Memory Aware Query Routing in Interactive Web-Based Information Systems

Abstract

Query throughput is one of the primary optimization goals in interactive web-based information systems in order to achieve the performance necessary to serve large user communities. Queries in this application domain differ significantly from those in traditional database applications: they are of lower complexity and almost exclusively read-only. The architecture we propose here is specifically tailored to take advantage of the query characteristics. It is based on a large parallel shared-nothing database cluster where each node runs a separate server with a fully replicated copy of the database. A query is assigned and entirely executed on one single node avoiding network contention or synchronization effects. However, the actual key to enhanced throughput is a resource efficient scheduling of the arriving queries. We develop a simple and robust scheduling scheme that takes the currently memory resident data at each server into account and trades off memory re-use and execution time, reordering queries as necessary. Our experimental evaluation demonstrates the effectiveness when scaling the system beyond hundreds of nodes showing super-linear speedup.

The leganet system: Freshness-aware transaction routing in a database cluster

“…Its solution fits well for some applications, such as XML document management [15] or read-intensive OLAP queries [39]. For interactive Web-based information systems, the scheduling algorithm of [51] is tailored for low-complexity read only queries, and requires detailed information about every query operator. However, none of these solutions addresses the problem of seamless integration of legacy applications.…”