On Tue, Dec 10, 2013 at 10:34 PM, Simon Riggs <simon@2ndquadrant.com> wrote:
> On 11 December 2013 01:27, Sergey E. Koposov <math@sai.msu.ru> wrote:
>> For what it's worth.
>>
>> I'll quote Chaudhuri et al. first line from the abstract about the block
>> sampling.
>> "Block-level sampling is far more efficient than true uniform-random
>> sampling over a large database, but prone to significant errors if used to
>> create database statistics."
>
> This glosses over the point that both SQLServer and Oracle use this technique.
That seems like an unusual omission for Microsoft Research to have made.
I didn't read that paper, because undoubtedly it's all patented. But
before I figured that out, after finding it on Google randomly, I did
read the first couple of paragraphs, which more or less said "what
follows - the entire paper - is an explanation as to why it's okay
that we do block sampling".
--
Peter Geoghegan