On Wed, Sep 28, 2016 at 9:10 PM, Tomas Vondra <tomas.von...@2ndquadrant.com> wrote: >> I feel like we must be missing something here. If Dilip is seeing >> huge speedups and you're seeing nothing, something is different, and >> we don't know what it is. Even if the test case is artificial, it >> ought to be the same when one of you runs it as when the other runs >> it. Right? >> > Yes, definitely - we're missing something important, I think. One difference > is that Dilip is using longer runs, but I don't think that's a problem (as I > demonstrated how stable the results are).
It's not impossible that the longer runs could matter - performance isn't necessarily stable across time during a pgbench test, and the longer the run the more CLOG pages it will fill. > I wonder what CPU model is Dilip using - I know it's x86, but not which > generation it is. I'm using E5-4620 v1 Xeon, perhaps Dilip is using a newer > model and it makes a difference (although that seems unlikely). The fact that he's using an 8-socket machine seems more likely to matter than the CPU generation, which isn't much different. Maybe Dilip should try this on a 2-socket machine and see if he sees the same kinds of results. -- 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
