Per request from Qingqing, here is the version of pgbench I made up to
drive each backend from a separately forked subprocess. This is not
meant for application, at least not yet, since it won't work on Windows,
and there are performance issues to be resolved anyway. (If we figure
out the performance problem, we could probably adapt it for Windows by
#ifdef'ing to use threads instead of fork().)
regards, tom lane