移动环境下缓存弱一致性的研究

Weak Cache Coherency in Mobile Environments

在移动环境下,客户缓存为提高客户-服务器数据库系统的整体性能提供了有效途径。缓存与服务方数据的同步策略是缓存研究的重要内容。移动环境下,考虑到网络的带宽、开销和可靠性等因素,客户有可能允许缓存维护弱一致性,即允许缓存与服务方数据存在偏差。本文针对基于语义的缓存,给出客户限定偏差范围的方法,并且提出基于有效期的缓存同步算法。

Under mobile environments, client caching provides an effective way to improve client-server database system performance. How to maintain cache coherency is an important issue in caching research. Because of the low bandwidth and high expense of wireless network, it will cost a lot to maintain strong cache coherency. Furthermore, considering the factors of bandwith, overhead and reliability, the client may allow the cache to maintain weak coherency. That is to say, the client allows a divergence between the cache and the data of the server. Based on semantic cache, this paper presents a way to define the allowed divergence, and proposes a cache coherence algorithm based on the period of validity.