{ "schema_version": "1.0", "scenario_id": "dictionary_reencoded", "title": "Dictionary contents change without any value change", "category": "representation", "description": "Both versions store the same dictionary column with the same decoded values. The stored dictionaries differ: v0 has a different order and an entry that no row uses; v1 has exactly the used values. Schema, rows and values are unchanged, so both versions have the same logical fingerprint.", "notes": [ "Tools that compare dictionary indices, category lists or category codes observe a change here. The decoded values do not change.", "The unused dictionary entry survives a PyArrow round trip; other readers may rebuild the dictionary on read and drop it." ], "tags": [ "dictionary", "categorical", "encoding", "no-schema-change", "no-value-change" ], "row_identity": [ "id" ], "versions": [ { "id": "v0", "file": "v0.parquet", "row_count": 6, "fingerprint": "sha256:6dfdbf0a9de0eac2a01b3d7a88cb06abe18009dfa4d033259c14f39d7bf16d9b", "schema": [ { "name": "id", "type": "int64", "nullable": false }, { "name": "status", "type": "dictionary", "nullable": true } ], "writer": { "use_dictionary": true }, "dictionaries": [ { "path": "status", "values": [ "pending", "active", "inactive", "archived" ] } ] }, { "id": "v1", "file": "v1.parquet", "row_count": 6, "fingerprint": "sha256:6dfdbf0a9de0eac2a01b3d7a88cb06abe18009dfa4d033259c14f39d7bf16d9b", "schema": [ { "name": "id", "type": "int64", "nullable": false }, { "name": "status", "type": "dictionary", "nullable": true } ], "writer": { "use_dictionary": true }, "dictionaries": [ { "path": "status", "values": [ "active", "inactive", "pending" ] } ] } ], "transitions": [ { "from": "v0", "to": "v1", "mutations": [], "invariants": { "row_count_preserved": true, "row_identity_preserved": true, "rows_retained": true, "paths_retained": true, "common_values_preserved": true, "value_changes": [], "parquet_schema_preserved": true } } ] }