Marc Munro <marc(at)bloodnok(dot)com> writes:
> According to the docs, timestamp with time zone takes less space than
> time with time zone with the same resolution. Is this a documentation
> bug?
Nope.
regression=# select typname,typlen from pg_type where typname like 'time%tz';
typname | typlen
-------------+--------
timestamptz | 8
timetz | 12
(2 rows)
> It makes no sense to me that by storing the date with the time you
> can save 4 bytes.
Actually, your mistake is in imagining that timestamptz represents the
timezone explicitly ... it doesn't. If it did, it'd be at least as
large as timetz.
regards, tom lane