Periodic scripts that hit external servers can cause a "thundering herd" problem, whereby many systems' periodic scripts run at the same time, and overload the server. To prevent this, such scripts should sleep for a random amount of time before hitting the external server.
After r316432, there is a common anticongestion function to handle this. For an example of how to use it, see
Please create a diff.
I don't use pwhois myself. I just found the problem by grepping, after I had noticed it in a different port. So I don't have a diff for the pwhois port. See the link below for an example of how I fixed it in bsdstats.
Created attachment 189573 [details]