Teodor Sigaev <teo...@sigaev.ru> writes: > Yep, for now on my notebook (best from 5 tries): > % pgbench -i -s 3000 > % pgbench -s 3000 -c 4 -j 4 -P 1 -T 60 > HEAD 569 tps > patched 542 tps > % pgbench -s 3000 -c 4 -j 4 -P 1 -T 60 -S > HEAD 9500 tps > patched 9458 tps
> Looks close to measurement error, but may be explained increased amount > of work for planning. Including, may be, more complicated path tree. Hmmm ... I'm now wondering about the "measurement error" theory. I tried to repeat this measurement locally, focusing on the select-only number since that should have a higher ratio of planning time to execution. Test setup: cassert-off build pgbench -i -s 100 sudo cpupower frequency-set --governor performance repeat 3 times: pgbench -c 4 -j 4 -P 5 -T 60 -S HEAD: tps = 32508.217002 (excluding connections establishing) tps = 33081.402766 tps = 32520.859913 average of 3: 32703 tps WITH PATCH: tps = 32815.922160 (excluding connections establishing) tps = 33312.149718 tps = 32784.527489 average of 3: 32970 tps (Hardware: dual quad-core Xeon E5-2609, running current RHEL6) So I see no evidence for a slowdown on pgbench's SELECT queries. Anybody else want to check performance on simple scan/join queries? 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