Google BigQuery Connectors > Part II: Data Integration with Google BigQuery V2 Connector > Mappings and mapping tasks with Google BigQuery V2 Connector > Write modes
  

Write modes

When you use Google BigQuery V2 Connector, you can write data by using bulk mode or streaming mode. Before you choose a mode, see the Google documentation to understand the cost implications and trade-offs for each mode.
You can write data to a Google BigQuery target by using one of the following modes:
Bulk mode
Use bulk mode when you want to write large volumes of data in a cost-efficient manner.
In bulk mode, Google BigQuery V2 Connector first writes the data to a staging file in Google Cloud Storage. When the staging file contains all the data, Google BigQuery V2 Connector loads the data from the staging file to the Google BigQuery target.
When you enable staging file compression, Google BigQuery V2 Connector compresses the size of the staging file before it writes data to Google Cloud Storage. Google BigQuery V2 Connector writes the compressed file to Google Cloud Storage and then submits a load job to the Google BigQuery target.
Note: Enabling compression reduces the time that Google BigQuery V2 Connector takes to write data to Google Cloud Storage. However, there will be a performance degradation when Google BigQuery V2 Connector writes data from Google Cloud Storage to the Google BigQuery target.
Google BigQuery V2 Connector deletes the staging file unless you configure the task or mapping to persist the staging file. You can choose to persist the staging file if you want to archive the data for future reference.
Streaming mode
Use streaming mode when you want the Google BigQuery target data to be immediately available for querying and real-time analysis. Evaluate Google's streaming quota policies and billing policies before you use streaming mode.
In streaming mode, Google BigQuery V2 Connector directly writes data to the Google BigQuery target. Google BigQuery V2 Connector appends the data into the Google BigQuery target.
You can configure the number of rows that you want Google BigQuery V2 Connector to stream in one request. If you want to stream a larger number of rows than the maximum permissible limit prescribed by Google, you can write the data to multiple smaller target tables instead of one large target table. You can create a template table based on which Google BigQuery must create multiple tables. You can define a unique suffix for each table. Google BigQuery creates each table based on the template table and adds the suffix to uniquely identify each table.
CDC mode
Use CDC mode only when you capture changed data from a CDC source. In CDC mode, you can configure Google BigQuery V2 Connector to capture changed data from any CDC source and write the changed data to a Google BigQuery target table.