Description
SQL currently only supports reading from BigQuery in DEFAULT (EXPORT) mode. We also need to support DIRECT_READ mode. The method should be configurable by TBLPROPERTIES through the SQL CLI. This will enable us to take advantage of the DIRECT_READ features for filter and project push down.
References:
https://beam.apache.org/documentation/io/built-in/google-bigquery/#storage-api
https://beam.apache.org/blog/2019/06/04/adding-data-sources-to-sql.html