Encyclopedia of Database Systems

2009 Edition

Memory Locality

  • Stefan Manegold
Reference work entry
DOI: https://doi.org/10.1007/978-0-387-39940-9_686


Principle of locality; Locality principle; Locality of reference


Locality refers to the phenomenon that computer programs — or computational processes in general — do not access all of their data items uniformly and independently, but rather in a clustered and/or dependent/correlated manner. Some data items are accessed more often than others, repeated accesses to the same data item occur in bursts, and related items are usually accessed together, concurrently or within a short time interval.

There are two types of locality:
  1. 1.

    Temporal locality means that accesses to the same data item are grouped in time, i.e., multiple accesses to the same data item occur in rather short time intervals compared to rather long time periods where the same data item is not accessed. Hence, temporal locality is the concept that a data item that is referenced by a program at one point in time will be referenced again sometime in the near future.

  2. 2.

    Spatial localitymeans that data...

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Recommended Reading

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    Ailamaki A.G., DeWitt D.J., Hill M.D., and Skounakis M. Weaving relations for cache performance. In Proc. 27th Int. Conf. on Very Large Data Bases, 2001, pp. 169–180.Google Scholar
  2. 2.
    Denning P.J. The working set model for program behaviour. Commun. ACM, 11(5):323–333, 1968.MathSciNetCrossRefGoogle Scholar
  3. 3.
    Denning P.J. The locality principle. Commun. ACM, 48(7):19–24, 2005.CrossRefGoogle Scholar
  4. 4.
    Manegold S., Boncz P.A., and Kersten M.L. Optimizing main-memory join on modern hardware. IEEE Trans. Knowl. Data Eng., 14(4):709–730, July 2002.CrossRefGoogle Scholar
  5. 5.
    Shatdal A., Kant C., and Naughton J. Cache conscious algorithms for relational query processing. In Proc. 20th Int. Conf. on Very Large Data Bases, 1994, pp. 510–512.Google Scholar

Copyright information

© Springer Science+Business Media, LLC 2009

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  • Stefan Manegold

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