BUG #4084: Some DST timezones switche to summer time (one week) later

The following bug has been logged online:

Bug reference:      4084
Logged by:          Premysl Paska
Email address:      premek.paska@gmail.com
PostgreSQL version: 8.0.15
Operating system:   Linux
Description:        Some DST timezones switche to summer time (one week)
later
Details:

We use TIMESTAPM WITH TIMEZONE to insert datetime values into our DB. The
problem is with the CEST timezone (Central European Summer Time; Prague) and
possibly some others.

The summer time started on 2008-03-30 02:00 in the CEST timezone shifting
offset with respect to UTC from +1 to +2. But PostgreSQL kept inserting with
the former +1 offset after this day. We tested it for various other dates
and realized that it switches to the summer time one week later
(2008-04-06).

The same problem was reported with a North American  timezone.

(BTW we have another problem with TZ, after we change TZ in the system, we
must restart Postgres to apply it also to the DB.)