Josh berkus <josh(at)agliodbs(dot)com> writes:
> Is there a thread on how we determined this default of 2? I can't find
> one under likely search terms.
The 9.6 open-items list cites
https://www.postgresql.org/message-id/flat/20160420174631(dot)3qjjhpwsvvx5bau5(at)alap3(dot)anarazel(dot)de
regards, tom lane