You can enable a Bulk API task for monitoring. With monitoring enabled, the Data Integration service requests the status of each batch from the Salesforce and logs them in the session log.
By default, the Data Integration service does not monitor Bulk API jobs. Without monitoring, the activity log and session log contains information about batch creation, but does not contain details about batch processing or accurate job statistics.
Enable Serial Mode
The Salesforce service can perform a parallel or serial load for a Bulk API task. By default, it performs a parallel load.
In a parallel load, the Salesforce service writes batches to target at the same time. In a serial load, the Salesforce service writes batches to targets in the order it receives them.
Use a parallel load to increase performance when you are not concerned about the target load order. Use a serial load when you want to preserve the target load order.