Consistency-Aware Evaluation of OLAP Queries in Replicated Data Warehouses
OLAP tools for distributed data warehouses generally assume underlying replicated tables are up to date. Unfortunately, maintaining updated replicas is difficult due to the inherent tradeoff between consistency and availability. In this paper, the authors propose techniques to evaluate OLAP queries in distributed data warehouses assuming a lazy replication model. Considering that it may be admissible to evaluate OLAP queries with slightly outdated replicated tables, their technique first efficiently computes the degree of obsolescence of replicated local tables and when such result is acceptable, given an error threshold, then the query is evaluated locally, avoiding the transmission of large tables over the network.