Re: TO_CHAR(timestamptz,datetimeformat) wrong after DST change

"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
> "Jonathan Brinkman" <JB@BlackSkyTech.com> wrote:
>> I guess EST is not DST-friendly?

> EST stands for Eastern *Standard* Time, which is explicitly *not*
> under Daylight Saving Time.

Right.  SET TIMEZONE 'EST' gets you GMT-5 all year round.
For background see this bit in src/timezone/data/northamerica:

# From Arthur David Olson, 2005-12-19
# We generate the files specified below to guard against old files with
# obsolete information being left in the time zone binary directory.
# We limit the list to names that have appeared in previous versions of
# this time zone package.
# We do these as separate Zones rather than as Links to avoid problems if
# a particular place changes whether it observes DST.
# We put these specifications here in the northamerica file both to
# increase the chances that they'll actually get compiled and to
# avoid the need to duplicate the US rules in another file.

# Zone    NAME        GMTOFF    RULES    FORMAT    [UNTIL]
Zone    EST         -5:00    -    EST
Zone    MST         -7:00    -    MST
Zone    HST        -10:00    -    HST
Zone    EST5EDT         -5:00    US    E%sT
Zone    CST6CDT         -6:00    US    C%sT
Zone    MST7MDT         -7:00    US    M%sT
Zone    PST8PDT         -8:00    US    P%sT

(Note: the lack of a RULES entry means no DST rule.)

            regards, tom lane