Performance evaluation of a distributed architecture for information retrieval

Information explosion across the Internet and elsewhere offersaccess toanincreasing number of document collections. In order for users to effectively access these collections, information retrieval (IR) systems must provide coordinated, concurrent, and distributed access. In this paper, we describe a fully functional distributed IR system based on the Inquery unified IR system. To refine this prototype, we implement a flexible simulation model that analyzes performance issues given a wide variety of system parameters and configurations. We present aseries ofexperiments that measure response time, system utilization, and identify bottlenecks. We vary numerous system parameters, such as the number of users, text collections, terms per query, and workload to ireneralize our results for other distributed IR systems. Based on our initial results, we recommend simple changes to the prototype and evaluate the changes using the simulator. Because of the significant resource demands of information retrieval, it is not difficult to generate workloads that overwhelm system resources regardless of the architecture. However under some realistic workloads. we demonstrate system organizations for which response’ time gracefully degrades as the workload increases and performance scales with the number of processors. This scalable architecture includes a surprisingly small number of brokers through which a large number of clients and servers communicate.