Re: timezone GUC

On ons, 2011-09-07 at 17:16 -0400, Tom Lane wrote:
> Magnus Hagander <magnus@hagander.net> writes:
> > On Tue, Sep 6, 2011 at 23:52, Robert Haas <robertmhaas@gmail.com> wrote:
> >> On Tue, Sep 6, 2011 at 5:16 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >>> Although there's always more than one way to skin a cat. Consider
> >>> this idea:
> >>> 
> >>> 1. The hard-wired default for timezone is always UTC (or something
> >>> else not dependent on environment).
> >>> 
> >>> 2. We put the identify_system_timezone work into initdb, and have it
> >>> inject a non-default entry into postgresql.conf in the usual way
> >>> if it can identify what the system zone is.
> >>> 
> >>> 3. Run-time dependency on TZ environment disappears altogether.
> >>> 
> >>> This basically means that instead of incurring that search on every
> >>> postmaster start, we do it once at initdb. If you change the
> >>> postmaster's timezone environment, well, you gotta go change
> >>> postgresql.conf.
> 
> >> Seems reasonable to me...
> 
> > +1.
> 
> I spent a bit of time on this idea last night.  The most painful part
> actually seems to be translating identify_system_timezone to run in a
> non-backend environment (no elog, etc).  The one thing I've run into
> that doesn't seem straightforward is to decide where to look for the
> timezone files.  If we have --with-system-tzdata then of course it's a
> constant, but should we honor initdb's -L switch otherwise?  And if so,
> how should we pass that into the pg_TZDIR code?
> 
>             regards, tom lane
> 

It looks like the --with-system-tzdata case is somewhat broken now in
initdb:

creating configuration files ... could not open directory "...../pg-install/share/timezone": No such file or directory
ok