On Fri, Feb 20, 2015 at 3:57 PM, Tomas Vondra <tomas.von...@2ndquadrant.com> wrote: > I've spent a fair amount of testing this today, and when using the > simple percentile_disc example mentioned above, I see this pattern: > > master patched speedup > --------------------------------------------------------- > generate_series(1,1000000) 4.2 0.7 6 > generate_series(1,2000000) 9.2 9.8 0.93 > generate_series(1,3000000) 14.5 15.3 0.95 > > > so for a small dataset the speedup is very nice, but for larger sets > there's ~5% slowdown. Is this expected?
I had a look at this patch today with a view to committing it, but it seems that nobody's commented on this point, which seems like an important one. Any thoughts? For what it's worth, and without wishing to provoke another flamewar, I am inclined to use Andrew's version of this patch rather than Peter's. I have not undertaken an exhaustive comparison, nor do I intend to. It is the reviewer's responsibility to justify the changes they think the author needs to make, and that wasn't done here. On the points of difference Andrew highlighted, I think his version is fine. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
