This enum determines the partition key column for the bigquery tables.
Partitioning can improve query performance and reduce query cost by
filtering partitions. Refer to
https://cloud.google.com/bigquery/docs/partitioned-tables for details.
The time when the request is received. If specified as partition key,
the result table(s) is partitoned by the RequestTime column, an
additional timestamp column representing when the request was received.
Unspecified
Unspecified partition key. Tables won't be partitioned using this
option.