Enabling On-demand Query Result Caching in DotSlash for Handling Web Hotspots Effectively

DotSlash is an automated Web hotspot rescue system, which allows different Web sites to form a mutual-aid community, and use spare capacity in the community to relieve Web hotspots experienced by any individual site. DotSlash rescue services enable a Web site to build an adaptive distributed Web server system on the fly and replicate application programs dynamically, which relieve a spectrum of bottlenecks ranging from access network bandwidth to Web servers and application servers. This paper presents DotSlash Qcache services that allow a Web site to use on-demand distributed query result caching to greatly reduce the workload at read-mostly databases. The novelty of this work is that our query result caching is on demand and operated based on load conditions, which offers good data consistency for normal load and good scalability with relaxed data consistency under heavy load. DotSlash Qcache services complement DotSlash rescue services; together they provide a comprehensive solution to address different bottlenecks at multi-tier Web sites. Experiments show that using DotSlash a Web site can increase its maximum request rate supported by a factor of 10 for the RUBBoS read-only mix