Thread: Benchmarking
I need to check the scalability of a machine with postgresql and Im doing it with pgbench but Im getting values with a variation of a 40% with the same pgbench call... Just the same variation if I restart posgresql or overwrite the db... So just wondering if theres another benchmarking tool for postgres... Perhaps should I write my own one?
> I need to check the scalability of a machine with postgresql and Im doing it > with pgbench but Im getting values with a variation of a 40% with the same > pgbench call... You might be looking at the effect of the kernel buffer cache. Try run pgbench several times with same settings. Another point is how many transactions pgbench runs (-t option). More transactions would give more statble results. Here is my small script to run pgbench. I usually run it 2 or 3 times and take only the last run result. #! /bin/sh pgbench -i -s 2 test for i in 1 2 4 8 16 32 64 128 dot=`expr 640 / $i`pgbench -t $t -c $i testecho "===== sync ======"sync;sync;sync;sleep 10echo "===== sync done ======" done