Re: ANALYZE sampling is too good - Mailing list pgsql-hackers

From Hannu Krosing
Subject Re: ANALYZE sampling is too good
Date
Msg-id 52A81941.1080704@2ndQuadrant.com
Whole thread Raw
In response to Re: ANALYZE sampling is too good  (Greg Stark <stark@mit.edu>)
List pgsql-hackers
On 12/11/2013 01:44 AM, Greg Stark wrote:
> On Wed, Dec 11, 2013 at 12:40 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
>> When we select a block we should read all rows on that block, to help
>> identify the extent of clustering within the data.
> So how do you interpret the results of the sample read that way that
> doesn't introduce bias?
>
Initially/experimentally we could just compare it to our current approach :)

That is, implement *some* block sampling and then check it against what
we currently have. Then figure out the bad differences. Rinse. Repeat.

Cheers

-- 
Hannu Krosing
PostgreSQL Consultant
Performance, Scalability and High Availability
2ndQuadrant Nordic OÜ




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