Re: Why is hot_standby_feedback off by default?

On 10/23/23 04:02, sirisha chamarthi wrote:
> On Sun, Oct 22, 2023 at 4:56 AM Vik Fearing  wrote:
> 
>> On 10/22/23 09:50, sirisha chamarthi wrote:
>>> Is there any specific reason hot_standby_feedback default is set to off?
>>
>>
>> Yes.  No one wants a rogue standby to ruin production.
>>
> 
> Agreed.


Okay...


> I believe that any reasonable use of a standby server for queries
> requires hot_standby_feedback to be turned on. Otherwise, we can
> potentially see query cancellations, increased replication lag because of
> conflicts (while replaying vacuum cleanup records) on standby (resulting in
> longer failover times if the server is configured for disaster recovery +
> read scaling). Recent logical decoding on standby as well requires
> hot_standby_feedback to be turned on to avoid slot invalidation [1]. If
> there is no requirement to query the standby, admins can always  set
> hot_standby to off. My goal here is to minimize the amount of configuration
> tuning required to use these features.
> 
> [1]:
> https://www.postgresql.org/docs/current/logicaldecoding-explanation.html


This does not sound like you agree.
-- 
Vik Fearing