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Statistics, Data Distribution, and Cardinality

  • Grant Fritchey
Chapter

Abstract

By now, you should have a good understanding of the importance of indexes. But, the index alone is not what the optimizer uses to determine how it’s going to access data. The optimizer must have information about the data that defines an index or a column. That information is referred to as a statistic. Statistics define both the distribution of data and the uniqueness or selectivity of the data. Statistics are maintained both on indexes and on columns within the system. You can even define statistics manually yourself.

Keywords

Execution Plan Query Optimizer Select Statement Automatic Statistic Base Table 
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.

Copyright information

© Grant Fritchey 2014

Authors and Affiliations

  • Grant Fritchey
    • 1
  1. 1.MAUS

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