Analysis of Transaction Management Performance

There is currently much interest in incorporating transactions into both operating systems and general purpose programming languages. This paper provides a detailed examination of the design and performance of the“¢ transaction manager of the Camelot system. Camelot is a transaction facility that provides a rich model of transactions intended to support a wide variety of general-purpose applications. The transaction manager's principal function is to execute the protocols that ensure atomicity. The conclusions of this study are: a simple optimization to two-phase commit reduces logging activity of distributed transactions; non-blocking commit is practical for some applications; multithreaded design improves throughput provided that log batching is used; multi-casting reduces the variance of distributed commit protocols in a LAN environment; and the performance of transaction mechanisms such as Camelot depend heavily upon kernel performance

Routing and Admission Control of Virtual Circuits in General Topology Networks

Emerging high speed Broadband Integrated Services Digital Networks (B-ISDN) are expected to carry traffic for services like video-on-demand and video teleconferencing which will require resource reservation along the path on which the traffic is sent. As a result, such networks will need efficient routing and admission control algorithms. The simplest approach is to use fixed paths and no admission control. More sophisticated approaches which use state dependent routing and a form of admission control called trunk reservation can be found in the circuit switching literature. However, the circuit switching literature has generally focused on fully connected (complete) networks. This paper suggests a new routing and admission control algorithm for general topology networks. Our algorithm is an adaptation of a recently discovered theoretical algorithm that is asymptotically best possible with respect to the worst case performance. The main idea behind our algorithm was to improve the per..