What causes INFER_SCHEMA_FAILURE?

One or more staged files are empty or contain only headers with no data rows. The file format specified does not match the actual file structure (e.g., Parquet file with a CSV format object). The stage path pattern matches no files — the files were not uploaded or were placed in a different path. The files are compressed with a codec that the file format object does not specify

How do I fix INFER_SCHEMA_FAILURE?

Step 1: Run LIST @your_stage_name PATTERN='.*your_pattern.*' to confirm files are present at the expected path.. Step 2: Verify the FILE FORMAT object type matches the actual file type (TYPE = PARQUET, JSON, CSV, etc.).. Step 3: Check that at least one file has data rows, not just a header.. Step 4: If using a LIMIT clause, remove it temporarily to see if schema detection succeeds with the full dataset.. Step 5: Re-upload the files and retry INFER_SCHEMA.

Medium severitydata_quality

Power BI Refresh Error:
INFER_SCHEMA_FAILURE

What does this error mean?

The Snowflake INFER_SCHEMA function could not determine column definitions from staged files because the files are empty, corrupt, in an unsupported format, or inaccessible on the stage.

Common causes

1One or more staged files are empty or contain only headers with no data rows
2The file format specified does not match the actual file structure (e.g., Parquet file with a CSV format object)
3The stage path pattern matches no files — the files were not uploaded or were placed in a different path
4The files are compressed with a codec that the file format object does not specify

How to fix it

1Step 1: Run LIST @your_stage_name PATTERN='.*your_pattern.*' to confirm files are present at the expected path.
2Step 2: Verify the FILE FORMAT object type matches the actual file type (TYPE = PARQUET, JSON, CSV, etc.).
3Step 3: Check that at least one file has data rows, not just a header.
4Step 4: If using a LIMIT clause, remove it temporarily to see if schema detection succeeds with the full dataset.
5Step 5: Re-upload the files and retry INFER_SCHEMA.

Frequently asked questions

Can INFER_SCHEMA handle mixed-type columns across files?

INFER_SCHEMA samples files and votes on the most likely type per column. Conflicting types across files can cause the function to fall back to VARCHAR. Use the IGNORE_CASE and MAX_RECORDS_PER_FILE options to improve accuracy.

Is there a way to preview what schema INFER_SCHEMA would produce before using it?

Yes — SELECT * FROM TABLE(INFER_SCHEMA(LOCATION=>'@your_stage', FILE_FORMAT=>'your_format')) returns the detected column names and types without creating any table.