Robert Haas 44f7afba79 Improve documentation of timestamp internal representation.
Be more clear that we represent timestamps in microseconds when
integer timestamps are used, and in fractional seconds when
floating-point timestamps are used.

Discussion: http://postgr.es/m/20161212135045.GB15488@e733.localdomain

Report by Alexander Alekseev.  Wording by me with a suggestion
from Tom Lane.
2017-01-04 16:30:16 -05:00
..
2016-08-15 13:49:49 -04:00