Re: ANALYZE sampling is too good

On 10 December 2013 19:54, Josh Berkus <josh@agliodbs.com> wrote:
> On 12/10/2013 11:49 AM, Peter Geoghegan wrote:
>> On Tue, Dec 10, 2013 at 11:23 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
>> I don't think that anyone believes that not doing block sampling is
>> tenable, fwiw. Clearly some type of block sampling would be preferable
>> for most or all purposes.
>
> As discussed, we need math though.  Does anyone have an ACM subscription
> and time to do a search?  Someone must.  We can buy one with community
> funds, but no reason to do so if we don't have to.

We already have that, just use Vitter's algorithm at the block level
rather than the row level.

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