子句间优化技术在语义缓存查询求值中的应用

缓存技术用来弥补网络通信能力的不足。语义缓存既缓存查询结果，也缓存查询语义，可更好节省网络开销。实用性是语义缓存技术产生和发展的基础，根据实用性要求，语义缓存查询求值所消耗的时空代价要远小于网络通信能力不足带来的时空代价，所以必须对求值算法进行优化。文章从语法一级分析求值算法存在的问题并给出了两级优化方法和实现技术，降低了算法复杂度，减少了对数据库的无效访问，使语义缓存技术向实用化迈进了一大步。

The Application of Optimization Technique between Clauses in Semantic Caching Query Evaluation

The caching technology is used for making up insufficient network communication capacity. Semantic caching can save network overhead by caching query result as well as query semantics. Practicality is the foundation of producing and developing semantic caching technology. According to the request of practicality, semantic caching query evaluation should cost much less space and time overhead than insufficient network traffic capacity caused. Therefore, optimizing the evaluation algorithm becomes a necessary. This article analyzed the problems of eaisting e- valuation algorithm in a grammar level, and then proposed a two-level optimized method and its realization technique, which made the semantic caching technique a big progress in practicality by reducing algorithm complexity and invalid accessing to database.