apache/superset · error · DatabaseUploadFileTooLarge

Database upload file exceeds the maximum allowed size.

Error message

Database upload file exceeds the maximum allowed size.

What it means

DatabaseUploadFileTooLarge is raised by validate_file_size when the uploaded file exceeds UPLOAD_MAX_FILE_SIZE_BYTES. The check is shared by the upload command and the metadata endpoint so oversized files are rejected before being read into memory.

Source

Thrown at superset/commands/database/uploaders/base.py:262

        return size

    @classmethod
    def validate_file_size(cls, file: Any) -> None:
        """
        Reject a file whose size exceeds ``UPLOAD_MAX_FILE_SIZE_BYTES``.

        Shared by the upload command and the metadata endpoint so oversized
        files are rejected before their contents are read into memory,
        regardless of which path is used.

        :raises DatabaseUploadFileTooLarge: if the file is larger than the limit
        """
        max_file_size = current_app.config.get("UPLOAD_MAX_FILE_SIZE_BYTES")
        if max_file_size is None or file is None:
            return
        size = cls._file_size_bytes(file)
        if size is not None and size > max_file_size:
            raise DatabaseUploadFileTooLarge()

    @staticmethod
    def _resolve_default_schema(database: Database) -> Optional[str]:
        """Resolve the database's default schema so uploaded datasets carry an
        explicit schema instead of NULL, which would otherwise duplicate an
        existing dataset over the same table (see #36305)."""
        try:
            return database.get_default_schema(database.get_default_catalog())
        except Exception:  # pylint: disable=broad-except
            # Resolution opens an inspector connection; a failure here must
            # degrade to the no-schema behavior rather than fail the upload.
            logger.warning(
                "Unable to resolve default schema for upload; proceeding without one",
                exc_info=True,
            )
            return None

    def validate(self) -> None:

View on GitHub (pinned to f4587218dd)

Solutions

Split the file or upload a smaller extract
Raise UPLOAD_MAX_FILE_SIZE_BYTES in superset_config.py if the deployment can afford the memory
Stream/load the data directly into the database instead of the UI upload path

Example fix

# superset_config.py
 # before
 # (no override; default limit hit)

 # after
 UPLOAD_MAX_FILE_SIZE_BYTES = 500 * 1024 * 1024  # 500MB, if resources allow

Defensive patterns

Strategy: validation

Validate before calling

max_size = current_app.config.get("UPLOAD_MAX_FILE_SIZE_BYTES")
if max_size is not None:
    file.seek(0, 2)
    size = file.tell()
    file.seek(0)
    if size > max_size:
        raise ValueError(f"file {size}B exceeds limit {max_size}B")

Try / catch

try:
    UploadCommand(...).run()
except DatabaseUploadFileTooLarge:
    # prompt for a smaller/split file
    ...

Prevention

Check file size client-side before starting the upload
Chunk large datasets into the DB directly

When it happens

Trigger: Uploading a CSV/Excel larger than UPLOAD_MAX_FILE_SIZE_BYTES (default caps apply when configured); checking file metadata on an oversized file.

Common situations: Large exports uploaded without chunking; operators lowering the limit; environments with strict memory budgets.

Related errors

AI-assisted analysis of apache/superset@f4587218dd (2026-08-14). Data as JSON: /api/errors/aafea708a60df1e1. Report an issue: GitHub.