Re: Determine if postgresql cluster running is primary or not - Mailing list pgsql-general

From Raul Kaubi
Subject Re: Determine if postgresql cluster running is primary or not
Date
Msg-id CAO_+3-DLkSM=1WN2=Hy8NRfCA=tbjH9uSPN-94CLwh4J06xNow@mail.gmail.com
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In response to Re: Determine if postgresql cluster running is primary or not  (Paul Förster <paul.foerster@gmail.com>)
List pgsql-general
Ok, Thanks! 

Raul

Kontakt Paul Förster (<paul.foerster@gmail.com>) kirjutas kuupäeval R, 20. november 2020 kell 12:54:
Hi Raul,

> On 20. Nov, 2020, at 11:45, Raul Kaubi <raulkaubi@gmail.com> wrote:
>
> Hmm, ok.
>
> But how is this possible..?
>
>  when b.sender>0 and c.receiver>0 then
>             'Primary+Replica'
>
> Raul

this happens for example if you have a primary a and replica b running as a normal cluster (we use Patroni for automatic failover) and then add another replica c to the existing replica b, effectively replicating: a => b => c In this case, b would be the replica of a, but also be the primary for c.

It's called cascading replication.

Cheers,
Paul

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