We propose a new framework for resource allocation based on concepts from microeconomics. Specifically, we address the difficult problem of managing resources in a multiple-query environment composed of queries with widely varying resource requirements. The central element of the framework is a resource broker that realizes a profit by "selling" resources to competing operators using a performance-based "currency." The guiding principle for brokering resources is profit maximization. In other words, since the currency is derived from the performance objective, the broker can achieve the best performance by making the scheduling and resource allocation decisions that maximize profit. Moreover, the broker employs dynamic techniques and adapts by changing previous allocation decisions while queries are executing. In a first validation study of the framework, we developed a prototype broker that manages memory and disk bandwidth for a multi-user query workload. The performance objective for the prototype broker is to minimize slowdown with the constraint of fairness. Slowdown measures how much higher the response time is in a multi-user environment than a single-user environment, and fairness measures how even is the degradation in response time among all queries as the system load increases, Our simulation results show the viability of the broker framework and the effectiveness of our query admission and resource allocation policies for multi-user workloads.

Emerging database application domains demand not only high functionality, but also high performance. To satisfy these two requirements, the Volcano query execution engine combines the efficient use of parallelism on a wide variety of computer architectures with an extensible set of query processing operators that can be nested into arbitrarily complex query evaluation plans. Volcano's novel exchange operator permits designing, developing, debugging, and tuning data manipulation operators in single-process environments but executing them in various forms of parallelism. The exchange operator shields the data manipulation operators from all parallelism issues. The design and implementation of the generalized exchange operator are examined. The authors justify their decision to support hierarchical architectures and argue that the exchange operator offers a significant advantage for development and maintenance of database query processing software. They discuss the integration of bit vector filtering into the exchange operator paradigm with only minor modifications.>