Horton

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

Bernd Helmle <mailings@oopsware.de>

View thread
From: Bernd Helmle <mailings@oopsware.de>
To: Tom Lane <tgl@sss.pgh.pa.us>, Hannu Krosing <hannuk@google.com>
Cc: "Andrey M. Borodin" <x4mmm@yandex-team.ru>, Peter Eisentraut <peter@eisentraut.org>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2025-07-11T09:56:28Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Force LC_NUMERIC to C while running TAP tests.

  2. Minor tweaks for pg_test_timing.

  3. Change pg_test_timing to measure in nanoseconds not microseconds.

Am Dienstag, dem 08.07.2025 um 11:25 -0400 schrieb Tom Lane:
> Hannu Krosing <hannuk@google.com> writes:
> > On Mon, Jul 7, 2025 at 11:38 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > > 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%.
> 
> OK, pushed after a bit more fooling with the documentation.

FYI, since this commit TAP test pg_test_timing/001_basic on my machine
with de_DE.UTF8 locale keeps failing with:

stderr:
#   Failed test 'pg_test_timing: sanity check: matches'

[...]

# Observed timing durations up to 99,9900%:
#       ns   % of total  running %      count
#       20      60,2761    60,2761   25185754
#       21       2,3724    62,6485     991291
#       30      35,0016    97,6501   14625052
#       31       2,1129    99,7631     882874
#       40       0,2038    99,9669      85169
#       41       0,0166    99,9835       6933
#       50       0,0086    99,9921       3584
# ...
#   230806       0,0000   100,0000          1
# '
#     doesn't match '(?^sx:
# Testing\ timing\ overhead\ for\ 1\ second\..*
# Histogram\ of\ timing\ durations\:.*
# Observed\ timing\ durations\ up\ to\ 99\.9900\%\:
# )'
# Looks like you failed 1 test of 18.

(test program exited with status code 1)

Of course this is because of the localized comma in 99,9900%, as
executing with

LANG=C meson test -q --print-errorlogs pg_test_timing/001_basic

let this test succeed.

	Bernd