initdb profiles

One regular topic of conversation on IRC and elsewhere is that the
settings initdb installs especially for memory use, connections, and so
on, are often very conservative. Of course, we tell people how to tune
them to some extent, although performance tuning seems to remain a black
art. But I wondered if it might not be a good idea to allow an option to
initdb which would provide a greater possible range of settings for
max_connections, shared_buffers and so on. For example, we might offer a
profile which is very conservative for memory bound machines, medium
size for a development platform, large for a server running with other
server processes, and huge for a decdicated box, and then provide some
heuristics that initdb could apply. We'd have to let all of these
degrade nicely, so that even if the user select the machine hog setting,
if we find we can only do something like the tiny setting that's what
s/he would get. Also, we might need to have some tolerably portable way
of finding out about machine resources. And power users will still want
to tube things more. But it might help to alleviate our undeserved
reputation for poor performance if we provide some help to start off at
least in the right ballpark.

thoughts?

cheers

andrew