This one-line change provoked a lot of discussion, but ultimately
the consensus seems to be that allowing a larger value might be
useful to somebody, and probably won't hurt anyone who chooses
not to take advantage of the higher maximum limit.
Vyacheslav Makarov, reviewed by many people.
Discussion: http://postgr.es/m/7b5ecc5a9991045e2f13c84e3047541d@postgrespro.ru