Re: Progress reporting for pg_verify_checksums

Bonjour Michaël,

> Getting to know the total size and the current size are the two
> important factors that matter when it comes to do progress reporting
> in my opinion. I have read the patch, and I am not really convinced
> by the need to show the progress report based on an interval of 250ms
> as we talk about an operation which could take dozens of minutes.

I do not think that it matters. I like to see things moving, and the
performance impact is null.

> So I have simplified the patch to only show a progress report every
> second. This also removes the include for the time-related APIs from
> portability/.

I do not think that it is a good idea, because Michael is thinking of
adding some throttling capability, which would be a very good thing, but
which will need something precise, so better use the precise stuff from
the start. Also, the per second stuff induces rounding effects at the
beginning.

> A second thing is that I don't think that the speed is much useful.

Hmmm. I like this information because I this is where I have expectations,
whereas I'm not sure whether 1234 seconds for 12.3 GB is good or bad, but
I know that 10 MB/s on my SSD is not very good.

> I would expect the speed to be steady, still there is a risk to show
> incorrect information if the speed of the operation is spiky or
> irregular leading to an incorrect estimation of the remaining time.

Hmmm. That is life, I'd say I'm used to it.

> In short, I would like to commit the first patch as attached, which is
> much more simple than what has been sent previously, still it provides
> the progress information which is useful.

I would prefer that you would keep the patch with the initial precision &
features for the reasons outlined above, but you are the committer and I'm
only a reviewer.

--
Fabien.