Hi @bhagi  This can happen when the processor is terminated but the thread is not finished. When NiFi terminates a processor it does an interrupt, once that happen it should do a graceful shutdown, but it's not guaranteed. In any case, that shouldn't stop the processor from running again. Please see the following question: https://community.cloudera.com/t5/Support-Questions/0-active-threads-1-terminated-QueryDatabaseTable-processor/m-p/234682 And the NiFi User guide: https://nifi.apache.org/docs/nifi-docs/html/user-guide.html#terminating_tasks Was your question answered? Make sure to mark the answer as the accepted solution. If you find a reply useful, say thanks by clicking on the thumbs up button.   ... View more

Every flowfile is held in memory for as long as the flowfile is in the flow, until it reaches a DROP event[1]. This means, that if you're writing a large attribute (such as a json) this will eventually add up to a large heap usage. Keep in mind that the attributes also get stored in data provenance so there's also an impact there.   Biggest consequence to this a risk of NiFi going OOM, then failing to load the flowfile repository on startup. If the flowfile repo is too large it can also take longer for NiFi to start up, or also go OOM on startup while trying to load the repositories.   This is also touched on the Anti-patterns video[2] [1]https://nifi.apache.org/docs/nifi-docs/html/user-guide.html#provenance_events [2]https://www.youtube.com/watch?v=RjWstt7nRVY ... View more

Hi Joe, You could use ControlRate to set the max number of flowfiles per second/minute that needs to be routed.   In order to periodically clean the incoming queue you can set a Flowfile Expiration on the incoming connection. Connection config: ControlRate config:   With this, flowfiles on the connection will be cleared after they've been for more than 30 seconds on the queue.  ... View more