Re: First set of OSDL Shared Mem scalability results, some

Curt Sampson <cjs(at)cynic(dot)net> writes:
> I see the OS issues related to mapping that much memory as a much bigger
> potential problem.

I see potential problems everywhere I look ;-)

Considering that the available numbers suggest we could win just a few
percent (and that's assuming that all this extra mechanism has zero
cost), I can't believe that the project is worth spending manpower on.
There is a lot of much more attractive fruit hanging at lower levels.
The bitmap-indexing stuff that was recently being discussed, for
instance, would certainly take less effort than this; it would create
no new portability issues; and at least for the queries where it helps,
it could offer integer-multiple speedups, not percentage points.

My engineering professors taught me that you put large effort where you
have a chance at large rewards. Converting PG to mmap doesn't seem to
meet that test, even if I believed it would work.

regards, tom lane