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Encountering an empty snapshot file means that that particular Kafka broker will treat all idempotent producers who produced prior to the offset of the snapshot file as expired. In the situation where a follower broker has rebuilt the auxiliary state from an empty snapshot, the leader broker has just gone down, some producer identifiers have not produced since the offset of the empty snapshot, and the follower broker will become the leader, then those producer identifiers will be expired potentially resulting in duplicate records. Given that after the upgrade to from < 2.8 to 3.6 segments will start having an associated snapshot the above situation also needs to happen in the window during the upgrade. In summary, an empty snapshot is not risk free, but the combination of factors makes it unlikely to cause problems.

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