postgres.git / summary / log / commit / refs
commit 9a8b1b6777178c76c48043c3d7bfbe911d2ee577
Author: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon Jan 10 16:46:16 2022 +0000
First released in: 15.0, 10.20, 11.15, 12.10, 13.6, 14.2
Doc: fix bogus example about ambiguous timestamps.
I had a brain fade in commit d32899157, and used 2:30AM as the
example timestamp for both spring-forward and fall-back cases.
But it's not actually ambiguous at all in the fall-back case,
because that transition is from 2AM to 1AM under USA rules.
Fix the example to use 1:30AM, which *is* ambiguous.
Noted while answering a question from Aleksander Alekseev.
Back-patch to all supported branches.
Discussion: https://postgr.es/m/2191355.1641828552@sss.pgh.pa.us
doc/src/sgml/datetime.sgml | 20 +++++++++-----------
1 file changed, 9 insertions(+), 11 deletions(-)
diff --git a/doc/src/sgml/datetime.sgml b/doc/src/sgml/datetime.sgml
index dec64a51387..f0904eeaa56 100644
--- a/doc/src/sgml/datetime.sgml
+++ b/doc/src/sgml/datetime.sgml
@@ -210,27 +210,25 @@
<para>
Conversely, consider the behavior during a fall-back transition:
<programlisting>
-=> SELECT '2018-11-04 02:30'::timestamptz;
+=> SELECT '2018-11-04 01:30'::timestamptz;
timestamptz
------------------------
- 2018-11-04 02:30:00-05
+ 2018-11-04 01:30:00-05
(1 row)
</programlisting>
- On that date, there were two possible interpretations of 2:30AM; there
- was 2:30AM EDT, and then an hour later after the reversion to standard
- time, there was 2:30AM EST.
+ On that date, there were two possible interpretations of 1:30AM; there
+ was 1:30AM EDT, and then an hour later after clocks jumped back from
+ 2AM EDT to 1AM EST, there was 1:30AM EST.
Again, <productname>PostgreSQL</productname> interprets the given time
- as if it were standard time (UTC-5). We can force the matter by
- specifying daylight-savings time:
+ as if it were standard time (UTC-5). We can force the other
+ interpretation by specifying daylight-savings time:
<programlisting>
-=> SELECT '2018-11-04 02:30 EDT'::timestamptz;
+=> SELECT '2018-11-04 01:30 EDT'::timestamptz;
timestamptz
------------------------
- 2018-11-04 01:30:00-05
+ 2018-11-04 01:30:00-04
(1 row)
</programlisting>
- This timestamp could validly be rendered as either 2:30 UTC-4 or
- 1:30 UTC-5; the timestamp output code chooses the latter.
</para>
<para>
[parent: ab3764a417ff]