Offering a Precision-Performance Tradeoff for Aggregation Queries over Replicated Data

Strict consistency of replicated data is infeasible or not required by many distributed applications, so current systems often permit stale replication, in which cached copies of data values are allowed to become out of date. Queries over cached data return an answer quickly, but the stale answer may be unboundedly imprecise. Alternatively, queries over remote master data return a precise answer, but with potentially poor performance. To bridge the gap between these two extremes, we propose a new class of replication systems called TRAPP (Tradeoff in Replication Precision and Performance). TRAPP systems give each user fine-grained control over the tradeoff between precision and performance: Caches store ranges that are guaranteed to bound the current data values, instead of storing stale exact values. Users supply a quantitative precision constraint along with each query. To answer a query, TRAPP systems automatically select a combination of locally cached bounds and exact master data...

• Type: Conference
• Year: 2000
• Where: VLDB
• Authors: Chris Olston, Jennifer Widom
• Keywords: Database, Precise Answer, Precision Constraints, TRAPP Systems, VLDB 2000