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1. Two source clusters hash to the same 32-bit region. Unlikely
2. Both clusters have an active producer with the same local PID.

With a small number of source clusters (say 2-5), the probability of collision 1 is negligible. With many sources, the birthday paradox applies: you would need ~65,000 source clusters before reaching a 50% chance that any two share a hash. That is well beyond any realistic deployment.

Given the consequences, it is prudent to also have a resolution strategy. When the collision happens, we propose a resolution strategy to resolve it. We introduce the sourceClusterId optional field in ProducerSnapshot.json schema, bumping the version to 2. The sourceClusterId will be set only for mirrored PIDs, null for local producers.

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