Quantization in Append-Only Collections

Quantization, the pre-calculation and conversion to integers of term/document weights in an inverted index, is a well studied aspect of search engines that substantially improves retrieval efficiency. Previous work has considered the impact of quantization on effectiveness-efficiency tradeoffs in retrieval, for example, exploring the relationship between collection size and quantization range in static web collections. We extend previous work to append-only collections and examine whether quantization settings derived from prior time periods can be applied to future time periods. Experiments confirm that previous results generalize to a collection with different characteristics and with a different ranking function, and that in an append-only collection, we can use previous quantization settings in future time periods without substantial losses in either effectiveness or efficiency.