Ron Johnson <ronljohnsonjr(at)gmail(dot)com> writes:
> Why is VACUUM FULL recommended for compressing a table, when CLUSTER does
> the same thing (similarly doubling disk space), and apparently runs just as
> fast?
CLUSTER makes the additional effort to sort the data per the ordering
of the specified index. I'm surprised that's not noticeable in your
test case.
regards, tom lane