The dangers of replication and a solution
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
Update propagation protocols for replicated databates
SIGMOD '99 Proceedings of the 1999 ACM SIGMOD international conference on Management of data
Replica Consistency in Lazy Master Replicated Databases
Distributed and Parallel Databases
Offering a Precision-Performance Tradeoff for Aggregation Queries over Replicated Data
VLDB '00 Proceedings of the 26th International Conference on Very Large Data Bases
Improving Performance in Replicated Databases through Relaxed Coherency
VLDB '95 Proceedings of the 21th International Conference on Very Large Data Bases
Efficient Snapshot Differential Algorithms for Data Warehousing
VLDB '96 Proceedings of the 22th International Conference on Very Large Data Bases
Update propagation strategies to improve freshness in lazy master replicated databases
The VLDB Journal — The International Journal on Very Large Data Bases
On-Line Analytical Processing in Distributed Data Warehouses
IDEAS '98 Proceedings of the 1998 International Symposium on Database Engineering & Applications
Set Reconciliation with Nearly Optimal Communication Complexity
Set Reconciliation with Nearly Optimal Communication Complexity
Handling big dimensions in distributed data warehouses using the DWS technique
Proceedings of the 7th ACM international workshop on Data warehousing and OLAP
The costs and limits of availability for replicated services
ACM Transactions on Computer Systems (TOCS)
An integrated approach to recovery and high availability in an updatable, distributed data warehouse
VLDB '06 Proceedings of the 32nd international conference on Very large data bases
Design and evaluation of a continuous consistency model for replicated services
OSDI'00 Proceedings of the 4th conference on Symposium on Operating System Design & Implementation - Volume 4
Measuring referential integrity in distributed databases
Proceedings of the ACM first workshop on CyberInfrastructure: information management in eScience
Set reconciliation with nearly optimal communication complexity
IEEE Transactions on Information Theory
Repairing OLAP queries in databases with referential integrity errors
DOLAP '10 Proceedings of the ACM 13th international workshop on Data warehousing and OLAP
Distributed protocols for multi-agent coalition formation: a negotiation perspective
AMT'12 Proceedings of the 8th international conference on Active Media Technology
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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, we 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, our 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. Otherwise, the query can be remotely evaluated less efficiently with the master copy of tables, provided they are stored at a single site. Inconsistency measurement is computed by adapting distributed set reconciliation algorithms to efficiently compute the symmetric difference between the master and replicated tables. Our improved distributed database algorithm has linear communication complexity and cubic time complexity in the size of the symmetric difference, which is expected to be small in a replicated data warehouse. Our technique is independent of the method employed to propagate data warehouse insertions, deletions and updates. We present experiments simulating distributed databases, with different CPU and transmission speeds, showing our method is effective to decide if the query should be evaluated either locally or remotely.