revolutionary step from Oracle Database 10g in terms of its set it and forget it features. Oracle 12c continues the tradition of feature enhancement by making execution plan management more automated, adding new virtualization features, and significantly improving availability and failover capabilities. Part I of this book covers the basics of the Oracle architecture and lays the foundation for deploying a successful Oracle infrastructure by giving practical advice for a new installation or upgrading from a previous release of Oracle. Toprovide a good foundation for the Oracle 12c software, I cover server hardware and operating system configuration issues in the relevant sections.

In Part II of this book, I will cover several areas relevant to the day-to-day maintenance and operation of an Oracle 12c database. The first chapter in Part II discusses the requirements that a DBA needs to gather long before you mount the Oracle ISO image on your server. Successive chapters deal with ways the DBA can manage disk space, CPU usage, and adjust Oracle parameters to optimize the servers resources, using a variety of tools at the DBAs disposal for monitoring database performance. Query optimization in Oracle 12c is more automated than ever with the option to change a query plan on the fly if the optimizer sees that its original estimates for cardinality were off by a significant factor.

Part III of this book focuses on the high-availability aspects of Oracle 12c. This includes using Oracles Recovery Manager (RMAN) to perform and automate database backups and recovery, along with other features, such as Oracle Data Guard, to provide a reliable and easy way to recover from a database failure. Features new to Oracle 12c such as container databases (multitenant databases) with their corresponding pluggable databases extend the concept of transportable tablespaces to the entire database in addition to more efficiently using the resources of a server hosting one or more container databases. Last, but certainly not least, we will explore how Oracle 12c Real Application Clusters (RAC) can at the same time provide extreme scalability and transparent failover capabilities to a database environment. Even if you dont use Oracle 12cs RAC features, the standby features make Oracle 12c almost as available as a clustered solution; being able to easily switch between standby and primary databases as well as query aphysical standby database provides a robust high-availability solution until you are ready to implement a RAC database.

In Part IV of this book, we will cover a variety of issues revolving around Networked Oracle. We cover not only how Oracle Net can be configured in an N-tier environment, but also howwe manage large and distributed databases that may reside in neighboring cities or around the world.

In this chapter, we cover the basics of Oracle Database 12c, highlighting many of the features we will cover in the rest of the book as well as the basics of installing Oracle 12c using Oracle Universal Installer (OUI) and the Database Configuration Assistant (DBCA). We will take a tour of the elements that compose an instance of Oracle 12c, ranging from memory structures and disk structures to initialization parameters, tables, indexes, and PL/SQL. Each of these elements plays a large role in making Oracle 12c a highly scalable, available, and secure environment.

An Overview of Databases and InstancesAlthough the terms database and instance are often used interchangeably, they are quite different. They are very distinct entities in an Oracle datacenter, as you shall see in the following sections.

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Chapter 1: Getting Started with the Oracle Architecture 5

DatabasesA database is a collection of data on disk in one or more files on a database server that collects and maintains related information. The database consists of various physical and logical structures, the table being the most important logical structure in the database. A table consists of rows and columns containing related data. At a minimum, a database must have at least tables to store useful information. Figure 1-1 shows a sample table containing four rows and three columns. The data in each row of the table is related: Each row contains information about a particular employee in the company.

In addition, a database provides a level of security to prevent unauthorized access to the data. Oracle Database 12c provides many mechanisms to facilitate the security necessary to keep confidential data confidential. Oracle Security and access control are covered in more detail in Chapter 9.

Files composing a database fall into two broad categories: database files and non-database files. The distinction lies in what kind of data is stored in each. Database files contain data and metadata; non-database files contain initialization parameters, logging information, and so forth. Database files are critical to the ongoing operation of the database on a moment-by-moment basis. Each of these physical storage structures is discussed later, in the section titled Oracle Physical Storage Structures.

InstancesThe main components of a typical enterprise server are one or more CPUs (each with multiple cores), disk space, and memory. Whereas the Oracle database is stored on a servers disk, an Oracle instance exists in the servers memory. An Oracle instance is composed of a large block of memory allocated in an area called the System Global Area (SGA), along with a number of background processes that interact between the SGA and the database files on disk.

FIGURE 1-1. Sample database table

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In an Oracle RAC, more than one instance will use the same database. Although the instances that share the database can be on the same server, most likely the instances will be on separate servers that are connected by a high-speed interconnect and access a database that resides on a specialized RAID-enabled disk subsystem. An Oracle Exadata database appliance is an example of database servers, I/O servers, and disk storage combined into one or more cabinets and is optimized for a RAC environment including dual InfiniBand interfaces to connect all of these devices at speeds up to 40 Gbps per interface. More details on how a RAC installation is configured are provided in Chapter 11.

Oracle Logical Storage StructuresThe datafiles in an Oracle database are grouped together into one or more tablespaces. Within each tablespace, the logical database structures, such as tables and indexes, are segments that are further subdivided into extents and blocks. This logical subdivision of storage allows Oracle to have more efficient control over disk space usage. Figure 1-2 shows the relationship between the logical storage structures in a database.

TablespacesAn Oracle tablespace consists of one or more datafiles; a datafile can be a part of one and only one tablespace. For an installation of Oracle 12c, a minimum of two tablespaces are created: theSYSTEM tablespace and the SYSAUX tablespace; a default installation of Oracle 12c creates six tablespaces.

FIGURE 1-2. Logical storage structures

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Chapter 1: Getting Started with the Oracle Architecture 7

Oracle Database 10g and later allow you to create a special kind of tablespace called a bigfile tablespace, which can be as large as 128TB (terabytes). Using bigfiles makes tablespace management completely transparent to the DBA; in other words, the DBA can manage the tablespace as a unit without worrying about the size and structure of the underlying datafiles.

Using Oracle Managed Files (OMF) can make tablespace datafile management even easier. With OMF, the DBA specifies one or more locations in the file system where datafiles, control files, and redo log files will reside, and Oracle automatically handles the naming and management of these files. I discuss OMF in more detail in Chapter 4.

If a tablespace is temporary, the tablespace itself is permanent; only the segments saved in the tablespace are temporary. A temporary tablespace can be used for sorting operations and for tables that exist only for the duration of the users session. Dedicating a tablespace for these kinds of operations helps to reduce the I/O contention between temporary segments and permanent segments stored in another tablespace, such as tables.

Tablespaces can be either dictionary managed or locally managed. In a dictionary-managed tablespace, extent management is recorded in data dictionary tables. Therefore, even if all application tables are in the USERS tablespace, the SYSTEM tablespace will still be accessed for managing Data Manipulation Language (DML) on application tables. Because all users and applications must use the SYSTEM tablespace for extent management, this creates a potential bottleneck for write-intensive applications. In a locally managed tablespace, Oracle maintains a bitmap in each datafile of the tablespace to track space availability. Only quotas are managed in the data dictionary, dramatically reducing the contention for data dictionary tables. There is really no good reason for creating dictionary-managed tablespaces. When you install Oracle 12c, the SYSTEM and SYSAUX tablespaces must be locally managed. For importing transportable tablespaces, a tablespace can be dictionary managed but it will be read-only.

BlocksA database block is the smallest unit of storage in the Oracle database. The size of a block is a specific number of bytes of storage within a given tablespace within the database.

A block is usually a multiple of the operating system block size to facilitate efficient disk I/O. The default block size is specified by the Oracle initialization parameter DB_BLOCK_SIZE. As many as four other block sizes may be defined for other tablespaces in the database, although the blocks in the SYSTEM, SYSAUX, and any temporary tablespaces must be of the size DB_BLOCK_SIZE.

The default block size is 8K and all Oracle testing is performed using 8K blocks. Oracle best practices suggest using an 8K block size for all tablespaces unless there is a compelling reason to use a different size. One reason could be that the average row length for a table is 20K. Therefore, you might choose to use 32K blocks, but you should fully test to see if there is a performance gain.

ExtentsThe extent is the next level of logical grouping in the database. An extent consists of one or more database blocks. When you enlarge a database object, the space added to the object is allocated as an extent.

SegmentsThe next level of logical grouping in a database is the segment. A segment is a group of extents that form a database object that Oracle treats as a unit, such as a table or index. As a result, this is typically the smallest unit of storage that an end user of the database will deal with. Four types of

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segments are found in an Oracle database: table segments (non-partitioned tables and each partition of a partitioned table), index segments, temporary segments, and rollback segments.

Data SegmentEvery table in the database resides in a single data segment, consisting of one or more extents; Oracle allocates more than one segment for a table if it is a partitioned table or a clustered table. Partitioned and clustered tables are discussed later in this chapter. Data segments include LOB (large object) segments that store LOB data referenced by a LOB locator column in a table segment (if the LOB is not stored inline in the table).

Index SegmentEach index is stored in its own index segment. As with partitioned tables, each partition of a partitioned index is stored in its own segment. Included in this category are LOB index segments; a tables non-LOB columns, a tables LOB columns, and the LOBs associated indexes can all reside in their own tablespace to improve performance.

Temporary SegmentWhen a users SQL statement needs disk space to complete an operation, such as a sorting operatio

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