搜索引擎中混合型分布式索引组织策略

针对搜索引擎中索引组织策略在查询性能和可扩展性等方面存在的问题，提出了一种混合型分布式索引组织策略（Loc-Glob）。该策略整合了局部和全局索引组织的基本思路，首先将搜索引擎系统的索引服务器从逻辑上分为若干个索引服务器池，索引数据先以局部（或全局）索引组织策略分配到索引服务器池上。然后，在索引服务器池的内部，索引继续以全局（或局部）索引组织的方式存储到各索引服务器上。混合型的索引组织策略较局部和全局索引组织策略具有更好的可扩展性。实验结果表明，该策略较全局索引组织策略在查询性能、负载均衡方面都有所提升，与局部索引组织策略的查询性能基本相当，并具备较高的负载均衡水平。

Hybrid strategy to distributed index organization in search engine

A hybrid index organization strategy named Loc-Glob was proposed to enhance the query performance and scalability in search engine. Loc-Glob integrates two well-studied index partitioning schemes, which are widely used in search engines. Firstly, index is partitioned according to local (or global) index organization strategy, taking cluster of some index servers as a single machine. Then, index distributed to certain cluster are further partitioned to index servers according to the global (or local) index organization strategy inside the cluster. Loc-Glob is more scalable than the traditional strategies to accommodate the explosively growing web pages. Experimental results indicate that the throughput of Loc-Glob outperforms the global index organization while it is very close to the local index organization, and Loc-Glob provides good load-balancing level.