Horton

Re: Need a mentor, and a project.

Robert Haas <robertmhaas@gmail.com>

View thread View on postgr.es
From: Robert Haas <robertmhaas@gmail.com>
To: Bruce Momjian <bruce@momjian.us>
Cc: Ashish <abindra@u.washington.edu>, Josh Berkus <josh@agliodbs.com>, Joshua Tolley <eggyknap@gmail.com>, Albe Laurenz <laurenz.albe@wien.gv.at>, pgsql-hackers@postgresql.org
Date: 2009-12-12T02:30:20Z
Lists: pgsql-hackers 
On Fri, Dec 11, 2009 at 9:05 PM, Bruce Momjian <bruce@momjian.us> wrote:
> Ashish wrote:
>> I am thinking about starting with the following TODO item:
>>
>> --> Have EXPLAIN ANALYZE issue NOTICE messages when the estimated
>> and actual row counts differ by a specified percentage.
>>
>> I picked this because it is somewhat related to query processing
>> which is what I am most interested in. It also <seems> like a
>> good start up project for a newbie like me. Before I start
>> looking into what this would involve and start a conversation
>> on designing a solution - I wanted to know what you guys think
>> about this particular TODO, and it suitability to a newbie.
>> Looking forward to your comments...
>
> I even have a sample patch you can use as a start, attached.

Interesting.  The logic in ExplainVariance() doesn't look right to me
- the cases where one argument is zero seem like they will produce a
differently-scaled result than otherwise.

...Robert