Re: postgresql timezone and OS localtime correspondence

Pavel Suderevsky <psuderevsky(at)gmail(dot)com> writes:
> My question is related to correspondence of postgresql "timezone" parameter
> with OS timezone settings in debian and red hat family systems.

> In debian by default postgresql "timezone" parameter value is "localtime"
> and it succesfully gets current OS timezone. (most probably it is not
> dynamically updated and with changing OS timezone postgresql to be
> restarted likewise, but still)

> In centos 7.2 postgresql doesn't accept "localtime" value and timezone must
> be specified directly.

The reason that happens is that Debian creates a symlink named "localtime"
within the timezone data file tree (probably via zic's -l option, though
maybe they do it by hand). Red Hat doesn't do that; they follow a
different historical convention in which /etc/localtime defines the system
default zone. Arguably, "zic -l" is a violation of filesystem layout
conventions, since it puts what ought to be system-specific configuration
data into /usr/share.

> So the common question is: is there a way to configure postgresql server to
> get OS localtime value rather than setting it manually in red hat family
> systems?

You could make your own symlink, though I'm unsure whether it'd survive
tzdata package updates.

regards, tom lane