On Wed, Dec 7, 2011 at 08:21, Daoming Qiu <qdaoming@gmail.com> wrote:
"Beijing Time" is the standard time used for China region, so it is very strange that tzdatabase doesn't have timezone called Asia/Beijing.
The database does not follow, in general, country lines but rather regions that use the same timezone during the same period of time. And because cities change their names less often than countries do, the database usually uses city names (rather than country names) to identify such timezone regions, and in general (in my understanding) chooses the largest city within a timezone region to represent that region. This favours Shanghai over Beijing. You will note that there is also no America/Washington_DC, for example, or Australia/Canberra, or America/Brasilia. See also the "Theory" file in the tzcode distribution; this mentions some of the things taken into account when choosing names of time zones. (And it even has Shanghai/Beijing as an example: "Use the most populous among locations in a country's time zone, e.g. prefer `Shanghai' to `Beijing'.")
Strongly suggest to add "Asia/Beijing" zone into the database, and its information is very similar with "Asia/Shanghai".
If it is only "similar", can you please provide information on when Beijing used different time from Shanghai after January 1970? Then the tz database can be corrected and completed. Final disclaimer: I'm not a tz database maintainer and do not represent anyone maintaining it or setting the rules. The above is my understanding and interpretation. Cheers, Philip -- Philip Newton <philip.newton@gmail.com>