Unnest object (flatten JSON)

This processor unnests / flattens JSON objects or arrays. Example ——- For input in column jsoncol: {"firstname" : "a", "lastname" : "b", "details" : { "uid": 237, "comment" : " a comment"}

Output will be:

  • jsoncol.firstname = a

  • jsoncol.lastname = b

  • jsoncol.details.uid = 237

  • jsoncol.details.comment = a comment # Handling of arrays By default, arrays are kept untouched, ie:

  • If the column contains a JSON object which contains a JSON array, the JSON array will be preserved a single column

  • If the column contains a JSON array at top level, then the processor will do nothing

You can manually enable flattening of JSON arrays. Beware: very large arrays could lead to high memory and CPU consumption.