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(at)gmail(dot)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';