Alfranio Correia Junior <alfranio@lsd.di.uminho.pt> writes:
> I am facing a problem trying to put 500 concurrent users accessing
> a postgresql instance.
I think you're going to need to buy more RAM. 1Gb of RAM means there
is a maximum of 2Mb available per Postgres process before you start
to go into swap hell --- in practice a lot less, since you have to allow
for other things like the kernel and other applications.
AFAIR TPC-C doesn't involve any complex queries, so it's possible you
could run it with only 1Mb of workspace per process, but not when
you've configured
> sort_mem = 10240
That's ten times more than your configuration can possibly support.
(I don't recall whether TPC-C uses any queries that would sort, so
it's possible this setting isn't affecting you; but if you are doing
any sorts then it's killing you.)
Bottom line is you probably need more RAM.
regards, tom lane