The HiPAC project: combining active databases and timing constraints

TLDR

The HiPAC project tackles two key challenges in time‑constrained data management: managing timing constraints in databases and eliminating wasteful polling by embedding situation‑action rules monitored by the DBMS’s condition monitor. The project investigates scheduling strategies for time‑constrained tasks and transactions, designing an architecture that emphasizes the interaction between the active DBMS and the operating system. A rich knowledge model defines timing constraints, situation‑action rules, and precipitating events, while an execution model permits various coupling modes between transactions, evaluations, and actions to ensure correct concurrent execution, and performance models assess the resulting design alternatives.

Abstract

The HiPAC (High Performance ACtive database system) project addresses two critical problems in time-constrained data management: the handling of timing constraints in databases, and the avoidance of wasteful polling through the use of situation-action rules that are an integral part of the database and are monitored by DBMS's condition monitor. A rich knowledge model provides the necessary primitives for definition of timing constraints, situation-action rules, and precipitating events. The execution model allows various coupling modes between transactions, situation evaluations and actions, and provides the framework for correct concurrent execution of transactions and triggered actions. Different approaches to scheduling of time-constrained tasks and transactions are explored and an architecture is being designed with special emphasis on the interaction of the time-constrained, active DBMS and the operating system. Performance models are developed to evaluate the various design alternatives.