Nifi flow doesn't run and shows active threads message

Nifi flow has stopped working. Today, on starting the flow all the processors icon turns green, but there is no input or output as GenerateFlowFile shows active threads and terminated threads. This count keeps on increasing or decreasing if I terminate manually or start flow. I also tried to remove the GenerateFlowFile processor and create once again, but same result. On disabling all processors are disabled but not the GenerateFlowFile.

What is the reason behind this active thread and how to run the flow once again.

Solution

Opening the nifi-app.log file and clearing it resolved this issue for me.