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A generalized join algorithm

dc.contributor.authorGraefe, Goetz
dc.contributor.editorHärder, Theo
dc.contributor.editorLehner, Wolfgang
dc.contributor.editorMitschang, Bernhard
dc.contributor.editorSchöning, Harald
dc.contributor.editorSchwarz, Holger
dc.date.accessioned2019-01-17T10:36:44Z
dc.date.available2019-01-17T10:36:44Z
dc.date.issued2011
dc.description.abstractDatabase query processing traditionally relies on three alternative join algorithms: index nested loops join exploits an index on its inner input, merge join exploits sorted inputs, and hash join exploits differences in the sizes of the join inputs. Cost-based query optimization chooses the most appropriate algorithm for each query and for each operation. Un- fortunately, mistaken algorithm choices during compile-time query optimization are common yet expensive to investigate and to resolve. Our goal is to end mistaken choices among join algorithms by replacing the three traditional join algorithms with a single one. Like merge join, this new join algorithm exploits sorted inputs. Like hash join, it exploits different input sizes for unsorted inputs. In fact, for unsorted inputs, the cost functions for recursive hash join and for hybrid hash join have guided our search for the new join algorithm. In consequence, the new join algorithm can replace both merge join and hash join in a database management system. The in-memory components of the new join algorithm employ indexes. If the database contains indexes for one (or both) of the inputs, the new join can exploit persistent indexes instead of temporary in-memory indexes. Using database indexes to match input records, the new join algorithm can also replace index nested loops join. Results from an implementation of the core algorithm are reported.en
dc.identifier.isbn978-3-88579-274-1
dc.identifier.pissn1617-5468
dc.identifier.urihttps://dl.gi.de/handle/20.500.12116/19583
dc.language.isoen
dc.publisherGesellschaft für Informatik e.V.
dc.relation.ispartofDatenbanksysteme für Business, Technologie und Web (BTW)
dc.relation.ispartofseriesLecture Notes in Informatics (LNI) - Proceedings, Volume P-180
dc.titleA generalized join algorithmen
dc.typeText/Conference Paper
gi.citation.endPage286
gi.citation.publisherPlaceBonn
gi.citation.startPage267
gi.conference.date02.-04.03.2011
gi.conference.locationKaiserslautern
gi.conference.sessiontitleRegular Research Papers

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