Google BigQuery Connectors > Part III: Data Integration with Google BigQuery Connector > Synchronization Tasks with Google BigQuery Connector > Read Modes
  

Read Modes

When you use Google BigQuery Connector, you can read data by using direct mode or staging mode. Before you choose a mode, see the Google documentation to understand the cost implications and trade-offs for each mode.
You can read data from a Google BigQuery source by using one of the following modes:
Direct Mode
Use direct mode when the volume of data that you want to read is small. In direct mode, Google BigQuery Connector directly reads data from a Google BigQuery source. You can configure the number of rows that you want Google BigQuery Connector to read in one request.
Staging Mode
Use staging mode when you want to read large volumes of data in a cost-efficient manner.
In staging mode, Google BigQuery Connector first exports the data from the Google BigQuery source into Google Cloud Storage. After the export is complete, Google BigQuery Connector downloads the data from Google Cloud Storage into a local stage file. You can configure the local stage file directory in the advanced source properties. Google BigQuery Connector then reads the data from the local stage file.
When you enable staging file compression, Google BigQuery Connector compresses the size of the staging file in Google Cloud Storage. Google BigQuery Connector then downloads the staging file and decompresses the staging file before it reads the file. To improve the performance and download data in parallel, you can configure the number of threads for downloading the staging file.