Re: Automating Failover Resync & Re-Attach in pgpool2

Hi,

Thank you for your question.

> While working with PostgreSQL failover scenarios, I noticed that the process of re-attaching a standby node
> after a failover can be somewhat manual and prone to delays, especially in production environments.

After a failover, the standby nodes can be automatically attached to the new primary by setting "follow_primary_command".

https://www.pgpool.net/docs/latest/en/html/runtime-config-failover.html#RUNTIME-CONFIG-FAILOVER-SETTINGS

You can also automatically reattach a failed standby node by setting "auto_failback = on".

https://www.pgpool.net/docs/latest/ja/html/runtime-config-failover.html#GUC-AUTO-FAILBACK

---
Bo Peng <pengbo(at)sraoss(dot)co(dot)jp>
SRA OSS K.K.
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________________________________________
差出人: VASUKI M <vasukim1992002(at)gmail(dot)com>
送信: 2025 年 10 月 10 日 (金曜日) 21:17
宛先: pgsql-bugs(at)lists(dot)postgresql(dot)org <pgsql-bugs(at)lists(dot)postgresql(dot)org>
Cc: bharatdb(at)cdac(dot)in <bharatdb(at)cdac(dot)in>; pgpool-general(at)lists(dot)postgresql(dot)org <pgpool-general(at)lists(dot)postgresql(dot)org>
件名: Automating Failover Resync & Re-Attach in pgpool2

Dear PostgreSQL and Pgpool Communities,
While working with PostgreSQL failover scenarios, I noticed that the process of re-attaching a standby node after a failover can be somewhat manual and prone to delays, especially in production environments.
I explored automating this process using a combination of pg_rewind and WAL replay, which allows a standby node to resynchronize and re-attach to the primary automatically after a failover. This could reduce downtime and simplify management of failover nodes in high-availability setups.
Automatically resynchronize after failover
Reduce downtime and ensure quicker recovery
Minimize manual operations and errors
Maintain consistent cluster state with less administrative overhead
I believe that integrating such an automated resync and re-attach feature into Pgpool-II could be very valuable for PostgreSQL users, potentially as an enhancement in a future release.
I wanted to share this idea with the community to get feedback, suggestions, or any pointers on existing work that may align with this. I am happy to contribute more details