Encyclopedia of Database Systems

Living Edition
| Editors: Ling Liu, M. Tamer Özsu

Inter-query Parallelism

  • Nikos HardavellasEmail author
  • Ippokratis Pandis
Living reference work entry
DOI: https://doi.org/10.1007/978-1-4899-7993-3_1556-2



Inter-query parallelism is a form of parallelism in the evaluation of database queries, in which several different queries execute concurrently on multiple processors to improve the overall throughput of the system.

Key Points

When multiple non-conflicting requests are submitted to a database management system, then the system can execute them in parallel to improve the overall throughput [1]. This form of parallelism is called inter-query parallelism. Inter-query parallelism is a consequence of the concurrency of user requests. It is orthogonal to intra-query parallelism, in which several processors cooperate for the faster execution of a single query [2]. Both forms of parallelism can co-exist in a database management system. Inter-query parallelism is common in on-line transaction processing (OLTP), where multiple concurrent users submit requests to the system. It is a challenge for the database management system to achieve high performance and maintain the ACID properties in the presence of multiple concurrently executing requests or transactions.


Recommended Reading

  1. 1.
    DeWitt DJ, Gray J. Parallel database systems: the future of high-performance database computing. Commun ACM. 1992;35(6):85–98.CrossRefGoogle Scholar
  2. 2.
    Graefe G. Encapsulation of parallelism in the volcano query processing system. In: Proceedings of the ACM SIGMOD international conference on management of data; 1990, p. 102–11.Google Scholar

Copyright information

© Springer Science+Business Media LLC 2016

Authors and Affiliations

  1. 1.Carnegie Mellon UniversityPittsburghUSA

Section editors and affiliations

  • Anastasia Ailamaki
    • 1
  1. 1.Informatique et CommunicationsEcole Polytechnique Fédérale de LausanneLausanneSwitzerland