On optimal processor allocation to support pipelined hash joins

Abstract

In this paper, we develop algorithms to achieve optimal processor allocation for pipelined hash joins in a multiprocessor-based database system. A pipeline of hash joins is composed of several stages, each of which is associated with one join operation. The whole pipeline is executed in two phases: 1993 the table-building phase, and (2) the tuple-probing phase. We focus on the problem of allocating processors to the stages of a pipeline to minimize the query execution time. We formulate the processor allocation problem as a two-phase mini-max optimization problem, and develop three optimal allocation schemes under three different constraints. The effectiveness of our problem formulation and solution is verified through a detailed tuple-by-tuple simulation of pipelined hash joins. Our solution scheme is general and applicable to any optimal resource allocation problem formulated as a two-phase mini-max problem. © 1993, ACM. All rights reserved.