On Dec 26, 2007 4:41 PM, Guillaume Smet <guillaume.smet@xxxxxxxxx> wrote: > Then I decided to perform read-only tests using -S option (pgbench -S > -s 100 -c 16 -t 30000 -U postgres bench). And still the same > behaviour: > shared_buffers=64MB : 20k tps > shared_buffers=1024MB : 8k tps Some more information. If I strace the backends during the test, the test is faster with shared_buffers=1024MB and I have less system calls (less read and less lseek). A quick cut | uniq | sort gives me: With 64MB: 12548 semop 160039 sendto 160056 recvfrom 294289 read 613338 lseek With 1024MB: 11396 semop 129947 read 160039 sendto 160056 recvfrom 449584 lseek -- Guillaume ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
