DMVR:一种基于Cache的动态物化视图置换算法

采用硬盘cache机制实现的物化视图选择算法具有良好的动态适应能力,能够根据用户查询的变化即时地进行物化视图集的调整,但这类算法都是基于内存机制的简单移植,未考虑物化视图从硬盘回读的代价,在代价模型构建方面存在不足,为此提出一种基于cache的动态物化视图置换算法DMVR,其具有严格的数学模型,可以很好地适用于物化视图的动态选择与调整.同时为了适应系统负荷率较高的情况,又提出了DMVR的改进算法DMVR-IDLE,以保证高频度查询条件下数据仓库对用户查询仍具有较好的响应速度.实验表明DMVR算法与DMVR-IDLE算法是有效可行的.

DMVR: A Dynamic Materialized View Replacement Algorithm Based on Disk Cache Mechanism

The current dynamic materialized view selection algorithms based on disk cache can tune with the altering query requirements and possess better dynamic adaptability.However these algorithms simply refer to the memory mechanism,whithout an accurate model to take into account the cost of retrieving materialized views from disk.A dynamic materialized view replacement (DMVR) algorithm is presented, which is based on a better cost model and therefore suitable for dynamically adjusting the materialized view set.For systems with a heavy workload,that DMVR algorithm is modified to become DMVR-IDLE,which possesses and maintains a better response performance to high frequency query. Experiments have shown effectiveness of both algorithms.