Encyclopedia of Database Systems

2018 Edition
| Editors: Ling Liu, M. Tamer Özsu

Inter-operator Parallelism

  • Esther PacittiEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-8265-9_1085


Pipelined and independent parallelism


Inter-operator parallelism enables different operators of the query to be executed in parallel, i.e., by different nodes. Given an operator tree for a query, there are two forms of inter-query parallelism: pipelined and independent parallelism. With pipelined parallelism, an operator that consumes data produced by another operator can proceed in parallel to that operator, as soon as it receives some data. With independent parallelism, two operators with no data dependency can proceed in parallel.

Key Points

Inter-operator parallelism is very attractive when the query is complex, i.e., has many operators on different relations. Thus, the more complex the query, the more opportunities there are for inter-operator parallelism. With pipeline parallelism, operators with a producer-consumer dependency can be executed in parallel. For instance, a select operator can be executed in parallel with the subsequent join operator. The...

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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.INRIA and LINAUniversity of NantesNantesFrance

Section editors and affiliations

  • Patrick Valduriez
    • 1
  1. 1.INRIALINANantesFrance