On Fri, Nov 20, 2015 at 2:58 PM, Peter Geoghegan <pg@heroku.com> wrote:
> The numbers speak for themselves here. I just want to be clear about
> the disadvantages of what I propose, even if it's well worth it
> overall in most (all?) cases.
There is a paper called "Critical Evaluation of Existing External
Sorting Methods in the Perspective of Modern Hardware":
http://ceur-ws.org/Vol-1343/paper8.pdf
This paper was not especially influential, and I don't agree with
every detail, or I at least don't think that every recommendation
should be adopted to Postgres. Even still, the paper is the best
summary I have seen so far. It clearly explains why there is plenty to
recommend a simple hybrid sort-merge strategy over replacement
selection, despite the fact that replacement selection is faster when
using 1970s hardware.
--
Peter Geoghegan