anything conclusive, other than fork confuses mysqld, and our attempt
to unconfuse it by closing/opening the DB connection in the child,
confuses it even more! The parent connection is shutdown and then
restarted as well. In node_reboot, this could happen 10 times in rapid
succession as we fork as child for each node, and that appears to
strain the server even more (with 20 rapid connects).

So, I added a select(0.3) in TBdbfork() (in the child) to see if that
slows things down enough. In my tests, the length of time between the
parent and child operations makes a real difference. With a delay in
the child, the parent connection is not closed/restarted.

The astute reader will realize that I have no actual clue; just
grasping at, uh, threads.