Dwarfs in the rearview mirror: how big are they really?

Online-Analytical Processing (OLAP) has been a field of competing technologies for the past ten years. One of the still unsolved challenges of OLAP is how to provide quick response times on any Terabyte-sized business data problem. Recently, a very clever multi-dimensional index structure termed Dwarf [26] has been proposed offering excellent query response times as well as unmatched index compression rates. The proposed index seems to scale well for both large data sets as well as high dimensions. Motivated by these surprisingly excellent results, we take a look into the rearview mirror. We have re-implemented the Dwarf index from scratch and make three contributions. First, we successfully repeat several of the experiments of the original paper. Second, we substantially correct some of the experimental results reported by the inventors. Some of our results differ by orders of magnitude. To better understand these differences, we provide additional experiments that better explain the...

• Type: Journal
• Year: 2008
• Where: PVLDB
• Authors: Jens Dittrich, Lukas Blunschi, Marcos Antonio Vaz Salles
• Keywords: Clever Multi-dimensional Index, Dwarf, Dwarf Index, PVLDB 2008