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.