Two-Phase Deadlock Detection Algorithm In Distributed Databases

There are two deadlock detection methods in a distributed database. One is centralized, and the other is distributed. In this paper a distributed method is discussed. Sub-Wait-Graphs, which express the state of execution of transactions in individual sites, are introduced, and a sufficient condition for a global deadlock not to occur is given, based on the Sub-Wait-Graph. This sufficient condition makes it possible for a deadlock detection to be separated into two phases, local deadlock detection and global dead-lock detection. Also, an efficient deadlock detection algorithm, which requires to be built and maintain only Sub-Wait-Graphs, is proposed, by making use of this property. The characteristics and effects of this algorithm are discussed.