Encyclopedia of Database Systems

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

Schema Tuning

  • Philippe BonnetEmail author
  • Dennis Shasha
Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-8265-9_322


Schema tuning is the activity of organizing a set of table designs in order to improve overall query and update performance.

Historical Background

Table design entails deciding which tables to implement and which attributes to put in those tables. Other sections of this encyclopedia (design theory, normalization theory) discuss a mathematical model of table design to eliminate redundancy. Sometimes however redundancy can be good for performance, so database tuners must consider the possibility of a principled incorporation of redundancy.


Normalization tends to break up the attributes of an application into separate tables. Consider the normalized schema consisting of two tables:
  • Blog(blog_id, author_id, title, numreaders) and

  • Author(author_id, author_city).

If one frequently wants to associate blogs with the city of their authors, then this table design requires a join on author_id for each of these queries. A denormalized alternative is to add author_location to

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Recommended Reading

  1. 1.
    Celko J. Joe Celko’s SQL for smarties: advanced SQL programming. 3rd ed. San Fransisco: Morgan Kaufmann; 2005.zbMATHGoogle Scholar
  2. 2.
    Kimball R, Ross M. The data warehouse toolkit: the complete guide to dimensional modeling. 2nd ed. New York: Wiley; 2002.Google Scholar
  3. 3.
    Shasha D, Bonnet P. Database tuning: principles, experiments and troubleshooting techniques. San Fransisco: Morgan Kaufmann; 2002.Google Scholar
  4. 4.
    Tow D. SQL tuning. North Sebastopol: OReilly; 2003.Google Scholar

Copyright information

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

Authors and Affiliations

  1. 1.Department of Computer ScienceIT University of CopenhagenCopenhagenDenmark
  2. 2.Department of Computer ScienceNew York UniversityNew YorkUSA

Section editors and affiliations

  • Dennis Shasha
    • 1
  1. 1.Dep. of Computer ScienceNew York Univ.New YorkUSA