It seems that time-based GUC variables can be spelled like1h but not 1hr1min but not 1m1s but
not 1sec
This is inconsistent and confusing. I don't object to the ones on the
left as being the standard spellings for printout, but if we're not
going to have a simple uniform rule like "shortest possible
abbreviation" then we ought to accept plausible alternatives on input.
I got burnt by this just now because I looked at the autovacuum_naptime
setting in postgresql.conf, which is shown as '1min', and figured I
could change it to '5sec'.
regards, tom lane