BUG #5658: 'at time zone {timezone description}' can't recognize many time zone abbreviations.

The following bug has been logged online:

Bug reference:      5658
Logged by:          Sangmin Ryu
Email address:      neocoin@gmail.com
PostgreSQL version: 8.3, 8.4.4
Operating system:   Ubuntu 8.04 , Ubuntu 10.04
Description:        'at time zone {timezone description}' can't recognize
many time zone abbreviations.
Details:

'at time zone {timezone description}' don't recognize many time zone
abbreviations.

Recently, my user request 'WIT' time zone.

---------------------------------------------------
postgres=# select current_timestamp at time zone 'PDT';
          timezone
----------------------------
 2010-09-15 11:32:28.449011
(1 row
postgres=# select current_timestamp at time zone 'WIT';
ERROR:  time zone "WIT" not recognized

postgres=# select * from pg_timezone_names where abbrev = 'WIT';
         name         | abbrev | utc_offset | is_dst
----------------------+--------+------------+--------
 posix/Asia/Pontianak | WIT    | 07:00:00   | f
 posix/Asia/Jakarta   | WIT    | 07:00:00   | f
 Asia/Pontianak       | WIT    | 07:00:00   | f
 Asia/Jakarta         | WIT    | 07:00:00   | f
(4 rows)

----------------------------------------------------

I checked changes version 7.x to 8.x. I found many timezone feature was
added at postgres version 8.x.

Maybe, 8.x version 'at time zone' keyword can recognize 7.x supported
abbreviations.


For example.

select current_timestamp at time zone 'zzz';