Hi @rturn , Its an interesting case indeed. I'm not sure if this is intended by design or if its an actual bug. The fact that this happens only after the flowfiles exit the process group lead me to believe that whatever you are doing there it's indirectly causing this error.   Explanation: - Typically when you get such an error , it means that you are trying pass number of  value arguments to a query that doesnt have a matching number of column placeholders. You query doesnt list columns placeholders  (?)  hence the value 0 . The question is where is the 1 argument is coming from?   - If you read the PutSQL processor description it allows for a value argument placeholder using the question mark character (?) provided argument value\type tuple in the form of sql.args.N.type & sql.args.N.value as flowfile attributes, where N stands for the position of each argument placeholder in the sql command. - Given your data flow, it seems like you are doing some insert sql commands in the upstream process group while utilizing argument value placeholders. - When doing the Merge  (regardless how you set the Attribute Strategy) the merged output seem to keep those sql argument type & value attributes that are common (name & value)  across the merged flowfiles. - The PutSQL behavior (this is where its a potential bug) seem to always pass any provided sql argument regardless if the actual query has placeholders or not. When the JDBC tries to execute the query it sees you are providing arguments but there is no placeholders and therefore it throws this exception.   Mitigation: 1- One way to mitigate this issue is by adding an UpdateAttribute before the final PutSQL to delete all sql placeholder arguments with the following Regix in the "Delete Attribute Expression" property:   sql\.args\.[0-9]+\.(type|value)     2- Another option to avoid passing attributes that might indirectly cause unintended consequences to  downstream processors through using Process Group Concurrency and merge, as an alternative you can consider something like Wait-Notify pattern, however this will require a redesign of the dataflow. @MattWho  @stevenmatison , Do you think this qualifies to be reported as a bug? Steps to Reproduce: 1- Create starting processor like GetFile or GenerateFlowFile 2- Add UpdateAttribute processor to create the following attributes: 3- Add a PutSQL processor that executes any arbitrary crud statement that doesnt have any placeholders.   Resolution: Check the sql command for any placeholder and if there is none then dont pass arguments.   If that helps please accept the solution. Thanks         ... View more

Hi @drewski7 , I tried the code you have posted and it worked for me ! Here are the steps I followed: 1- Create Main Folder called TransformOpenskyStates-nar 2- Created  TransformOpenskyStates.py with the code you posted  under the main folder above. 3- Created the folder structure as follows:   3 - Under the META-INF I have created the MANIFEST.FM and add the following text: Manifest-Version: 1.0 Build-Timestamp: 2024-10-07T16:22:20Z Nar-Id: TransformOpenskyStates-nar Nar-Group: nifi.py.processors Nar-Version: 0.0.2 4- Under NAR-INF I have created an Empty folder of "bundled-dependencies" since you dont seem to have any external dependencies. 5-  I have downloaded and installed 7-zip then I went inside the main directory created at step 1 , selected all (2 folders and 1 py file) , right click , select 7-Zip menu item and then select Add to Archive 6- In the 7-Zip Add To Archive window,  type the name of your package and save as .zip. No need to change any configuration. If you create a zip file on the main folder level then it will add the main folder to the package and that might cause problem as nifi expects the py file to be on the root level and that could be your probelm. 7- rename the .zip to .nar and then I would try first to place it under the lib folder and if it works you can move it to others.   8 - Restart Nifi and in my case the log file had the following entries regarding this processor: 2024-10-14 20:10:00,495 INFO [main] org.apache.nifi.nar.NarClassLoaders Loaded NAR file: \nifi-2.0.0-M4-dev\.\work\nar\extensions\TransformOpenskyStates-nar.nar-unpacked as class loader org.apache.nifi.nar.NarClassLoader[.\work\nar\extensions\TransformOpenskyStates-nar.nar-unpacked] ... 2024-10-14 20:10:02,036 INFO [main] o.a.n.n.StandardExtensionDiscoveringManager Loaded extensions for nifi.py.processors:TransformOpenskyStates-nar:0.0.2 in 3 millis ... 2024-10-14 20:10:14,316 INFO [main] o.a.n.n.StandardExtensionDiscoveringManager Discovered Python Processor TransformOpenskyStates 9- Once UI is up and running , I m able to see and select the processor: When I ran it however I got an error but that is a different story 🙂   Error Message: 20:14:13 EDT ERROR 8d85ee2d-0192-1000-7594-fe7475f52c1d PythonProcessor[type=TransformOpenskyStates, id=8d85ee2d-0192-1000-7594-fe7475f52c1d] Failed to transform FlowFile[filename=e8370eae-8bdd-4867-91dc-1416fd5d4727]: py4j.Py4JException: An exception was raised by the Python Proxy. Return Message: Traceback (most recent call last): File "F:\nifi-2.0.0-M4-dev\python\framework\py4j\java_gateway.py", line 2466, in _call_proxy return_value = getattr(self.pool[obj_id], method)(*params) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "F:\nifi-2.0.0-M4-dev\python\api\nifiapi\flowfiletransform.py", line 33, in transformFlowFile return self.transform(self.process_context, flowfile) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "F:\nifi-2.0.0-M4-dev\.\work\nar\extensions\TransformOpenskyStates-nar.nar-unpacked\TransformOpenskyStates.py", line 49, in transform contents = json.loads(flow_file.getContentsAsBytes()) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "C:\Program Files\Python\311\Lib\json\__init__.py", line 346, in loads return _default_decoder.decode(s) ^^^^^^^^^^^^^^^^^^^^^^^^^^ File "C:\Program Files\Python\311\Lib\json\decoder.py", line 337, in decode obj, end = self.raw_decode(s, idx=_w(s, 0).end()) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "C:\Program Files\Python\311\Lib\json\decoder.py", line 355, in raw_decode raise JSONDecodeError("Expecting value", s, err.value) from None json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0) Im emailing you a copy of the zip file . Try to change it to nar and see if that works. Im suspecting that the way you package (zip) the folder structure is causing the issue.   Hope that helps.       ... View more