Re: What is a typical precision of gettimeofday()?

On Mon, Jul 7, 2025 at 11:38 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>

> > Also added a flag to select number of direct values to show
>
> Hmm ... I agree with having a way to control the length of that output,
> but I don't think that specifying a count is the most useful way to
> do it. Particularly with a default of only 10, it seems way too
> likely to cut off important information.
>
> What do you think of instead specifying the limit as the maximum
> running-percentage to print, with a default of say 99.99%? That
> gives me results like

I agree that percentage covered is a much better metric indeed.
And I am equally ok with a default of either 99.9% or 99.99%.

I briefly thought of it but decided a simple count is simpler to
explain, especially for some potential corner cases of % .
But as pg_test_timing is not part of the server we really do not need
to worry about rare edge cases.

> Observed timing durations up to 99.9900%:
> ns % of total running % count
> 15 4.5452 4.5452 8313178
> 16 58.3785 62.9237 106773354
> 17 33.6840 96.6078 61607584
> 18 3.1151 99.7229 5697480
> 19 0.2638 99.9867 482570
> 20 0.0093 99.9960 17054
>
> In the attached I also made it print the largest observed
> duration, which seems like it might be useful information.

Yes, a useful piece of information indeed.

> As previously threatened, I also added a test case to
> improve the code coverage.

Thanks!