Join processing in relational databases

Mishra, Priti; Eich, Margaret H.

doi:10.1145/128762.128764

Cited by 326 publications

(149 citation statements)

References 67 publications

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“…A good example, which applies in this case, is the so-called hash-join (see e.g. [26]). The idea is to avoid enumerating all of allFaculty × allStudents when there are few matches.…”

Section: This Paper Makes the Following Contributionsmentioning

confidence: 99%

“…Even if he/she had appreciated the value of using a hash join, the optimal ordering (i.e. whether to map from names to Faculty or from names to Students) depends upon the relative number of students and faculty (mapping to the smaller is generally the best choice [26]). Of course, a clever programmer could still obtain optimal performance by manually enumerating all possible orderings and including a runtime check to select the best one.…”

Section: This Paper Makes the Following Contributionsmentioning

confidence: 99%

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Efficient Object Querying for Java

Willis

Pearce

Noble

2006

ECOOP 2006 – Object-Oriented Programming

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Abstract. Modern programming languages have little or no support for querying objects and collections. Programmers are forced to hand code such queries using nested loops, which is both cumbersome and inefficient. We demonstrate that first-class queries over objects and collections improve program readability, provide good performance and are applicable to a large number of common programming problems. We have developed a prototype extension to Java which tracks all objects in a program using AspectJ and allows first-class queries over them in the program. Our experimental findings indicate that such queries can be significantly faster than common programming idioms and within reach of hand optimised queries.

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“…A good example, which applies in this case, is the so-called hash-join (see e.g. [26]). The idea is to avoid enumerating all of allFaculty × allStudents when there are few matches.…”

Section: This Paper Makes the Following Contributionsmentioning

confidence: 99%

Section: This Paper Makes the Following Contributionsmentioning

confidence: 99%

Efficient Object Querying for Java

Willis

Pearce

Noble

2006

ECOOP 2006 – Object-Oriented Programming

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“…Zawiera on formuły umożliwiające oszacowanie liczebności zbioru wynikowego operacji złączenia i rozmiaru rekordu w zbiorze wynikowym oraz kosztu operacji złączenia przy zastosowaniu algorytmu pętli zagnieżdżonych (ang. nested loops join) [11] i kosztu operacji przesyłu danych (w przypadku danych rozproszonych).…”

Section: Analiza Problemu Optymalizacyjnegounclassified

Verification of the Search Space Exploration Strategy Based on the Solutions of the Join Ordering Problem

Kostrzewa

Josiński

2011

Advances in Intelligent and Soft Computing

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Streszczenie. Artykuł stanowi próbę oceny jakości autorskiej strategii eksploracji przestrzeni poszukiwań dla problemu określenia kolejności realizacji złączeń w zapytaniu adresowanym do bazy danych. Jakość strategii zostanie oceniona przez porównanie czasów wykonania zapytania, uzyskanych w systemie SQL Server 2008: z jednej strony przez realizację planu wygenerowanego za pomocą algorytmu IWO, z drugiej zaś -przez realizację planu wyznaczonego przez moduł optymalizacyjny systemu zarządza-nia bazą danych.Słowa kluczowe: eksploracja przestrzeni poszukiwań, określenie kolejności realizacji złączeń, algorytm IWO VERIFICATION OF THE SEARCH SPACE EXPLORATION STRATEGY BASED ON THE SOLUTIONS OF THE JOIN ORDERING PROBLEMSummary. The paper addresses the problem of quality estimation of the search space exploration strategy. The strategy is used to find a satisfying solution to the join ordering problem, which constitutes a crucial part of the database query optimization task. The method of strategy verification is based on the comparison of the execution time for the solution produced by the IWO algorithm with the execution time for the solution determined by the SQL Server 2008 optimizer.

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“…-Nested-Loop Join [11]: Given inputs sorted on the join attribute(s), the tuples are read from either R or S in turn and to find which ones is S or R (respectively) match. -Merge Join [11]: Given inputs sorted on the join attribute(s), the tuples are read from either R or S in turn and to find which ones is S or R (respectively) match. -Index Nested-Loop Join [4]: Each R-tuple is read in turn and its joint attribute(s) are then used to search an index on S and retrieve the tuples that match.…”

Section: Technical Contextmentioning

confidence: 99%

A Foundation for the Replacement of Pipelined Physical Join Operators in Adaptive Query Processing

Eurviriyanukul

Fernandes

Paton

2006

Current Trends in Database Technology – EDBT 2006

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Abstract. Adaptive query processors make decisions as to the most effective evaluation strategy for a query based on feedback received while the query is being evaluated. In essence, any of the decisions made by the optimizer (e.g., on operator order or on which operators to use) may be revisited in an adaptive query processor. This paper focuses on changes to physical operators (e.g., the specific join operators used, such as hash-join or merge-join) in pipelined query evaluators. In so doing, the paper characterizes the runtime properties of pipelined operators in a way that makes explicit when specific operators may be replaced, and that allows the validity of operator replacements to be proved. This is illustrated with reference to the substitution of join operators during their evaluation.

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Join processing in relational databases

Abstract: BIBLIOGRAPHY to combine tu~les when thev have the same course number and offering number values. The resulting tuples would contain all the offering data, as well as all the student data.

Cited by 326 publications

References 67 publications

Efficient Object Querying for Java

Efficient Object Querying for Java

Verification of the Search Space Exploration Strategy Based on the Solutions of the Join Ordering Problem

A Foundation for the Replacement of Pipelined Physical Join Operators in Adaptive Query Processing

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