Re: Macros for time magic values

Alvaro Herrera wrote:
> Excerpts from Tom Lane's message of mar mar 15 11:42:06 -0300 2011:
> > "Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
> > > Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > >> Dimitri Fontaine <dimitri@2ndQuadrant.fr> writes:
> > >>> Would it help moving toward Leap Second support, and is this
> > >>> something we want to have?
> >
> > >> IMO we don't want to have that, as it would completely bollix
> > >> datetime calculations of all kinds.  You couldn't even count on
> > >> stored timestamps not changing their meaning.
> >
> > > I'm inclined to agree, but if that's the choice, should we stop
> > > claiming that we're using UTC, and instead claim UT1 support?  It
> > > always seemed a little odd to me that the docs say UTC but there's
> > > no actual support for leap seconds in calculations.
> >
> > Maybe, but if the docs started talking about that, we'd have to define
> > the term every time.  The number of PG users who know what UT1 is can
> > probably be counted without running out of toes.
>
> A small note somewhere visible would suffice: "these docs talk about UTC
> but they really mean UT1 because we have no leap seconds support".

Done with the attached doc patch, backpatched to 9.1.

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
new file mode 100644
index 6d5dad3..d6baf84
*** a/doc/src/sgml/catalogs.sgml
--- b/doc/src/sgml/catalogs.sgml
***************
*** 8341,8347 ****
     The view <structname>pg_timezone_names</structname> provides a list
     of time zone names that are recognized by <command>SET TIMEZONE</>,
     along with their associated abbreviations, UTC offsets,
!    and daylight-savings status.
     Unlike the abbreviations shown in <link
     linkend="view-pg-timezone-abbrevs"><structname>pg_timezone_abbrevs</structname></link>, many of these names imply
aset of daylight-savings transition 
     date rules.  Therefore, the associated information changes across local DST
--- 8341,8349 ----
     The view <structname>pg_timezone_names</structname> provides a list
     of time zone names that are recognized by <command>SET TIMEZONE</>,
     along with their associated abbreviations, UTC offsets,
!    and daylight-savings status.  (Technically,
!    <productname>PostgreSQL</productname> uses <acronym>UT1</> rather
!    than UTC because leap seconds are not handled.)
     Unlike the abbreviations shown in <link
     linkend="view-pg-timezone-abbrevs"><structname>pg_timezone_abbrevs</structname></link>, many of these names imply
aset of daylight-savings transition 
     date rules.  Therefore, the associated information changes across local DST
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
new file mode 100644
index 4c3e232..c03dd6c
*** a/doc/src/sgml/func.sgml
--- b/doc/src/sgml/func.sgml
*************** SELECT EXTRACT(SECOND FROM TIME '17:12:2
*** 6898,6904 ****
         <para>
          The time zone offset from UTC, measured in seconds.  Positive values
          correspond to time zones east of UTC, negative values to
!         zones west of UTC.
         </para>
        </listitem>
       </varlistentry>
--- 6898,6906 ----
         <para>
          The time zone offset from UTC, measured in seconds.  Positive values
          correspond to time zones east of UTC, negative values to
!         zones west of UTC.  (Technically,
!         <productname>PostgreSQL</productname> uses <acronym>UT1</> because
!         leap seconds are not handled.)
         </para>
        </listitem>
       </varlistentry>