so, does this overlap or not...? - fencepost question on overlaps()

Hi,

This doesn't seem to make sense to me, can someone explain the rationale
behind it?

postgres=# select version();
version
---------------------------------------------------------------------------------------
PostgreSQL 8.4.4 on x86_64-unknown-linux-gnu, compiled by GCC gcc (GCC)
4.3.3, 64-bit
(1 row)

Range 1 ending on date A does not overlap with range 2 starting on date A:

postgres=# select ('2010-01-01'::date, '2010-01-05'::date) overlaps
('2010-01-05'::date, '2010-01-10'::date);
overlaps
----------
f
(1 row)

But it does when range 1 is only a single day:

postgres=# select ('2010-01-05'::date, '2010-01-05'::date) overlaps
('2010-01-05'::date, '2010-01-10'::date);
overlaps
----------
t
(1 row)

BTW, it doesn't matter whether one casts to date or timestamp

--
Best,

Frank.