Sorry if I already reported this, I didn't see it in my feed.
Anyway, if the box you are connecting to (that has the Postgres server
on it) becomes "unresponsive" (i.e. stops sending or receiving any
network packets) then a call to isValid(5) can *hang forever*
temporary work around is to set a socketTimeout but it's not my
preferred option, since I'd have anticipated "isValid" to have timed
out after 5s.
FWIW.
More info available upon demand.
Cheers!
-Roger-