Parquet Metadata

The parquet_metadata function can be used to query the metadata contained within a Parquet file, which reveals various internal details of the Parquet file such as the statistics of the different columns. This can be useful for figuring out what kind of skipping is possible in Parquet files, or even to obtain a quick overview of what the different columns contain.

SELECT *
FROM parquet_metadata('test.parquet');

Below is a table of the columns returned by parquet_metadata.

Parquet Schema

The parquet_schema function can be used to query the internal schema contained within a Parquet file. Note that this is the schema as it is contained within the metadata of the Parquet file. If you want to figure out the column names and types contained within a Parquet file it is easier to use DESCRIBE.

-- fetch the column names and column types
DESCRIBE SELECT * FROM 'test.parquet';
-- fetch the internal schema of a Parquet file
SELECT *
FROM parquet_schema('test.parquet');

Below is a table of the columns returned by parquet_schema.

Parquet File Metadata

The parquet_file_metadata function can be used to query file-level metadata such as the format version and the encryption algorithm used.

SELECT *
FROM parquet_file_metadata('test.parquet');

Below is a table of the columns returned by parquet_file_metadata.

Parquet Key-Value Metadata

The parquet_kv_metadata function can be used to query custom metadata defined as key-value pairs.

SELECT *
FROM parquet_kv_metadata('test.parquet');

Below is a table of the columns returned by parquet_kv_metadata.