pathwaycom/pathway · error · ValueError

{METADATA_COLUMN_NAME!r} is a reserved column name used by P

Error message

{METADATA_COLUMN_NAME!r} is a reserved column name used by Pathway's connector metadata. Declaring it in the schema would be silently shadowed by the connector. Rename your column to something else, or set 'with_metadata=True' to receive the auto-generated metadata in this column.

What it means

Error "{METADATA_COLUMN_NAME!r} is a reserved column name used by Pathway's connector metadata. Declaring it in the schema would be silently shadowed by the connector. Rename your column to something else, or set 'with_metadata=True' to receive the auto-generated metadata in this column." thrown in pathwaycom/pathway.

Source

Thrown at python/pathway/io/_utils.py:345

            ),
            schema_registry_settings=maybe_schema_registry_settings(
                schema_registry_settings
            ),
            message_queue_key_field=(
                MESSAGE_QUEUE_KEY_COLUMN_NAME if with_native_record_key else None
            ),
        )

    schema = assert_schema_not_none(schema, data_format_type)
    if METADATA_COLUMN_NAME in schema.column_names():
        if with_metadata:
            raise ValueError(
                f"The schema already declares a {METADATA_COLUMN_NAME!r} column, "
                f"which conflicts with 'with_metadata=True'. Either remove "
                f"{METADATA_COLUMN_NAME!r} from the schema or set "
                "'with_metadata=False'."
            )
        raise ValueError(
            f"{METADATA_COLUMN_NAME!r} is a reserved column name used by "
            "Pathway's connector metadata. Declaring it in the schema would "
            "be silently shadowed by the connector. Rename your column to "
            "something else, or set 'with_metadata=True' to receive the "
            "auto-generated metadata in this column."
        )
    if with_metadata:
        schema |= MetadataSchema

    schema, api_schema = read_schema(schema)
    if data_format_type == "dsv":
        if json_field_paths is not None:
            raise ValueError("Unexpected argument for csv format: json_field_paths")
        return schema, api.DataFormat(
            **api_schema,
            format_type=data_format_type,
            delimiter=",",
            schema_registry_settings=maybe_schema_registry_settings(

View on GitHub (pinned to fa2f74a464)

Solutions

1. Rename the '_metadata' column in your schema, or set with_metadata=True to let the connector fill it.

Example fix

t = t.select(*pw.this.without('_metadata'))

When it happens

Trigger: Thrown at python/pathway/io/_utils.py:345 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of pathwaycom/pathway@fa2f74a464 (2026-08-15). Data as JSON: /api/errors/fc079935c853bb0a. Report an issue: GitHub.