On Tue, Dec 10, 2013 at 10:34 PM, Simon Riggs <si...@2ndquadrant.com> wrote: > On 11 December 2013 01:27, Sergey E. Koposov <m...@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 -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
