Re: Should we remove vacuum_defer_cleanup_age?

> On 24 Mar 2023, at 21:27, Andres Freund <andres(at)anarazel(dot)de> wrote:
> On 2023-03-23 10:18:35 +0100, Daniel Gustafsson wrote:
>>> On 22 Mar 2023, at 18:00, Andres Freund <andres(at)anarazel(dot)de> wrote:
>>
>>> It wasn't actually that much work to write a patch to remove
>>> vacuum_defer_cleanup_age, see the attached.
>>
>> - and <xref linkend="guc-vacuum-defer-cleanup-age"/> provide protection against
>> + provides protection against
>> relevant rows being removed by vacuum, but the former provides no
>> protection during any time period when the standby is not connected,
>> and the latter often needs to be set to a high value to provide adequate
>>
>> Isn't "the latter" in the kept part of the sentence referring to the guc we're
>> removing here?
>
> You're right. That paragraph generally seems a bit off. In HEAD:
>
> ...
>
> Replication slots alone don't prevent row removal, that requires
> hot_standby_feedback to be used as well.
>
> A minimal rephrasing would be:
> <para>
> Similarly, <xref linkend="guc-hot-standby-feedback"/> on its own, without
> also using a replication slot, provides protection against relevant rows
> being removed by vacuum, but provides no protection during any time period
> when the standby is not connected. Replication slots overcome these
> disadvantages.
> </para>

+1, that's definitely an improvement.

--
Daniel Gustafsson