Re: "Bug" in statistics for v7.2?

From: "Marc G(dot) Fournier" <scrappy(at)hub(dot)org>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: "Bug" in statistics for v7.2?
Date: 2002-02-13 16:15:46
Message-ID: 20020213121458.H19107-100000@mail1.hub.org
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That explains it ...

profiles_faith | count
----------------+--------
0 | 485938
1 | 2
2 | 6
7 | 2
8 | 21
(5 rows)

Cool, another waste of space *sigh*

thanks ...

On Wed, 13 Feb 2002, Tom Lane wrote:

> "Marc G. Fournier" <scrappy(at)hub(dot)org> writes:
> > Okay, if I'm understanding pg_stats at all, which I may not be, n_distinct
> > should represent # of distinct values in that row, no?
> > But, I have one field that has 5 distinct values:
> > But pg_stats is reporting 1:
>
> The pg_stats values are only, um, statistical. If 99.9% of the table is
> the same value and the other four values appear only once or twice, it's
> certainly possible for ANALYZE's sample to include only the common value
> and miss the rare ones. AFAIK that will not break anything; if you have
> an example where the planner seems to be fooled because of this, let's
> see it.
>
> regards, tom lane
>

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