Ah adaptive concurrency control strategy for distributed database systems

Performance of a Concurrency Control Algorithm (CCA) managing a distributed database system will deteriorate considerably when the configuration of the network supporting it will change due to either communication link failures or the communication delays introduced by varying load patterns. To get a good performance in spite of the changing configurations, we propose a scheme that involves breaking down the network into ‘weakly connected’ clusters. The problem to identify the clusters of a network is NP-hard. However, we present a heuristic strategy to identify the clusters of a network that works in polynomial time. Any of the present CCAs can be modified to work on a network that is partitioned into clusters by our scheme that uses (what we term as) multiple controllers. As an example, we present a Centralized Locking Algorithm with Acknowledgment using Multiple Controllers (CLAA/MC). Performance gain achieved using multiple controllers is also discussed.