Full Disjunctions: Polynomial-Delay Iterators in Action

Sara Cohen, Itzhak Fadida, Yaron Kanza, Benny Kimelfeld, Yehoshua Sagiv

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

26 Scopus citations

Abstract

Full disjunctions are an associative extension of the outerjoin operator to an arbitrary number of relations. Their main advantage is the ability to maximally combine data from different relations while preserving all the original information. An algorithm for efficiently computing full disjunctions is presented. This algorithm is superior to previous ones in three ways. First, it is the first algorithm that computes a full disjunction with a polynomial delay between tuples. Hence, it can be implemented as an iterator that produces a stream of tuples, which is important in many cases (e.g., pipelined query processing and Web applications). Second, the total runtime is linear in the size of the output. Third, the algorithm employs a novel optimization that divides the relation schemes into biconnected components, uses a separate iterator for each component and applies outerjoins whenever possible. Combining efficiently full disjunctions with standard SQL operators is discussed. Experiments show the superiority of our algorithm over the state of the art.

Original languageAmerican English
Title of host publicationVLDB 2006 - Proceedings of the 32nd International Conference on Very Large Data Bases
PublisherAssociation for Computing Machinery
Pages739-750
Number of pages12
ISBN (Print)1595933859, 9781595933850
StatePublished - 2006
Externally publishedYes
Event32nd International Conference on Very Large Data Bases, VLDB 2006 - Seoul, Korea, Republic of
Duration: 12 Sep 200615 Sep 2006

Publication series

NameVLDB 2006 - Proceedings of the 32nd International Conference on Very Large Data Bases

Conference

Conference32nd International Conference on Very Large Data Bases, VLDB 2006
Country/TerritoryKorea, Republic of
CitySeoul
Period12/09/0615/09/06

Bibliographical note

Publisher Copyright:
Copyright 2006 VLDB Endowment, ACM

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