Andres Freund <and...@2ndquadrant.com> writes: > On 2014-12-24 00:27:39 -0600, Jim Nasby wrote: >> pgbench -S -T10 -c 4 -j 4 >> master: >> tps = 9556.356145 (excluding connections establishing) >> tps = 9897.324917 (excluding connections establishing) >> tps = 9287.286907 (excluding connections establishing) >> tps = 10210.130833 (excluding connections establishing) >> >> XXH32: >> tps = 32462.754437 (excluding connections establishing) >> tps = 33232.144511 (excluding connections establishing) >> tps = 33082.436760 (excluding connections establishing) >> tps = 33597.904532 (excluding connections establishing)
> FWIW, I don't believe these results for one second. It's quite plausible > that there's a noticeable performance benefit, but a factor of three is > completely unrealistic... Could you please recheck? A possible theory is that the hash change moved some locks into different partitions causing a large reduction in contention, but even then 3X seems unlikely. And of course if that was the mechanism, the result is still pure luck; other examples might get worse by the same amount. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers