Re: Date/Time Types : internals

On Wed, Apr 18, 2012 at 4:14 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> "Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
>> I guess the point is that for hundreds of years, the same day could
>> have a different date depending which country's calendar you were
>> looking at.  I'm not entirely clear why there's a problem if you
>> pick the Gregorian calendar and apply it retroactively.
>
> Which is, in fact, exactly what our code does.  I think that bit in the
> docs is trying to explain why we do that rather than try to get the
> code to reflect what people really used back then.

What I find a bit confusing is that this part talks about the Julian
calendar, but elsewhere:

  <para>
   The SQL standard states that <quote>Within the definition of a
   <quote>datetime literal</quote>, the <quote>datetime
   value</quote>s are constrained by the natural rules for dates and
   times according to the Gregorian calendar</quote>.  Dates between
   1582-10-05 and 1582-10-14, although eliminated in some countries
   by Papal fiat, conform to <quote>natural rules</quote> and are
   hence valid dates.  <productname>PostgreSQL</> follows the SQL
   standard's lead by counting dates exclusively in the Gregorian
   calendar, even for years before that calendar was in use.
  </para>

So which calendar are we using, Julian or Gregorian?

--
Robert Haas
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