Hannu Krosing <hannu@tm.ee> writes:
> Have you any ideas how to distinguish between interactive and
> non-interactive disk I/O coming from postgresql backends ?
I don't see how. For one thing, the backend that originally dirtied
a buffer is not necessarily the one that writes it out. Even assuming
that we could assign a useful priority to different I/O requests,
how do we tell the kernel about it? There's no portable API for that
AFAIK.
One thing that would likely help a great deal is to have the WAL files
on a separate disk spindle, but since what I've got is a one-disk
system, I can't test that on this PC.
regards, tom lane