Abstract Due to limited buffers and highly unpredictable traffic loads, the design of effective buffer management policies that minimize cell loss is critical to ATM networks. We outline the important characteristics of optimal buffer control policies for a single node, and using a dynamic programming formulation for a simple two-node network, gain insights into the much harder general multi-node problem. The key result we present is that simple non-work-conserving policies which use limited feedback from adjacent nodes can reduce cell loss significantly. We construct a feedback-based control that uses simple “stop-and-go” rules. This control is then enhanced to react to rapidly changing network conditions. This new control is called the Adaptive HILO policy. Simulation studies of complex networks with large delay-bandwidth product show that the Adaptive HILO policy performs impressively under diverse conditions. Using intuitive arguments, we demonstrate that this policy effectively utilizes unused buffer capacity in upstream buffers during periods of heavy load in downstream buffers.

It is well known that using conventional concurrency control techniques for obtaining serializable answers to long-running queries leads to an unacceptable drop in system performance. As a result, most current DBMSs execute such queries under a reduced degree of consistency, thus providing non-serializable answers. In this paper, we present a new and highly concurrent approach for processing large decision support queries in relational databases. In this new approach, called compensation-based query processing, concurrent updates to any data participating in a query are communicated to the query's on-line query processor, which then compensates for these updates so that the final answer reflects changes caused by the updates. Very high concurrency is achieved by locking data only briefly, while still delivering transaction-consistent answers to queries.

article Free Access Share on Performance of B-tree concurrency control algorithms Authors: V. Srinivasan Department of Computer Sciences, University of Wisconsin, Madison, WI Department of Computer Sciences, University of Wisconsin, Madison, WIView Profile , Michael J. Carey Department of Computer Sciences, University of Wisconsin, Madison, WI Department of Computer Sciences, University of Wisconsin, Madison, WIView Profile Authors Info & Claims ACM SIGMOD RecordVolume 20Issue 2June 1991 pp 416–425https://doi.org/10.1145/119995.115860Online:01 April 1991Publication History 67citation1,031DownloadsMetricsTotal Citations67Total Downloads1,031Last 12 Months52Last 6 weeks20 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF