Tom Lane wrote:
> Hannu Krosing <[EMAIL PROTECTED]> writes:
> > How hard would it be to _not_ include nulls in indexes
> > as they are not used anyway.
>
> Seems to me that would be a step backwards.

    It  would cause multi-key indexes beeing unusable for partial
    key lookup. Imagine you have a key over (a, b, c)  and  query
    with  WHERE  a = 1 AND b = 2. This query cannot use the index
    if a NULL value in c  would  cause  the  index  entry  to  be
    suppressed.


Jan

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