Re: Improvements and additions to COPY progress reporting

On Wed, Mar 10, 2021 at 09:35:10AM +0100, Matthias van de Meent wrote:
> There are examples in which pg_stat_progress_* -views report
> inaccurate data. I think it is fairly reasonable to at least validate
> some part of the progress reporting, as it is one of the few methods
> for administrators to look at the state of currently running
> administrative tasks, and as such, this user-visible api should be
> validated.

Looking closer at 0002, the size numbers are actually incorrect on
Windows for the second query. The CRLFs at the end of each line of
emp.data add three bytes to the report of COPY FROM, so this finishes
with 82 bytes for bytes_total and bytes_processed instead of 79.
Let's make this useful but simpler here, so I propose to check that
the counters are higher than zero instead of an exact number. Let's
also add the relation name relid::regclass while on it.

The tests introduced are rather limited, but you are right that
something is better than nothing here, and I have slightly updated
what the tests sent previously as per the attached. What do you
think?
--
Michael