Page History

...

First of all the PID mapping logic is updated to skip it for positive PIDs, making it idempotent. Rather than addressing collisions at runtime, this approach proactively eliminates stale state on failover. When mirroring stops, no mirrored producer remains active: the fetcher has been removed and the partition is about to become writable. All negative PIDs in the ProducerStateManager (PSM) are stale and can be safely expired. A MIRROR_PID_RESET control record (type 7) is written to each destination partition's log during the STOPPED STOPPING state transition, after the fetcher has been removed and truncation to last stable offset is complete, but before the partition opens for local writes. The dump tool is enhanced to deserialize and display MIRROR_PID_RESET records. Control batches are filtered out by the consumer fetcher, so the barrier is invisible to application consumers, just like transaction markers.

...