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arXiv 1305.0699cs.IRcs.DB
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用于Web规模集合的主内存中的快速增量反向索引

Fast, Incremental Inverted Indexing in Main Memory for Web-Scale Collections

Nima Asadi, Jimmy Lin

摘要:

对于文本检索系统,所有数据结构驻留在主存中的假设越来越普遍。在这种情况下,我们提出了一种新的增量倒排索引算法的网络规模的集合,直接构造压缩的帖子列表在内存中。设计高效的内存算法需要理解现代处理器体系结构和存储层次结构:在本文中,我们探讨了发布列表连续性的问题。自然,占据连续内存区域的发布列表对于检索是优选的,但是保持连续性增加了复杂性并且减慢了索引。另一方面,允许不连续的索引段简化了索引构造,但降低了检索性能。理解这种权衡是我们的主要贡献:我们发现,共同定位的倒排列表段的小组产生查询评估性能,是统计上无法区分的完全连续的帖子列表。换句话说,没有必要在内存中布置数据结构,使得一个术语的所有发布都是连续的;我们可以用相对少量的工作来实现理想的性能。

英文摘要:

For text retrieval systems, the assumption that all data structures reside in main memory is increasingly common. In this context, we present a novel incremental inverted indexing algorithm for web-scale collections that directly constructs compressed postings lists in memory. Designing efficient in-memory algorithms requires understanding modern processor architectures and memory hierarchies: in this paper, we explore the issue of postings lists contiguity. Naturally, postings lists that occupy contiguous memory regions are preferred for retrieval, but maintaining contiguity increases complexity and slows indexing. On the other hand, allowing discontiguous index segments simplifies index construction but decreases retrieval performance. Understanding this tradeoff is our main contribution: We find that co-locating small groups of inverted list segments yields query evaluation performance that is statistically indistinguishable from fully-contiguous postings lists. In other words, it is not necessary to lay out in-memory data structures such that all postings for a term are contiguous; we can achieve ideal performance with a relatively small amount of effort.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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