AT TIME ZONE and DST in UTC<->CET conversion

[Jaromír Talíř <jaromir.talir@xxxxxx>]

First, if I do conversion from UTC to CET and back when a timestamp is
OUTSIDE of daylight saving period, it's correct:

postgres# select '2008-01-01 10:10:10 UTC' AT TIME ZONE 'CET';
      timezone      
---------------------
 2008-01-01 11:10:10

postgres# select '2008-01-01 11:10:10 CET' AT TIME ZONE 'UTC';
      timezone      
---------------------
 2008-01-01 10:10:10


When I do the same INSIDE this period just the UCT->CET direction is
correct but back direction will fail subtracting only 1 hour instead of
2 hours.

postgres# select '2008-06-01 10:10:10 UTC' AT TIME ZONE 'CET';
      timezone      
---------------------
 2008-06-01 12:10:10

postgres# select '2008-06-01 12:10:10 CET' AT TIME ZONE 'UTC';
      timezone      
---------------------
 2008-06-01 11:10:10

If it supports automatic discovery of DST in conversion from UTC to CET
(and this is great), why it doesn't support this discovery in opposit
direction?

Regards,
Jaromir

<<attachment: smime.p7s>>