> > I'm suspect that the previous runs were colored by having the entire
> > dataset in memory as well as the update contention.
>
> A run of vmstat while the test is in progress might well show what's affecting
> performance here.
Unfortunately, vmstat on OSX is not what it is on Linux.
vm_stat on osx gives virtual memory stats, but not disk io or cpu load.
iostat looks promising, but is a noop.
Top takes 10 % of processor.
eric