Transaction monitoring in ENCOMPASS: reliable distributed transaction processing

ABSTRACT: A transaction is- an atomic update which takes a data base from a consistent state to another c:onsistent state. The Transaction Monitoring Facility (TMF),. is a component of the ENCOMPASS distributed data management system. which runs on the Tandem computer system. TMF provides c:ontinuous. fault-tolerant transaction processing in a decentralized. distributed enviromnent. Recovery from failures is transparent to user programs and does not require system balt or restart. Recovery from a failure which directly affeets active transactions. such as the failure of a participating proc:essor or the loss of communications between participating network nodes, is accomplished by means of the baekout and restart of affected transactions. The implementation utilizes distributed audit trails of data base activity and a decentralized transaction concurrency c:ontrol meehanism.