Agile manufacturing systems can benefit significantly from a database support. This paper describes AMDS, an agile manufacturing database system designed for capturing and manipulating the operational data of a manufacturing cell. AMDS is a continuous data-gathering real-time DBMS, and it can be logged either locally or remotely and 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 paper gives an overview of AMDS and its real-time features.

We develop and experimentally evaluate a real-time distributed relational prototype database system that permits the specification of time constraints for relational algebra queries and evaluates queries in parallel over distributed sites in a completely replicated data environment.We develop, implement and evaluate on multiple server sites iterative distributed query evaluation techniques.The risk of overspending the time constraint at each iteration is controlled using a probabilistic risk cent rol technique.The query execution plan is designed to restructure a query into an equivalent, esay-to-parallelize form, and distributed execution is achieved by multi-threaded processes and RPC calls.