Re: XLogInsert scaling, revisited

Heikki Linnakangas <hlinnakangas@vmware.com> writes:
> I've been slowly continuing to work that I started last winder to make 
> XLogInsert scale better. I have tried quite a few different approaches 
> since then, and have settled on the attached. This is similar but not 
> exactly the same as what I did in the patches I posted earlier.

This sounds pretty good.  I'm a bit bothered by the fact that you've
settled on 7 parallel-insertion slots after testing on an 8-core
machine.  I suspect that it's not a coincidence that you're seeing
a sweet spot for #slots ~= #CPUs.  If that is what's happening, we're
going to want to be able to configure the #slots at postmaster start.
Not sure how we'd go about it exactly - is there any reasonably portable
way to find out how many CPUs the machine has?  Or do we have to use a
GUC for that?

			regards, tom lane