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

From: "Andrey M(dot) Borodin" <x4mmm(at)yandex-team(dot)ru>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Hannu Krosing <hannuk(at)google(dot)com>, Peter Eisentraut <peter(at)eisentraut(dot)org>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: What is a typical precision of gettimeofday()?
Date: 2024-11-02 08:37:26
Message-ID: 122E6623-E3B3-4945-9DF2-ADF86F7C63A7@yandex-team.ru
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> On 2 Jul 2024, at 20:55, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> Here's a cleaned-up code patch addressing the cfbot complaints
> and making the output logic a bit neater.
>
> I think this is committable code-wise, but the documentation needs
> work, if not indeed a complete rewrite. The examples are now
> horribly out of date, and it seems that the "Clock Hardware and Timing
> Accuracy" section is quite obsolete as well, since it suggests that
> the best available accuracy is ~100ns.
>
> TBH I'm inclined to rip most of the OS-specific and hardware-specific
> information out of there, as it's not something we're likely to
> maintain well even if we got it right for current reality.

Hi Tom!

This thread has associated CF entry which is marked as RwF [0]. But the change proved to be useful [1] in understanding what we can expect from time source.
It was requested many times before [2,3]. Reading through this thread it seems to me that my questions about application of the pg_test_timing somehow switched focus from this patch. However, I'd appreciate if it was applied. Nanoseconds seem important to me.
Let me know if I can help in any way. Thanks!

Best regards, Andrey Borodin.

[0] https://commitfest.postgresql.org/48/5066/
[1] https://www.postgresql.org/message-id/CAD21AoC4iAr7M_OgtHA0HZMezot68_0vwUCQjjXKk2iW89w0Jg@mail.gmail.com
[2] https://www.postgresql.org/message-id/CAMT0RQQJWNoki_vmckYb5J1j-BENBE0YtD6jJmVg--Hyvt7Wjg%40mail.gmail.com
[3] https://www.postgresql.org/message-id/flat/198ef658-a5b7-9862-2017-faf85d59e3a8%40gmail.com#37d8292e93ec34407a41e7cbf56e5481

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