Re: hist boundary duplicates bug in head and 8.3

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Nathan Boley" <npboley(at)gmail(dot)com>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: hist boundary duplicates bug in head and 8.3
Date: 2009-01-06 22:30:11
Message-ID: 12448.1231281011@sss.pgh.pa.us
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"Nathan Boley" <npboley(at)gmail(dot)com> writes:
> For heavy tailed distributions, it is possible for analyze to
> duplicate histogram boundaries.

I don't think this is a bug. You've got values that didn't make it into
the MCV list, but nonetheless occupy multiple buckets' worth of space in
the remainder of the distribution. They *should* appear multiple times
in the histogram. If they didn't, the histogram would be understating
their frequency.

regards, tom lane

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