On 29 September 2015 at 13:20, Jeremy Harris <j...@wizmail.org> wrote:
> On 27/09/15 21:58, Gavin Wahl wrote: > > Somewhat harder but still possible would be using BRIN indexes to > > accelerate ORDER BY. This would require a sorting algorithm that can take > > advantage of mostly-sorted inputs. You would sort the page ranges by > their > > minimum or maximum value, then feed the sorting algorithm in that order. > > An internal merge sort does well with partially-sorted input. > Yes, the $SUBJECT would be a valid use for BRIN. And also in general for sorts, leading to an optimization of merge joins using BRIN indexes. All this was foreseen in the original design; if it really was trivial it would be in 9.5 already... -- Simon Riggs http://www.2ndQuadrant.com/ <http://www.2ndquadrant.com/> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
