sourceUriPrefix

When hive partition detection is requested, a common for all source uris must be required. The prefix must end immediately before the partition key encoding begins. For example, consider files following this data layout. gs://bucket/path_to_table/dt=2019-06-01/country=USA/id=7/file.avro gs://bucket/path_to_table/dt=2019-05-31/country=CA/id=3/file.avro When hive partitioning is requested with either AUTO or STRINGS detection, the common prefix can be either of gs://bucket/path_to_table or gs://bucket/path_to_table/. Note that when mode is set to CUSTOM, you must encode the partition key schema within the source_uri_prefix by setting source_uri_prefix to gs://bucket/path_to_table/{key1:TYPE1}/{key2:TYPE2}/{key3:TYPE3}.