Preface

Clustering technology has been around for a long time. It was in the early 1980s that Digital Equipment Corporation (DEC) first introduced the clustered configuration called the VAXCluster. Around the same period, I started my computer career working on the PDP-11 systems, also from DEC. PDP-11s were the first platforms that were used by Oracle Corporation to develop the first relational database in 1978, when Oracle released Version 1 of the Relational Database Management System (RDBMS) product. This commercial relational database entered the market nearly 8 years after Dr. E.F. Codd first introduced the relational database model in June 1970 through his white paper entitled, “A Relational Model of Data for Large Shared Data Banks” (published at IBM, San Jose, USA).

After the initial set of VAXClusters entered the market in the early 1980s, DEC introduced a relational database called Rdb.1 This database used the VAXClusters as their primary platform, thus becoming the first commercial clustered relational database. It was during the late 1980s that I started my career in the relational database world with Rdb on VAXClusters as my first venture into the clustered arena. In 1986, Oracle also introduced the first clustered database solution called Oracle Parallel Server (OPS) with Version 5. In spite of OPS supporting a clustered environment, it did not take advantage of the clustering technology that was available, for example in VAXClusters, namely communicating via the cluster interconnect. This caused a serious performance issue, until Version 9.0 when Oracle, after inheriting some of the clustered database knowledge from Rdb and the technology from Compaq (HP recently acquired Compaq, who had previously acquired DEC), introduced Real Application Clusters (RAC).

All of this experience from VAXClusters to Rdb to OPS to RAC created this motivation to share the knowledge in the form of this book.

About this book

Compared to its predecessor (OPS), the architecture behind the RAC implementation has changed significantly. The book will discuss in detail subjects that I have never seen discussed elsewhere, for example the internals of RAC operations, cache fusion, fusion recovery, fast reconfiguration of RAC, etc.

Areas such as partitioning, types of indexes, tablespace management, transaction management, backup and recovery principles, and internals of the recovery operation have been covered extensively in this book. What good is a book on RAC that does not provide discussions on tuning? In my view, the coverage of extensive tuning, in over three chapters, starting with tools and utilities such as SQL Trace, STATSPACK, and Oracle Event and Wait interfaces, covering single instance tuning followed by cluster tuning, including tuning the cluster interconnect and cache transfer, makes this book unique.

Throughout the book, examples are provided with file dumps, followed by discussions and analysis of problem solving. The book also provides discussions on migrating to a RAC environment.

Oracle Real Application Clusters provides comprehensive coverage of the features, technology, and principles of Oracle’s RAC product, which is part of the Oracle 9i release of their RDBMS product. This book is divided into four main parts (Concepts, Architecture, Operations, and Appendices) covering various areas of the application/database design, development, and maintenance life cycles. Starting with the fundamentals, an introduction to the concepts of the various hardware architectures and the clustering technology available, the book discusses the pros and cons, leading into discussion of the RAC technology. After the formal introduction of the concepts of clustering and configurations, the book discusses the various theories of asynchronous (parallel) and synchronous processing and how they could be applied to the database tier of the enterprise architecture.

How to use this book

The chapters are written to follow one another in a logical fashion by introducing topics in the earlier chapters and building on the technology. Thus it is advised that you read the chapters in order. Even if you have worked with clustered databases, you will certainly find a nugget or two that may be new to you. For the experienced reader, the book also highlights wherever applicable the new features introduced in Oracle 9i, Oracle 9i Release 2, and Oracle 10g. The book’s four parts are outlined below.

Part I: Concepts

Information in this part is to get the reader’s feet wet. This part contains three chapters.

■ Chapter 1: Provides an overview of the modern business requirements and the criticality of these requirements in today’s Internet-based business.

■ Chapter 2: Focuses on the hardware concepts, the various types of hardware technologies such as SMP, MPP, NUMA, and the clustered SMP. The chapter also discusses the various components, such as the cluster interconnect technology and the storage systems, including various types of RAID technology.

■ Chapter 3: Discusses the basic Oracle concepts, starting with what an instance is, then covering the various background and foreground processes, including the various types of files and tablespaces that Oracle supports and uses. Data block dump analysis and data block structure, including transaction layers, are discussed.

Part II: Architecture

Once the reader’s feet are wet with regard to the concepts, the second part steps into the clustered database technology starting with the RAC architecture in Chapter 4. This part contains six chapters.

■ Chapter 4: Takes an in-depth look into the RAC architecture, the various additional background and foreground processes required by RAC, their functions, and how they work together in clustered database architecture. The role of the GCS, GES, and GRD is covered a great detail.

■ Chapter 5: Discusses the transaction management principles in general, the transaction management in a single instance configuration, and the transaction management in a RAC environment. This chapter discusses, using scenarios, the architecture behind this configuration, how the sharing of data occurs between nodes, and the sharing of data when the cluster has more than two nodes. Through examples, this chapter will explain how cache fusion helps the lock activity between the shared rows, the various lock levels, and how locks are handled, based on requests received from processes on various nodes participating in the cluster. It details the discussions concerning the cache fusion behavior in a transaction; various scenarios of clustered transaction management include the various states of GCS operation such as the PI and XI states of a block.

■ Chapter 6: Discusses the concepts of parallel processing. The advantages of using parallel processing and the appropriate usage of this feature in today’s business computing. Concepts such as working of parallel processing, parallel processing configuration scenarios, problems encountered in using parallel processing, tuning statements for parallel processing, and advantages of using parallel processing are also addressed.

■ Chapter 7: Discusses the various features of the Oracle product and the technology to be considered in designing databases for the RAC environment. The chapter discusses various types of indexes, data partitioning and materialized views, and the advantages and positive effect of the technology for a RAC environment.

■ Chapter 8: Covers the various installation and configuration steps required for RAC implementation. The chapter covers both the DBCA utility for database creation and the manual method, including configuration of the GSD, SRVCONFIG, and SRVCTL utilities, and listener configuration.

■ Chapter 9: Illustrates, lists, and describes the various RAC-related data dictionary views and parameters.

Part III: Operations

After a complete understanding of the architecture, the next step is to understand its operations, taking a step deeper and getting to the bottom of things. This part contains eight chapters.

■ Chapter 10: Describes the availability and scalability features of RAC, including transparent application failover, Oracle Real Application Cluster Guard, fast reconfiguration, and inclusion and exclusion of instances. It also discusses how to configure TAF using the tnsnames file and by making OCI-based calls directly from a Java application.

■ Chapter 11: Describes the steps involved during a migration process. Both migrating from a single instance to a clustered database environment and migrating from OPS to RAC are covered.

■ Chapter 12: Covers the backup features available, including implementation and configuration of...