```json { "table_name": "columns_catalog", "primary_key": "id", "candidates": [ { "rank": 0, "partition_key": "id", "partition_key_label": "primary_identifier", "partition_key_reasoning": "RPUV = 1.00 (perfectly unique), uniqueness = 1.000, monotonicity = 1.000. This is the primary identifier for each column record in the catalog. While RPUV=1 typically indicates one file per row, for dimension tables the primary_identifier serves as the partition key by convention.", "clustering_key": null, "clustering_key_label": null, "clustering_key_reasoning": "Dimension tables do not require internal sorting. No clustering key needed.", "world_line": null, "session_column": null, "confidence": "HIGH", "notes": "This is a metadata dimension table cataloging column definitions. The id column is the unique identifier for each column record. The table references tables_catalog via tables_catalog_id (RPUV=79.28, indicating ~79 columns per table on average). No time axis exists. Dimension tables are typically small reference tables, but this one is large (1.5M rows) because it catalogs every column across all tables in the system." } ] } ```