Re: count * performance issue

On Tue, 11 Mar 2008 08:27:05 +0530
"Robins Tharakan" <tharakan@gmail.com> wrote:

> SELECT COUNT(*) from table WHERE indexed_field IS NULL
> +
> SELECT COUNT(*) from table WHERE indexed_field IS NOT NULL

If the selectivity is appropriate yes. However if you have 1 million
rows, and 200k of those rows are null (or not null), it is still going
to seqscan.

joshua d. drake

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