Window Function Expression: Let the Self-join Enter

Kód výsledku v 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>

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

Window Function Expression: Let the Self-join Enter

Popis výsledku v původním jazyce

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&apos; ability to select an appropriate strategy. The article&apos;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.

Název v anglickém jazyce

Window Function Expression: Let the Self-join Enter

Popis výsledku anglicky

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&apos; ability to select an appropriate strategy. The article&apos;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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10201 - Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8)

Projekt

—

Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Proceedings of the VLDB Endowment. Volume 14

ISSN

2150-8097

e-ISSN

—

Svazek periodika

17

Číslo periodika v rámci svazku

9

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

13

Strana od-do

2162-2174

Kód UT WoS článku

001308222700004

EID výsledku v databázi Scopus

—