Window Function Expression: Let the Self-join Enter
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61989100%3A27240%2F24%3A10256194" target="_blank" >RIV/61989100:27240/24:10256194 - isvavai.cz</a>
Result on the web
<a href="https://www.vldb.org/pvldb/vol17/p2162-baca.pdf" target="_blank" >https://www.vldb.org/pvldb/vol17/p2162-baca.pdf</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.14778/3665844.3665848" target="_blank" >10.14778/3665844.3665848</a>
Alternative languages
Result language
angličtina
Original language name
Window Function Expression: Let the Self-join Enter
Original language description
Window function expressions (WFEs) became part of the SQL:2003 standard, and since then, they have often been implemented in database systems (DBS). They are especially essential to OLAP DBSs, and people use them daily. Even though WFEs are a heavily used part of the SQL language, the amount of research done on their optimization in the last two decades is not significant. WFE does not extend the expressive power of the SQL language, but it makes writing SQL queries easier and more transparent. DBSs always compile SQL queries with WFE using a sequence of partition-sort-compute operators, which we call a linear strategy. Plans resulting from the linear strategy are robust and, in many cases, efficient. This article introduces an alternative strategy using a self-join, which is not considered in the current DBSs. We call it the self-join strategy, and it is based on an SQL query transformation where the result query uses a self-join query plan to compute WFE. One output of this work is a tool that can automatically perform such SQL query transformations. We created a microbenchmark showing that the self-join strategy is more effective than the linear strategy in many cases. We also performed a cost-based experiment to evaluate the query optimizers' ability to select an appropriate strategy. The article's main aim is to show that usage of the self-join strategy for queries with WFE is beneficial if selected in a cost-based manner.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10201 - Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8)
Result continuities
Project
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Continuities
S - Specificky vyzkum na vysokych skolach
Others
Publication year
2024
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Proceedings of the VLDB Endowment. Volume 14
ISSN
2150-8097
e-ISSN
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Volume of the periodical
17
Issue of the periodical within the volume
9
Country of publishing house
US - UNITED STATES
Number of pages
13
Pages from-to
2162-2174
UT code for WoS article
001308222700004
EID of the result in the Scopus database
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