A BI is defined
for a single attribute and the encodings are based solely on data values; the property
map (PMap) is a multidimensional indexing technique that precomputes attribute
expressions for each tuple and stores the results as bit strings. In order to determine
whether the PMap is competitive with BIs, we conduct a performance study
of the PMap with the range encoded bit sliced index (REBSI) using cost models to
simulate storage and query processing costs for different kinds of query types. We
identify parameters that have significant effect on index performance and determine
situations in which either index is more suitable. These results could be useful for
improving the performance of an analytical decision making system.
80 Davis & Gupta
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Introduction
A data warehouse is a repository of information collected from different sources.
Querying of data warehouses for decision-making in areas such as sales and marketing
planning is referred to as online analytical processing (OLAP). In the writeonce-
read-many environment of OLAP applications, multidimensional data analysis
is now increasingly used for decision support systems (DSS). Complex DSS queries
are often submitted interactively and reducing their response time is a critical issue
in the data warehousing environment (Vanichayobon & Gruenwald, 1999; Jurgens
& Lenz, 2001).
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