Abstract

This paper presents "Positionally Encoded Record Filters " (PERFs) and describes their use in a distributed query processing technique called PERF join. A PERF is a novel two-way join reduction implementation primitive. While having the same storage and transmission efficiency as a hash filter (e.g., Bloom Filter), a PERF is based on the relation tuple scan order instead of hashing. Hence it doesn't suffer any loss of join information incurred by hash collisions. Using the query response time measured in terms of network cost as a comparison criterion, we demonstrate through analytical studies that PERF join performs significantly better than two-way Bloomjoin and two-way semijoin variants under a wide range of relevant cost parameter values. For the large number of distributed query processing algorithms relying on Bloomjoin or semijoin variants to reduce their network cost, we can sometimes gain an instant improvement in their response time by switching to PERF join instead. Other sa...

Citations