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From: Bo Peng <[email protected]>
To: Luca Ferrari <[email protected]>
To: [email protected] <[email protected]>
Subject: Re: main vs primary
Date: Wed, 30 Jul 2025 10:03:41 +0000
Message-ID: <TYWP286MB2633D3F688B88656A74356EEF224A@TYWP286MB2633.JPNP286.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <CAKoxK+7ZbtVu6WEPtLze+HciX6S8aiRNhqQwD3R=CdwHdYQTRQ@mail.gmail.com>
References: <CAKoxK+7ZbtVu6WEPtLze+HciX6S8aiRNhqQwD3R=CdwHdYQTRQ@mail.gmail.com>

Hi,

The "primary node" refers to the PostgreSQL primary server in a streaming replication setup.
The "main node" indicates the main backend node, usually the first live backend (i.e., the one with the smallest node ID).
The term "main node" is typically used in native replication or snapshot isolation modes. In non-streaming replication modes, there is no primary/standby role, so Pgpool refers to the selected main backend as the "main node".

> LOG:  failover: 2 follow backends have been degenerated
> LOG:  failover: set new primary node: 1
> LOG:  failover: set new main node: 2
>
> in my scenario, the third host (so number 2) has been promoted. So
> what is the "primary" node 1 doing?

If node2 is promoted to the primary, the primary node should be shown as "node: 2".
Could you share more logs related to the failover, as well as your configuration file?

---
Bo Peng <[email protected]>
SRA OSS K.K.
TEL: 03-5979-2701 FAX: 03-5979-2702
Mobile: 080-7752-0749
URL: https://www.sraoss.co.jp/


________________________________________
差出人: Luca Ferrari <[email protected]>
送信: 2025 年 7 月 29 日 (火曜日) 19:32
宛先: [email protected] <[email protected]>
件名: main vs primary


Hi all,
sorry for the trivial question, but I cannot find this in
documentation, so please indicate me where I can find (in case I
missed).
What is the difference between main and primary nodes?

For example, in my logs I've:

LOG:  failover: 2 follow backends have been degenerated
LOG:  failover: set new primary node: 1
LOG:  failover: set new main node: 2

in my scenario, the third host (so number 2) has been promoted. So
what is the "primary" node 1 doing?

Thanks,
Luca

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