"Schmidt, Peter" <peter.schmidt@prismedia.com> writes:
> I tried -B 1024 and got roughly the same results (~50 tps).
What were you using before?
> However, when I change WAL option commit_delay from the default of 5
> to 0, I get ~200 tps (which is double what I get with 7.03). I'm not
> sure I want to do this, do I?
Hmm. There have been several discussions about whether CommitDelay is
a good idea or not. What happens if you vary it --- try 1 microsecond,
and then various multiples of 1000. I suspect you may find that there
is no difference in the range 1..10000, then a step, then no change up
to 20000. In other words, your kernel may be rounding the delay up to
the next multiple of a clock tick, which might be 10 milliseconds.
That would explain a 50-tps limit real well...
BTW, have you tried pgbench with multiple clients (-c) rather than just
one?
regards, tom lane