Hi Matt. Thanks for taking the time to help troubleshoot. 1. Is this a standalone single NiFi instance or a NiFi multi-instance cluster setup? standalone single NiFi instance 2. How many partitions on your source NiFi Kafka topic? 4 3. How do you have your MergeContent processor configured? 4. When you say connection quickly fills up, what are the settings on the connection? 5. With your flow running and processing FlowFiles through the dataflow connections, what is the CPU load average.  You can find these details from within NiFi's UI from either the cluster UI under global menu in upper right corner or the system diagnostics Ui found in the controller UI also under the global menu. I wasn't able to find this menu to get the average. 6. Do you have a lot of other dataflows also running within this same NiFi? this is the only flow. Here's a screenshot of what the flow looks like while running. You can see the merged queue is full, which happens within a few seconds of the application starting. ... View more