Block access estimation for clustered data

A method is proposed for dealing with nonuniform data distributions in database organizations in order to estimate the expected number of blocks containing the tuples requested by a query. When tuples with equal attribute value are not uniformly distributed over the blocks of secondary memory that s...

Full description

Saved in:
Bibliographic Details
Published in:IEEE transactions on knowledge and data engineering 1993-08, Vol.5 (4), p.712-718
Main Author: Ciaccia, P.
Format: Article
Language:English
Subjects:
Applied sciences
Artificial intelligence
Computer science
control theory
systems
Econometrics
Economic forecasting
Exact sciences and technology
Expert systems
Information systems. Data bases
Knowledge acquisition
Knowledge engineering
Machine intelligence
Medical expert systems
Memory organisation. Data processing
Psychology
Software
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:A method is proposed for dealing with nonuniform data distributions in database organizations in order to estimate the expected number of blocks containing the tuples requested by a query. When tuples with equal attribute value are not uniformly distributed over the blocks of secondary memory that store the relation, a clustering effect is observed. This can be detected by means of a single parameter, the clustering factor, which can be stored in the system catalog. The method can be applied to uniform data distributions as well, since it is shown that a uniform distribution can be viewed as a particular instance of a class of clustered distributions. In this case the proposed method allows considerable reduction of the number of computational steps needed to compute the estimated result.< >
ISSN:1041-4347
1558-2191
DOI:10.1109/69.234782