Re: Timeline switching with partial WAL records can break replica recovery

Alena Vinter <dlaaren8@gmail.com>

From: Alyona Vinter <dlaaren8@gmail.com>
To: pgsql-hackers@lists.postgresql.org
Date: 2025-09-03T05:37:18Z
Lists: pgsql-hackers

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Hi hackers,

I've found an error in my previous patch and have attached a fixed version.

I'd also like to clarify the timeline switching bug scenario that this
patch fixes:
The issue occurs in this cluster configuration:
[ master ] → [ cascade replica ] → [ replica ]

When the master is lost and the cascade replica is promoted (as described
above), the downstream replica may enter an infinite loop during recovery
instead of properly following the new timeline.
--
Regards,
Alyona Vinter

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