PREFIX.DIGEST
Order-insensitive checksum of a prefix's rows for migration verification.
PREFIX.DIGEST prefixComplexity
O(keys on the shard) to walk plus O(sum of row sizes) to digest, on every shard. Per-row digests XOR together, so the result is order-insensitive and safe across shard counts
Complexity and compatibility are read out of kevy's implementation, not copied from Redis's reference. Several genuinely differ.
Redis compatibility
kevy only
kevy has this; Redis does not. nearest is DEBUG DIGEST — comparable in kind (Redis also XORs per-key digests), but Redis's is whole-DB and lives behind DEBUG, while ours is per-prefix (the unit a migration actually cares about) and is a supported verb