Re: PDT but not WEST

On 09/29/2011 10:50 AM, Tom Lane wrote:
> Christophe Pettus<xof(at)thebuild(dot)com> writes:
>> I am baffled. Both PDT and WEST appear as valid timezone abbreviations, and each have unique values, but:
> Where do you see WEST as a valid timezone abbrevation? It's not listed
> in the "Default" abbreviation list. (Perhaps it should be, since there
> don't seem to be any places that don't consider it GMT+1 summer time.)
>
> regards, tom lane
>
select * from pg_timezone_names where abbrev = 'WEST' ;
name | abbrev | utc_offset | is_dst
------------------------+--------+------------+--------
Portugal | WEST | 01:00:00 | t
posix/Portugal | WEST | 01:00:00 | t
posix/WET | WEST | 01:00:00 | t
posix/Europe/Lisbon | WEST | 01:00:00 | t
posix/Atlantic/Canary | WEST | 01:00:00 | t
posix/Atlantic/Faeroe | WEST | 01:00:00 | t
posix/Atlantic/Madeira | WEST | 01:00:00 | t
posix/Atlantic/Faroe | WEST | 01:00:00 | t
WET | WEST | 01:00:00 | t
Europe/Lisbon | WEST | 01:00:00 | t
Atlantic/Canary | WEST | 01:00:00 | t
Atlantic/Faeroe | WEST | 01:00:00 | t
Atlantic/Madeira | WEST | 01:00:00 | t
Atlantic/Faroe | WEST | 01:00:00 | t
(14 rows)

It's interesting that there are (in my install of 9.1):

1174 distinct timezone names (all records are unique) in pg_timezone_names.
181 distinct abbreviations in pg_timezone_names

189 distinct timezone abbreviations (all unique abbreviations) in
pg_timezone_abbrevs.

But 61 abbreviations that appear in pg_timezone_names do not have a
corresponding entry in pg_timezone_abbrevs and 69 abbreviations in
pg_timezone_abbrevs that don't appear in pg_timezone_names.

There are 56 records and 3 different offsets in pg_timezone_names for
the abbreviation 'CST'.

I try to use timezone names instead of abbreviations wherever possible.

Cheers,
Steve