Theoretical Evidence for the Superiority of LRU-2 over LRU for the Paging Problem

  • Joan Boyar
  • Martin R. Ehmsen
  • Kim S. Larsen
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4368)


The paging algorithm LRU-2 was proposed for use in data-base disk buffering and shown experimentally to perform better than LRU [O’Neil, O’Neil, and Weikum, 1993]. We compare LRU-2 and LRU theoretically, using both the standard competitive analysis and the newer relative worst order analysis. The competitive ratio for LRU-2 is shown to be 2k for cache size k, which is worse than LRU’s competitive ratio of k. However, using relative worst order analysis, we show that LRU-2 and LRU are asymptotically comparable in LRU-2’s favor, giving a theoretical justification for the experimental results.


Competitive Ratio Online Algorithm Theoretical Evidence Subsidiary Policy Page Fault 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2007

Authors and Affiliations

  • Joan Boyar
    • 1
  • Martin R. Ehmsen
    • 1
  • Kim S. Larsen
    • 1
  1. 1.Department of Mathematics and Computer ScienceUniversity of Southern DenmarkOdenseDenmark

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