On Dec 26, 2007 4:41 PM, Guillaume Smet <guillaume.smet@gmail.com> 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