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Why is n_distinct always -1 for range types? - Mailing list pgsql-performance

From Josh Berkus
Subject Why is n_distinct always -1 for range types?
Date
Msg-id 523B62CF.5080502@agliodbs.com
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Responses Re: Why is n_distinct always -1 for range types?  (Peter Geoghegan <peter.geoghegan86@gmail.com>)
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Test:

1. create a table with a range type column.
2. insert 1000 identical values into that column.
3. analyze
4. n-distinct will still be listed as -1 (unique) for the column.

Why?

--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com

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