There is a subtle problem when one does a cast with `::date`. Observe:
teststorj=# set timezone = 'US/Eastern';
SET
teststorj=# select (timestamp with time zone '2020-02-01 00:00:00+00')::date;
date
------------
2020-01-31
(1 row)
teststorj=# set timezone = 'UTC';
SET
teststorj=# select (timestamp with time zone '2020-02-01 00:00:00+00')::date;
date
------------
2020-02-01
(1 row)
In order to correctly determine the date a timestamp is in, one has to
explicitly pick the time zone that the date truncation should use
otherwise postgres will use whatever setting the client has. These
tests were failing for me locally, because I run my postgres in
the US/Eastern time zone to try to tickle these bugs out. So it
should be `(x at time zone 'UTC')::date` instead of just `x::date`.
Change-Id: I4e9e32d4b53abc6165a4d0474f4702f8b9f801c7
6352d46100