基于模式和数据并发更新的视图维护机制

Mechanism for View Maintenance Under Schema and Data Concurrent Updates

在数据仓库的实化视图维护处理中,如何有效地处理并发更新是一个重要而又棘手的问题.文中阐述了P2P环境下模式与数据全面并发的典型情形,分析了因并发更新而导致视图维护异常的原因,针对这些不同的方面提出相应的纠正策略.给出了一种基于时态演算的并发更新侦测方法,以及混合更新下对关联更新进行检测的有效算法,最后提出了解决乱序提交问题的增强代理机制,确保了数据仓库与数据源的一致性.

During maintaining the materialized view in the data warehouse, how to efficiently handle the concurrent updates is an important and intractable problem. The paper discusses typical situations that scheme change mixes with data updates concurrently. And the reasons why concurrent updates result in view maintenance anomy are analyzed. Based on the different situations, the corresponding correct strategy is presented. Furthermore, the paper proposes the temporal methods for detecting concurrent updates and related updates under mixing scheme change and data updates. Lastly, an enhanced commit agent is designed for deal with non-orderly commit problem. Thus, the consistency between data warehouse and data source is guaranteed.