@stephane_davy  Sorry I couldn't work on this further last week. Now my solution looks like this.   JSON from GenerateFlowFile [ { "myfield": "JustForHavingJson", "myfield1": "A" }, { "myfield": "JustForHavingJson", "myfield1": "B" }, { "myfield": "JustForHavingJson", "myfield1": "C" }, { "myfield": "JustForHavingJson", "myfield1": "D" }, { "myfield": "JustForHavingJson", "myfield1": "E" }, { "myfield": "JustForHavingJson", "myfield1": "X" }, { "myfield": "JustForHavingJson", "myfield1": "" } ]   Definitions of ControllerServices and AvroSchemaRegistry ControllerServices and AvroSchemaRegistry Flow Flow   Details of RecordProcessing-Processors Details RecordProcessing-Processors   Result FF-Content after MergeRecord: {"myfield":"JustForHavingJson","myfield1":"A","myfield2":"C"} {"myfield":"JustForHavingJson","myfield1":"B","myfield2":"C"} {"myfield":"JustForHavingJson","myfield1":"C","myfield2":""} {"myfield":"JustForHavingJson","myfield1":"E","myfield2":""} {"myfield":"JustForHavingJson","myfield1":"X","myfield2":""} {"myfield":"JustForHavingJson","myfield1":"","myfield2":""} {"myfield":"JustForHavingJson","myfield1":"D","myfield2":"G"} Personally I wouldn't do a MergeRecord at the end but go on with the three single connections of the UpdateRecord processors.   Do you think this could be a possible solution or have you found a better way to do this? ... View more

@ang_coder  The AvroSchemaRegistry is to set in the ControllerServices. If it should be available in your whole NiFi just go to the canvas and click anywhere right -> choose "Configure". It is the same place where you define your database connections. Configure -> ControllerServices If you already have JSON-format just ignore the first two steps of my example flow where data were retrieved and converted to JSON. Start with your JSON at UpdateAttribute which doesn't care about the kind of flowfile content. The ConvertRecord in my example uses an JSON-reader and JSON-writer where the writer points to the AvroSchemaRegistry with the schema.name set in UpdateAttribute. Therefore the JsonRecordSetWriter_IJ_TestMoreColumnsAtTarget (just to take a short name) has the specification "Schema Access Strategy" with option "Use Schema.Name Property". Have a look at the configuration details in my post before. Hope this helps. ... View more

@dzbeda  Try it with:  /*:Event/*:System/*:Channel ... View more

@ang_coder   Tried it myself and have to correct my idea a little bit. Have a look at my example. Here are my tables. The target table has two columns more than the source. Tables I defined following ControllerServices: ControllerServices And created this flow: Flow Here the information of the single processors: Processor information In my example it works. Sure there will be a more elegant solution but I don't know how. ... View more