Jerome Wagner <jerome.wagner@laposte.net> writes:
> When compiled with "--with-system-tzdata", does postgres need a restart
> after the system is updated with the new tzdata ?
No, but existing sessions will carry on with whatever data they've read
from the tzdata files; we don't have a provision to reload a timezone
definition once read by a given process.
Whether you use --with-system-tzdata doesn't matter; the same would apply
if you were updating a Postgres-private copy of the tzdata files.
regards, tom lane