Well I am not expert in migrating from a version to another so my answer might not be good enough for you :(. Besides that, I had no time to read the release notes for 1.21.0 and I am not quite sure if anything changed in terms of config files.   Assuming that you will keep the hostname and the port for each nifi node and you are using the embedded zookeeper, you should: 1. Stop the current NiFi instance. 2. Copy the authorizations.xml, authorizers.xml, bootstrap.conf, flow.json.gz, flow.xml.gz, logback.xml, login-identity-providers.xml, nifi.properties, stateless.properties, state-management.xml, users.xml and zookeeper.properties into the conf folder from within your new nifi instance. 3. Make sure that in nifi.properties, on your new instance, you are pointing to the same content repository, database repostiory (and all the other repositories) as in the previous instance --> assuming that you followed the best practices and had all those repositories moved on separate disks. Otherwise, make sure that you process all your data on your old instance and start fresh on your new instance. 4. Start the new NiFi Instance. If you are just interested in migrating just the flows from the canvas, you can add all your flows into a template and save them on your local machine. Afterwards, you can open your new nifi instance, upload your template and add it to your canvas. ... View more

In this case, you will need some extra steps. You could try something like: You have an ExecuteSQLRecord or ExecuteSQL, configured with the Database Connection Pooling Service and the Record Writer (if using ExecuteSQLRecord). Next, I would link the success queue to an ExtractText Processor. In this Processor I would add a new property called number_of_rows having the value " .* ". This will extract the value returned by count(*) and save it as an attribute in your FlowFile. Once you did this, you can link the success queue to an RouteOnAttribute Processor. Here, you will define a new property named bigger_as_zero and use the NiFi's EL to validate if the attribute is bigger than zero or not.   If bigger, you will send that message to the processor in which you have linked this queue. Otherwise, meaning that the value is zero, you can route the unmatched queue to another ExecuteSQL/ExecuteSQLRecord. You could also apply NiFi's EL to check if the value is exactly zero, if that is what you are looking for and route the file accordingly. NiFi's EL: https://nifi.apache.org/docs/nifi-docs/html/expression-language-guide.html Everything mentioned above has to be done, in addition to what @SAMSAL already said, with the fact that you need to modify you running schedule from 0 seconds to a greater value. 0 means that you will constantly execute this SQL Record. Here you will have to modify the value based on your project's requirements. ... View more

@DrManu, I do not think that you will find a processor in NiFi which will extract only the folder name out of your location 😞 You will either have to write your own processor or use a combination of several others, already part of NiFi. How I would honestly try the mentioned scenario: - An ExecuteStreamCommand Processor in which you have defined a custom made script which will read your folder structure and generate a JSON File, where each row is basically a complete path to a specific Folder. - Afterwards, you could use an SplitJson to generate a single FlowFile for each Folder and send it down your stream for further processing. ... View more