Re: performance "tests"

Raphael Bauduin <raphael(at)be(dot)easynet(dot)net> writes:
> At some times, it seems to hang: it doesn't insert any rows for more
> than 10 seconds. At that time, the postmaster process takes 0%. Why is
> that?

At a guess, you're seeing the syncer daemon flushing a lot of dirty
kernel disk buffers out to disk, and thereby monopolizing disk I/O.
I haven't experimented too much with Linux, but on HPUX it's not
difficult for a sync() call to bring the system to its knees for many
seconds, if you've got application programs that have written a whole
lot of pages since the last sync.

> What's strange is that everything else hangs also! Would that be due
> to the CPU??

The CPU is free, but everything that wants to access disk is starved
for disk bandwidth ...

> ii postgresql 7.1.3-7 Object-relational SQL database, descended fr

If you're going to run tests on foreign-key performance, please use
7.2.*.

regards, tom lane