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Message-Id: <B8F900A1-1ACB-4C84-84D6-676B2B7DF8A2@gmail.com>
From: Robert Haas <robertmhaas@gmail.com>
To: Simon Riggs <simon@2ndQuadrant.com>
In-Reply-To: <1243950060.23910.58.camel@ebony.2ndQuadrant>
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Subject: Re: explain analyze rows=%.0f
Date: Tue, 2 Jun 2009 10:06:18 -0400
Cc: Ron Mayer <rm_pg@cheapcomplexdevices.com>,
	Euler Taveira de Oliveira <euler@timbira.com>,
	"pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>

On Jun 2, 2009, at 9:41 AM, Simon Riggs <simon@2ndQuadrant.com> wrote:

>
> On Mon, 2009-06-01 at 20:30 -0700, Ron Mayer wrote:
>
>> What I'd find strange about "6.67 rows" in your example is more  
>> that on
>> the estimated rows side, it seems to imply an unrealistically  
>> precise estimate
>> in the same way that "667 rows" would seem unrealistically precise  
>> to me.
>> Maybe rounding to 2 significant digits would reduce confusion?
>
> You're right that the number of significant digits already exceeds the
> true accuracy of the computation. I think what Robert wants to see is
> the exact value used in the calc, so the estimates can be checked more
> thoroughly than is currently possible.

Bingo.

...Robert