Re: Time delayed LR (WAS Re: logical replication restrictions)

On Wed, Jan 25, 2023 at 11:57 AM Kyotaro Horiguchi
<horikyota(dot)ntt(at)gmail(dot)com> wrote:
>
> At Tue, 24 Jan 2023 12:19:04 +0000, "Takamichi Osumi (Fujitsu)" <osumi(dot)takamichi(at)fujitsu(dot)com> wrote in
> > Attached the patch v20 that has incorporated all comments so far.
>
...
>
>
> + in which case no additional wait is necessary. If the system clocks
> + on publisher and subscriber are not synchronized, this may lead to
> + apply changes earlier than expected, but this is not a major issue
> + because this parameter is typically much larger than the time
> + deviations between servers. Note that if this parameter is set to a
>
> This doesn't seem to fit our documentation. It is not our business
> whether a certain amount deviation is critical or not. How about
> somethig like the following?
>

But we have a similar description for 'recovery_min_apply_delay' [1].
See "...If the system clocks on primary and standby are not
synchronized, this may lead to recovery applying records earlier than
expected; but that is not a major issue because useful settings of
this parameter are much larger than typical time deviations between
servers."

[1] - https://www.postgresql.org/docs/devel/runtime-config-replication.html

--
With Regards,
Amit Kapila.