Re: pg_stats explained ... ? - Mailing list pgsql-hackers

From Tom Lane
Subject Re: pg_stats explained ... ?
Date
Msg-id 28939.1013616400@sss.pgh.pa.us
Whole thread Raw
In response to pg_stats explained ... ?  ("Marc G. Fournier" <scrappy@hub.org>)
List pgsql-hackers
"Marc G. Fournier" <scrappy@hub.org> writes:
> n_distinct, I'm taking it, of -1 means its a UNIQUE INDEX, and the
> positive numbers are exact #'s ... but, -0.976321? :)

"Almost unique", evidently.  See stadistinct at
http://www.ca.postgresql.org/users-lounge/docs/7.2/postgres/catalog-pg-statistic.html

> Also, how is the avg_width interpreted?

Just what you'd expect: average stored width, in bytes, of non-NULL
entries in the column.
        regards, tom lane


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