"David G. Johnston" <david.g.johnston@gmail.com> writes: > Indeed I presume it is. I wonder whether a carefully chosen timezone > specification on the server would cause this to break since the server can > be made to report the offset using either convention and so at least for > some timezone specifications the flipping of the sign would not be required…
AFAIK, "reporting the offset" is always done with the ISO convention. It's only when trying to interpret a time zone specification that we consider the POSIX convention (and that's mostly because the underlying tzdb code does so). This does lead to fun stuff like
postgres=# set timezone = 'GMT+2'; -- read as POSIX zone spec SET postgres=# select now(); now ------------------------------- 2022-01-19 13:03:36.000152-02 -- report as ISO (1 row)
postgres=# set timezone = '+2'; -- read as numeric ISO offset SET postgres=# select now(); now ------------------------------- 2022-01-19 17:03:41.722767+02 -- report as ISO (1 row)
IMO, all these cases are best-avoided legacy conventions. In practice you should set the timezone using the tzdb zone name for where you live, e.g. America/New_York.
regards, tom lane
Thanks Tom
We don't really deal with +2 without GMT in java so this isn't an issue. The code really only switches POSIX to ISO
