On Mon, Mar 27, 2017 at 04:29:56PM -0400, Robert Haas wrote: > On Thu, Mar 23, 2017 at 2:47 PM, Pavan Deolasee > <pavan.deola...@gmail.com> wrote: > > It's quite hard to say that until we see many more benchmarks. As author of > > the patch, I might have got repetitive with my benchmarks. But I've seen > > over 50% improvement in TPS even without chain conversion (6 indexes on a 12 > > column table test). > > This seems quite mystifying. What can account for such a large > performance difference in such a pessimal scenario? It seems to me > that without chain conversion, WARM can only apply to each row once > and therefore no sustained performance improvement should be possible > -- unless rows are regularly being moved to new blocks, in which case > those updates would "reset" the ability to again perform an update. > However, one would hope that most updates get done within a single > block, so that the row-moves-to-new-block case wouldn't happen very > often. > > I'm perplexed.
Yes, I asked the same question in this email: https://www.postgresql.org/message-id/20170321190000.ge16...@momjian.us -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + As you are, so once was I. As I am, so you will be. + + Ancient Roman grave inscription + -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers