Re: ANALYZE sampling is too good

On 11 December 2013 00:28, Greg Stark <stark@mit.edu> wrote:
>    On Wed, Dec 11, 2013 at 12:14 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
>> Block sampling, with parameter to specify sample size. +1
>
> Simon this is very frustrating. Can you define "block sampling"?

Blocks selected using Vitter's algorithm, using a parameterised
fraction of the total.

When we select a block we should read all rows on that block, to help
identify the extent of clustering within the data.

-- Simon Riggs                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services