Which Extraction Tool for BigQuery?

Matching tools to migration and integration needs depends on coding preference, transformation depth, and starting point. For an initial warehouse load, the common pattern is to export schema and data to vendor-neutral files such as Avro, ORC, or Parquet, upload those files to a Cloud Storage bucket in the same location as the BigQuery dataset, and then load through the transfer service, Dataflow, or Cloud Data Fusion. Use Avro, ORC, or Parquet to keep schema embedded with the data, while CSV requires the schema to be specified separately at load time or auto-detected.