diff --git a/doc/src/sgml/release.sgml b/doc/src/sgml/release.sgml index fa05a7e2f4f45ef206b291d53e906533329e4c20..0a5a1098efc1c27286e2468159cae2399812c72b 100644 --- a/doc/src/sgml/release.sgml +++ b/doc/src/sgml/release.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/release.sgml,v 1.392 2005/10/25 15:12:22 momjian Exp $ +$PostgreSQL: pgsql/doc/src/sgml/release.sgml,v 1.393 2005/10/25 17:54:30 tgl Exp $ Typical markup: @@ -1147,7 +1147,7 @@ psql -t -f fixseq.sql db1 | psql -e db1 SELECT CURRENT_TIMESTAMP AT TIME ZONE 'Europe/London'; </programlisting> In the above query, the time zone used is adjusted based on the - daylight savings time rules that were in effect on the supplied + daylight saving time rules that were in effect on the supplied date. </para> </listitem> @@ -1206,21 +1206,22 @@ psql -t -f fixseq.sql db1 | psql -e db1 <listitem> <para> - Add an internal day field to <type>INTERVAL</> so a one day + Add a separate day field to type <type>interval</> so a one day interval can be distinguished from a 24 hour interval (Michael Glaesemann) </para> <para> - Dates that contain a daylight savings time adjustment are not 24 - hours, but typically 23 or 25 hours. This change allows numeric days - (not fixed 24-hour periods) to be added to dates which include - a daylight savings time adjustment period. Therefore, while in - previous releases <literal>1 day</> and <literal>24 hours</> were - interchangeable interval values, in this release they are treated - differently, e.g. + Days that contain a daylight saving time adjustment are not 24 + hours long, but typically 23 or 25 hours. This change creates a + conceptual distinction between intervals of <quote>so many days</> + and intervals of <quote>so many hours</>. Adding + <literal>1 day</> to a timestamp now gives the same local time on + the next day even if a daylight saving time adjustment occurs + between, whereas adding <literal>24 hours</> will give a different + local time when this happens. For example, under US DST rules: <programlisting> - '2005-05-03 00:00:00 EST' + '1 day' = '2005-05-04 00:00:00-04' - '2005-05-03 00:00:00 EST' + '24 hours' = '2005-05-04 01:00:00-04' + '2005-04-03 00:00:00-05' + '1 day' = '2005-04-04 00:00:00-04' + '2005-04-03 00:00:00-05' + '24 hours' = '2005-04-04 01:00:00-04' </programlisting> </para> </listitem>