Showing papers on "Two-phase commit protocol published in 1981"

The Recovery Manager of the System R Database Manager

Abstract: The recovery subsystem of an experimental data management system is described and evaluated. The transactmn concept allows application programs to commit, abort, or partially undo their effects. The DO-UNDO-REDO protocol allows new recoverable types and operations to be added to the recovery system Apphcation programs can record data m the transaction log to facilitate application-specific recovery. Transaction undo and redo are based on records kept in a transaction log. The checkpoint mechanism is based on differential fries (shadows). The recovery log is recorded on disk rather than tape.

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 consistent state. The Transaction Monitoring Facility (TMF), is a component of the ENCOMPASS distributed data management system, which runs on the Tandem [TM] computer system. TMF provides continuous, fault-tolerant transaction processing in a decentralized, distributed environment. Recovery from failures is transparent to user programs and does not require system halt or restart. Recovery from a failure which directly affects active transactions, such as the failure of a participating processor or the loss of communications between participating network nodes, is accomplished by means of the backout and restart of affected transactions. The implementation utilizes distributed audit trails of data base activity and a decentralized transaction concurrency control mechanism.

Database concurrency control and recovery in local broadcast networks

Abstract: Some large business database systems are characterized by a high volume of short transactions (e.g. credit/debit account). In such systems, data retrieval costs are fixed and unavoidable. However, overhead due to concurrency control and recovery protocols may be reduced resulting in higher throughput and shorter response times. This research addresses the problems of concurrency control and recovery (collectively referred to as transaction management) in very large business applications. It is felt that traditional solutions to the problem (i.e. ever-larger centralized machines) will be inadequate as applications grow. An architecture for a database management system distributed over a local broadcast network is proposed. A "passive" concurrency control technique is presented which makes use of the broadcast nature of the communications bus. By eavesdropping for request messages on the broadcast bus, a single concurrency control node can perform conflict analysis for the entire system without explicit lock messages. Two algorithms are presented and shown robust with respect to communication and processor failures: a passive locking algorithm and a passive non-locking algorithm. Simulation results indicate that the passive schemes have very low overhead and perform better than corresponding distributed algorithms. Also, the cost of the recovery protocol necessary to ensure atomic commit at all sites (i.e. the distributed two-phase commit protocol) is shown to be quite high and, in many cases, overshadows the cost of concurrency control.