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On solving efficiently the view selection problem under bag-semantics
This item is provided by the institution :
National Technical University of Athens
Repository :
Digital Library of National Technical University of Athens | Dspace@NTUA
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ΕΚΤ item type
Conference item
(EN)
EKT year
2009
(EN)
EKT historical period
Title
On solving efficiently the view selection problem under bag-semantics (EN)
Creator
Damigos, M (EN)
Gergatsoulis, M (EN)
Afrati, F (EN)
Description
In this paper, we investigate the problem of view selection for workloads of conjunctive queries under bag semantics. In particular we aim to limit the search space of candidate viewsets. In that respect we start delineating the boundary between query workloads for which certain restricted search spaces suffice. They suffice in the sense that they do not compromise optimality in that they contain at least one of the optimal solutions. We start with the general case, where we give a tight condition that candidate views can satisfy and still the search space (thus limited) does contain at least one optimal solution. Preliminary experiments show that this reduces the size of the search space significantly. Then we study special cases. We show that for chain query workloads, taking only chain views may miss all optimum solutions, whereas, if we further limit the queries to be path queries (i.e., chain queries over a single binary relation), then path views suffice. This last result shows that in the case of path queries, taking query subexpressions suffice. © 2009 Springer Berlin Heidelberg. (EN)
Type
conferenceItem (EN)
Subject
Optimum solution (EN)
Optimal systems (EN)
Optimal solutions (EN)
Semantics (EN)
Optimality (EN)
Sub-expressions (EN)
View selection problem (EN)
Path queries (EN)
View selection (EN)
Binary relation (EN)
Search spaces (EN)
Conjunctive queries (EN)
Provider
National Technical University of Athens
Repository / collection
Digital Library of National Technical University of Athens | Dspace@NTUA
Subcollections
Κεντρική Βιβλιοθήκη Ε.Μ.Π.
Ιδρυματικό Αποθετήριο
Δημοσιεύσεις μελών Δ.Ε.Π. σε συνέδρια
Journal
Lecture Notes in Business Information Processing (EN)
Issued
2009 (EN)
Identifier
http://hdl.handle.net/123456789/35831
12 (EN)
18651348 (EN)
28 (EN)
10.1007/978-3-642-03422-0_2 (EN)
27 LNBIP (EN)
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