Fine-grained Non-blocking Join Algorithm Based on XJoin
Xianghong Tang · 2009
Wide-area distribution raises significant performance problems for traditional query processing techniques as data access becomes less predictable due to link congestion,load imbalances,and temporary outages.Non-blocking joi-ning query execution is a promising approach to coping with unpredictability in unreliable network and hiding intermi-ttent delays in data arrival by reactively scheduling background processing.Classical non-blocking two-way joining technique such as XJoin fail to deliver acceptable performance in such a scenario where gradually augmenting partition could not be dealt with during one relatively short intermittent delay.We developed a novel reactively-scheduled non-blocking join,called XJoin-FG,disparting one coarse-grained transaction into several parts according to the size of interval time.XJoin-FG employed fine-grained timestamp mechanism to avoid duplicate results.Using the optimization implementation along with emulational data obtained by monitoring Internet data delivery,we show that XJoin-FG is an effective solution for providing fast query responses to users even in the presence of the longer-term of data sources appeared as una-vailability.