Guide to Distributed Transactions

Version 6.1

Part No. A40826-1

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Preface

Oracle Rdb software is a general-purpose database management system based on the relational model. Oracle Rdb, using the two-phase commit protocol, coordinates the activity of transaction components across multiple databases to ensure the integrity of transactions and to maintain logical consistency among distributed transactions.

This manual describes the two-phase commit protocol, how to start and complete distributed transactions using SQL and how to recover databases from unresolved transactions using Oracle RMU commands.

Intended Audience

This manual is intended for experienced programmers who write and maintain database applications that access more than one database in a transaction or that attach to a database more than once in a transaction.

To get the most out of this manual, you should understand database concepts and terminology, particularly how to start and end transactions. In addition, you should be experienced in programming in a high-level language and be familiar with the SQL interface.

How This Manual Is Organized

This book contains the following chapters and appendixes:

Chapter 1 Introduces the two-phase commit protocol and distributed transactions, and explains when to use distributed transactions.

Chapter 2 Explains how distributed transactions work.

Chapter 3 Describes considerations in designing databases and applications for use with distributed transactions.

Chapter 4 Describes how to use distributed transactions with the SQL module language and precompiled SQL.

Chapter 5 Describes how to complete unresolved transactions using Oracle RMU commands.

Appendix A Summarizes problems that are unique to distributed transactions and suggests solutions to those problems.

Related Manuals

For more information on Oracle Rdb, see the other manuals in this documentation set, especially the following:

Oracle Rdb7 Guide to SQL Programming
Oracle Rdb7 Guide to Database Design and Definition
Oracle Rdb7 Guide to Database Maintenance
Oracle Rdb7 SQL Reference Manual
Oracle RMU Reference Manual

See the Oracle Rdb7 Release Notes for a complete list of the manuals in the Oracle Rdb documentation set.

Conventions

Oracle Rdb refers to Oracle Rdb for OpenVMS Alpha, Oracle Rdb for OpenVMS VAX, and software.

The OpenVMS Alpha operating system and the OpenVMS VAX operating system are referred to as OpenVMS.

The SQL interface to Oracle Rdb is referred to as SQL. This interface is the Oracle Rdb implementation of the SQL standard ANSI X3.135-1992, ISO 9075:1992, commonly referred to as the ANSI/ISO SQL standard or SQL92.

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Discussions in this manual that refer to VMScluster environments apply to both VAXcluster systems that include only VAX nodes and VMScluster systems that include at least one Alpha node, unless indicated otherwise.

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Chapter 1	Introduces the two-phase commit protocol and distributed transactions, and explains when to use distributed transactions.
Chapter 2	Explains how distributed transactions work.
Chapter 3	Describes considerations in designing databases and applications for use with distributed transactions.
Chapter 4	Describes how to use distributed transactions with the SQL module language and precompiled SQL.
Chapter 5	Describes how to complete unresolved transactions using Oracle RMU commands.
Appendix A	Summarizes problems that are unique to distributed transactions and suggests solutions to those problems.

. . .	Vertical ellipsis points in an example mean that information not directly related to the example has been omitted.
...	Horizontal ellipsis points in statements or commands mean that parts of the statement or command not directly related to the example have been omitted.
e, f, t	Index entries in the printed manual may have a lowercase e, f, or t following the page number; the e, f, or t is a reference to the example, figure, or table, respectively, on that page.
< >	Angle brackets enclose user-supplied information.
$	The dollar sign represents the DIGITAL Command Language prompt. This symbol indicates that the DCL interpreter is ready for input.