Posted on 2011-05-06
Last Modified: 2012-05-11
When I use DBCC SHOW_STATISTICS there is a column named Desity.

Does 1 = High desity and 0 = Low desity?
Question by:Mr_Shaw
    LVL 16

    Expert Comment

    by:Imran Javed Zia

    Calculated as 1 / distinct values for all values in the first key column of the statistics object, excluding the histogram boundary values. This Density value is not used by the query optimizer and is displayed for backward compatibility with versions before SQL Server 2008

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    Author Comment

    Sometimes the column shows 1 or 0.

    What does 0 mean?
    LVL 16

    Expert Comment

    by:Imran Javed Zia
    The results returned indicate the selectivity of an index (the lower the density returned, the more selective the index is) and provide the basis for determining whether an index is useful to the query optimizer. The results returned are based on distribution steps of the index.
    LVL 16

    Accepted Solution

    More duplicates = high density.
    The less duplicates the lower the density

    So in a column that has ALL Duplciates you should see a density of 1
    In a col with few to no duplciates it should be a very small number (1.000E-4) or maybe 0

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