Re: 8.4 open item: copy performance regression?

"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
> The checkpoint_segments seems dramatic enough to be real.  I wonder if
> the test is short enough that it never got around to re-using any of
> them, so it was doing extra writes for the initial creation during the
> test?

That's exactly what I was about to suggest.  Are you starting each run
from a fresh initdb?  If so, try running the load long enough that the
number of WAL files stabilizes (should happen at 2x checkpoint_segments)
and then start the test measurement.
        regards, tom lane