Distributed processing of time-constrained queries in CASE-DB

Abstract

We design, develop and experimentally evaluate a prototype real-time distributed relational database system. This database management system (DBMS) permits the specification of time constraints for relational algebra queries and evaluates queries in parallel over distributed sites in a completely replicated data environment. Iterative distributed query evaluation techniques are developed, implemented and evaluated on multiple server sites. The risk of overspending the time constraint at each iteration is controlled using a probabilistic risk control technique. The query execution plan is designed to restructure a query into an equivalent, easy-to-parallelize form, and distributed execution is achieved through multi-threaded processes and RPC calls. Agile manufacturing systems can benefit significantly from a database support and more specifically from real-time database systems. This thesis describes AMDB, an agile manufacturing database system designed for capturing and manipulating the operational data of a manufacturing cell. AMDB is a continuous data gathering, real-time DBMS, and it can be logged either locally or remotely and can be used for off-line analysis as well. The temporal operational data obtained is used for performance and reliability analysis, high-level summary report generation, real-time monitoring and active interaction. This thesis describes the overview of AMDB, its real-time features.