Media failures usually leave database systems unavailable for several hours until recovery is complete, especially in applications with large devices and high transaction volume. Previous work introduced a technique called single-pass restore, which increases restore bandwidth and thus substantially decreases time to repair. Instant restore goes further as it permits read write access to any data on a device undergoing restore--even data not yet restored--by restoring individual data segments on demand. Thus, the restore process is guided primarily by the needs of applications, and the observed mean time to repair is effectively reduced from several hours to a few seconds. This paper presents an implementation and evaluation of instant restore. The technique is incrementally implemented on a system starting with the traditional ARIES design for logging and recovery. Experiments show that the transaction latency perceived after a media failure can be cut down to less than a second and that the overhead imposed by the technique on normal processing is minimal. The net effect is that a few "nines" of availability are added to the system using simple and low-overhead software techniques.
Transactional Information Systems is the long-awaited, comprehensive work from leading scientists in the transaction processing field. Weikum and Vossen begin with a broad look at the role of transactional technology in today's economic and scientific endeavors, then delve into critical issues faced by all practitioners, presenting today's most effective techniques for controlling concurrent access by multiple clients, recovering from system failures, and coordinating distributed transactions. The authors emphasize formal models that are easily applied across fields, that promise to remain valid as current technologies evolve, and that lend themselves to generalization and extension in the development of new classes of network-centric, functionally rich applications. This book's purpose and achievement is the presentation of the foundations of transactional systems as well as the practical aspects of the field what will help you meet today's challenges. * Provides the most advanced coverage of the topic available anywhere--along with the database background required for you to make full use of this material. * Explores transaction processing both generically as a broadly applicable set of information technology practices and specifically as a group of techniques for meeting the goals of your enterprise. * Contains information essential to developers of Web-based e-Commerce functionality--and a wide range of more "traditional" applications. * Details the algorithms underlying core transaction processing functionality. Table of Contents PART ONE - BACKGROUND AND MOTIVATION Chapter 1 What Is It All About? Chapter 2 Computational Models PART TWO - CONCURRENCY CONTROL Chapter 3 Concurrency Control: Notions of Correctness for the Page Model Chapter 4 Concurrency Control Algorithms Chapter 5 Multiversion Concurrency Control Chapter 6 Concurrency Control on Objects: Notions of Correctness Chapter 7 Concurrency Control Algorithms on Objects Chapter 8 Concurrency Control on Relational Databases Chapter 9 Concurrency Control on Search Structures Chapter 10 Implementation and Pragmatic Issues PART THREE - RECOVERY Chapter 11 Transaction Recovery Chapter 12 Crash Recovery: Notion of Correctness Chapter 13 Page Model Crash Recovery Algorithms Chapter 14 Object Model Crash Recovery Chapter 15 Special Issues of Recovery Chapter 16 Media Recovery Chapter 17 Application Recovery PART FOUR - COORDINATION OF DISTRIBUTED TRANSACTIONS Chapter 18 Distributed Concurrency Control Chapter 19 Distributed Transaction Recovery PART FIVE - APPLICATIONS AND FUTURE PERSPECTIVES Chapter 20 What Is Next?