Update control-flow-execute-data-flow-activity.md

Author: kromerm

articles/data-factory/control-flow-execute-data-flow-activity.md

@@ -8,7 +8,7 @@ ms.subservice: data-flows
 ms.custom: synapse
 ms.topic: conceptual
 ms.author: makromer
-ms.date: 09/09/2021
+ms.date: 03/22/2022
 ---
 
 # Data Flow activity in Azure Data Factory and Azure Synapse Analytics
@@ -101,6 +101,10 @@ A minimum compute type of General Purpose with an 8+8 (16 total v-cores) configu
 
 If you're using an Azure Synapse Analytics as a sink or source, you must choose a staging location for your PolyBase batch load. PolyBase allows for batch loading in bulk instead of loading the data row-by-row. PolyBase drastically reduces the load time into Azure Synapse Analytics.
 
+## Checkpoint key
+
+When using the change capture option for data flow sources, ADF will maintain and manage the checkpoint for you automatically. The default checkpoint key is a hash of the data flow name and the pipeline name. If you are using a dynamic pattern for your source tables or folders, you may wish to override this hash and set your own checkpoint key value here.
+
 ## Logging level
 
 If you do not require every pipeline execution of your data flow activities to fully log all verbose telemetry logs, you can optionally set your logging level to "Basic" or "None". When executing your data flows in "Verbose" mode (default), you are requesting the service to fully log activity at each individual partition level during your data transformation. This can be an expensive operation, so only enabling verbose when troubleshooting can improve your overall data flow and pipeline performance. "Basic" mode will only log transformation durations while "None" will only provide a summary of durations.