Message Ordering based Global Concurrency Control in Multidatabase Systems

A. Moon and H. Namgoong (Korea)


Multidatabase, Global Concurrency Control, MessagingOriented Middleware


A multidatabase system is designed to provide universal access to distributed data across multiple autonomous, heterogeneous local database systems (LDBSs) through worldwide network. In this paper, we propose a new approach to global concurrency control (GCC) algorithm in multidatabase system. The proposed scheme is based on a combination of ideas from messaging-oriented middlewares and GCC. A necessary condition of GCC for maintaining global serializability in a multidatabase system is that all global transactions are serialized in the same order at the all the LDBSs at which they execute. To do so, we use the rich feature of messaging-oriented middlewares, message order. If all operations of a transaction are sent in a single message and arrive at all nodes in the same order, it is possible for all receiving nodes to perform subtransactions in the same order. That is, this allows us to determine the relative serialization order of global transactions with ease; hence, it can provide a local autonomy without any information about the serialization order of transactions executing locally and give the guarantee of avoiding global deadlocks.

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