Re: Clock-skew management in logical replication

On Mon, Sep 23, 2024 at 4:00 PM Nisha Moond <nisha(dot)moond412(at)gmail(dot)com> wrote:
>
> On Fri, Sep 20, 2024 at 7:51 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >
> > Nisha Moond <nisha(dot)moond412(at)gmail(dot)com> writes:
> > > While considering the implementation of timestamp-based conflict
> > > resolution (last_update_wins) in logical replication (see [1]), there
> > > was a feedback at [2] and the discussion on whether or not to manage
> > > clock-skew at database level.
> >
> > FWIW, I cannot see why we would do anything beyond suggesting that
> > people run NTP. That's standard anyway on the vast majority of
> > machines these days. Why would we add complexity that we have
> > to maintain (and document) in order to cater to somebody not doing
> > that?
> >
> > regards, tom lane
>
> Thank you for your response.
>
> I agree with suggesting users to run NTP and we can recommend it in
> the docs rather than introducing additional complexities.
>
> In my research on setting up NTP servers on Linux, I found that
> Chrony[1] is a lightweight and efficient solution for time
> synchronization across nodes. Another reliable option is the classic
> NTP daemon (ntpd)[2], which is also easy to configure and maintain.
> Both Chrony and ntpd can be used to configure a local machine as an
> NTP server for localized time synchronization, or as clients syncing
> from public NTP servers such as 'ntp.ubuntu.com' (default ntp server
> pool for Ubuntu systems) or 'time.google.com'(Google Public NTP).
> For example, on Ubuntu, Chrony is straightforward to install and
> configure[3]. Comprehensive NTP(ntpd) configuration guides are
> available for various Linux distributions, such as Ubuntu[4] and
> RedHat-Linux[5].
>
> Further, I’m exploring options for implementing NTP on Windows systems.
>

Windows platforms provide built-in time synchronization services. As a
client, they allow users to sync system time using internet or public
NTP servers. This can be easily configured by selecting a public NTP
server directly in the Date and Time settings. More details can be
found at [1].

Additionally, Windows servers can be configured as NTP servers for
localized time synchronization within a network, allowing other nodes
to sync with them. Further instructions on configuring an NTP server
on Windows can be found at [2].

[1] https://learn.microsoft.com/en-us/windows-server/networking/windows-time-service/how-the-windows-time-service-works
[2] https://learn.microsoft.com/en-us/troubleshoot/windows-server/active-directory/configure-authoritative-time-server

Thanks,
Nisha