Re: Some thoughts about i/o priorities and throttling vacuum

Alvaro Herrera <alvherre@dcc.uchile.cl> writes:
> The trick to keep in mind is that the XID comparison functions use
> "modulo" operations, _but_ there are special "frozen" XIDs that are
> always "committed" -- that's why a VACUUM FREEZE would relieve the table
> forever from this problem.

> (At least this is how I understand it -- I could be totally wrong here)

No, that's exactly correct.
        regards, tom lane