Hello Sam!  i am dealing with same issue as you, i see you made a question a year ago and i wonder, did you find a way to upload a Definition file from API rest ?  as you i have been tried and tired to build a process group with the file.json but documentation is not clear and does not offer an example to build the request.  i upload a file.json manually and checked the nifi-request.log and the only i see is this pettiotion " http://localhost:8081/process-groups/{id}/process-groups/upload" as "ok" did you find a way to build the body to send this request ?  thanks a lot, have a nice day.   ... View more

@samrathal  Apache NiFi has hardcoded return size to 100: https://github.com/apache/nifi/blob/main/nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/main/java/org/apache/nifi/web/dao/impl/StandardConnectionDAO.java#L361 I am sure this was originally done for performance and NiFi JVM heap usage reasons. The first 100 returned should be the oldest 100 in queue (keeping in mind that a connection will also show count of FlowFiles pending processing by downstream processor and count of those currently allocated to a downstream component process.  The listing only returns those pending FlowFiles and not those already owned by downstream component).What is the use case for needing to list more?  Ideally what is found in a queue should be changing rapidly, so expectation is that each listing request would be different. Listing a queue does not stop NiFi processing.  The intent is not for NiFi to ever hold FlowFiles in any connection.   So using API to  poll connection for FlowFile listings seems odd to me.  What is returned by that listing could be inaccurate milliseconds later. Also be careful with your API requests.  When a listing is performed through the browser three different request are made. 1. First listing-request is made and replicated to all nodes to get result sets.   2. Return from step 1 request gives the ID for the generated listing request being held in heap memory.  That ID is used to fetch the results in that specific listing ID 3. A DELETE request is made to remove the listing with that ID from NiFi.   *** When using API, If steps 1 and 2 are all that are being executed, the various listing request(s) will stay in heap memory. If you found any of the suggestions/solutions provided helped you with your issue, please take a moment to login and click "Accept as Solution" on one or more of them that helped. Thank you, Matt ... View more

@samrathal  Is your Windows server hosting a SFTP server that you can connect to?  If not, I'd expect GetSFTP/FetchSFTP to fail to connect.   If you can't reach your Windows file from command line on the server where NiFi resides, you are not going to be able to reach via a NiFi dataflow. 1. Setting up a windows share that you mount to your linux box would allow you to use ListFile and FetchFile processors. 2. Setting up an SFTP server on your Windows server would allow you to use ListSFTP and FetchSFTP processors. 3. Setting up SMB on your Windows server would allow you to use the ListSMB and FetchSMB processors. If you found that the provided solution(s) assisted you with your query, please take a moment to login and click Accept as Solution below each response that helped. Thank you, Matt ... View more