Distributed logging for transaction processing

Abstract

Increased interest in using workstations and small processors for distributed transaction processing raises the question of how to implement the logs needed for transaction recovery. Although logs can be implemented with data written to duplexed disks on each processing node, this paper argues there are advantages if log data is written to multiple log server nodes. A simple analysis of expected logging loads leads to the conclusion that a high performance, microprocessor based processing node can support a log server if it uses efficient communication protocols and low latency, non volatile storage to buffer log data. The buffer is needed to reduce the processing time per log record and to increase throughput to the logging disk. An interface to the log servers using simple, robust, and efficient protocols is presented. Also described are the disk data structures that the log servers use. This paper concludes with a brief discussion of remaining design issues, the status of a prototype implementation, and plans for its completion.