Optimized Theta-Join Processing
Abstract
The Theta-Join is a powerful operation to connect tuples of different relational tables based on arbitrary conditions. The operation is a fundamental requirement for many data-driven use cases, such as data cleaning, consistency checking, and hypothesis testing. However, processing theta-joins without equality predicates is an expensive operation, because basically all database management systems (DBMSs) translate theta-joins into a Cartesian product with a post-filter for non-matching tuple pairs. This seems to be necessary, because most join optimization techniques, such as indexing, hashing, bloom-filters, or sorting, do not work for theta-joins with combinations of inequality predicates based on <, ?, ?, ?, >. In this paper, we therefore study and evaluate optimization approaches for the efficient execution of theta-joins. More specifically, we propose a theta-join algorithm that exploits the high selectivity of theta-joins to prune most join candidates early; the algorithm also parallelizes and distributes the processing (over CPU cores and compute nodes, respectively) for scalable query processing. The algorithm is baked into our distributed in-memory database system prototype A2DB. Our evaluation on various real-world and synthetic datasets shows that A2DB significantly outperforms existing single-machine DBMSs including PostgreSQL and distributed data processing systems, such as Apache SparkSQL, in processing highly selective theta-join queries.
- Citation
- BibTeX
Weise, J., Schmidl, S. & Papenbrock, T.,
(2021).
Optimized Theta-Join Processing.
In:
, ., , . & , .
(Hrsg.),
BTW 2021.
Gesellschaft für Informatik, Bonn.
(S. 59-78).
DOI: 10.18420/btw2021-03
@inproceedings{mci/Weise2021,
author = {Weise, Julian AND Schmidl, Sebastian AND Papenbrock, Thorsten},
title = {Optimized Theta-Join Processing},
booktitle = {BTW 2021},
year = {2021},
editor = {Kai-Uwe Sattler AND Melanie Herschel AND Wolfgang Lehner} ,
pages = { 59-78 } ,
doi = { 10.18420/btw2021-03 },
publisher = {Gesellschaft für Informatik, Bonn},
address = {}
}
author = {Weise, Julian AND Schmidl, Sebastian AND Papenbrock, Thorsten},
title = {Optimized Theta-Join Processing},
booktitle = {BTW 2021},
year = {2021},
editor = {Kai-Uwe Sattler AND Melanie Herschel AND Wolfgang Lehner} ,
pages = { 59-78 } ,
doi = { 10.18420/btw2021-03 },
publisher = {Gesellschaft für Informatik, Bonn},
address = {}
}
Sollte hier kein Volltext (PDF) verlinkt sein, dann kann es sein, dass dieser aus verschiedenen Gruenden (z.B. Lizenzen oder Copyright) nur in einer anderen Digital Library verfuegbar ist. Versuchen Sie in diesem Fall einen Zugriff ueber die verlinkte DOI: 10.18420/btw2021-03
Haben Sie fehlerhafte Angaben entdeckt? Sagen Sie uns Bescheid: Send Feedback
More Info
DOI: 10.18420/btw2021-03
ISBN: 978-3-88579-705-0
ISSN: 1617-5468
xmlui.MetaDataDisplay.field.date: 2021
Language:
(en)
