On Tue, Dec 15, 2015 at 11:30 PM, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com
> wrote:
>
> Attached is a spreadsheet with results for various work_mem values, and
> also with a smaller data set (just 30M rows in the fact table), which
> easily fits into memory. Yet it shows similar gains, shaving off ~40% in
> the best case, suggesting that this is not just thanks to reduction of I/O
> when forcing the temp files to disk.
A neat idea! Have you possibly tried to also collect statistics about
actual false-positive rates and filter allocation sizes in every of the
collected data points?
--
Alex