Re: sqlite3

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: emacs-devel@gnu.org
> Date: Tue, 28 Dec 2021 08:17:03 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Hmmm... but our w32 'stat' emulation only supports time_t times,
> > i.e. 1-second resolution.  Could that be the reason for the problem?
> 
> Yes, that would explain what we're seeing.  Is there any chance the w32
> stat emulation could be fixed to support sub-second resolutions like it
> does on other systems?

It could, but it's not a trivial job, and doing it just for this use
case could be overkill.

Besides, Emacs does work with 'stat' which doesn't provide sub-second
resolution, so this is not a w32 specific problem, at least in theory.

> If not, I think we'll have to change how the values are stored, and add
> a "header" section in the files themselves, so you'd have

I think this is a good idea anyway.  Because we could have fast
machines and disks that defeat even the best time resolution.

> ---
> Timestamp: <high res timestamp>

Do we really need time?  That could fail due to clock skew, if the
values are modified from different machines.  Wouldn't just a single
"generation number", that keeps only increasing, be enough?