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Convert explanation of interval change into something resembling grammatical

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English, and fix the incorrect example.
This commit is contained in:
Tom Lane 2005-10-25 17:54:30 +00:00
parent 6a9b93a0e1
commit 602007842c
1 changed files with 13 additions and 12 deletions
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25
doc/src/sgml/release.sgml
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@ -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>