Re: logical replication restrictions

On Wed, Sep 22, 2021, at 1:18 AM, Amit Kapila wrote:
> On Tue, Sep 21, 2021 at 4:21 PM Marcos Pegoraro <marcos(at)f10(dot)com(dot)br> wrote:
>> No, I´m talking about that configuration you can have on standby servers
>> recovery_min_apply_delay = '8h'
>>
>
> oh okay, I think this can be useful in some cases where we want to avoid data loss similar to its use for physical standby. For example, if the user has by mistake truncated the table (or deleted some required data) on the publisher, we can always it from the subscriber if we have such a feature.
>
> Having said that, I am not sure if we can call it a restriction. It is more of a TODO kind of thing. It doesn't sound advisable to me to keep growing the current Restrictions page [1].
It is a new feature. pglogical supports it and it is useful for delayed
secondary server and if, for some business reason, you have to delay when data
is available. There might be other use cases but these are the ones I regularly
heard from customers.

BTW, I have a WIP patch for this feature. I didn't have enough time to post it
because it lacks documentation and tests. I'm planning to do it as soon as this
CF ends.

--
Euler Taveira
EDB https://www.enterprisedb.com/