Reference Work Entry

Encyclopedia of Database Systems

pp 1713-1714

Memory Locality

  • Stefan Manegold


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.


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