On 03/16/2018 09:47 AM, Alexander Korotkov wrote: > On Fri, Mar 16, 2018 at 5:12 AM, Tomas Vondra > <tomas.von...@2ndquadrant.com <mailto:tomas.von...@2ndquadrant.com>> wrote: > > I agree those don't seem like an issue in the Incremental Sort patch, > but like a more generic costing problems. > > > Yes, I think so too.
I wonder if we could make the costing a bit more pessimistic, to make these loses less likely, while still keeping the main wins (particularly for the LIMIT queries). But that seems a bit like a lost case, I guess. > Do you think we can mark this patch RFC assuming that it have > already got pretty much of review previously. > Actually, I was going to propose to switch it to RFC, so I've just done that. I think the patch is clearly ready for a committer to take a closer look. I really like this improvement. I'm going to rerun the tests, but that's mostly because I'm interested if the change from i++ to i-- in cmpSortPresortedCols makes a measurable difference. I don't expect to find any issues, so why wait with the RFC? regards -- Tomas Vondra http://www.2ndQuadrant.com PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
