On Fri, Apr 15, 2022 at 10:15 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > As well as the age of OldestXmin at the start of VACUUM.
>
> Is it worth capturing and logging both of those numbers? Why is
> the age at the end more interesting than the age at the start?
As Andres said, that's often more interesting because most of the time
OldestXmin is not held back by much (not enough to matter).
Users will often look at the output of successive related VACUUM
operations. Often the way things change over time is much more
interesting than the details at any particular point in time.
Especially in the kinds of extreme cases I'm thinking about.
--
Peter Geoghegan