Github user bbende commented on the issue:
https://github.com/apache/nifi/pull/2478
One other question, what do you envision people most likely do with the
output of this processor?
The reason I'm asking is because I'm debating if it makes sense to write
multiple JSON documents to a single flow file without wrapping them in an
array. GetHBase and FetchHBase didn't have this problem because they wrote a
row per flow file (which probably wasn't a good idea for GetHBase).
As an example scenario, say we have a bunch of rows coming out of this
processor using the col-qual-val format like:
```
{"id":"", "message":"The time is Mon Mar 05 10:20:07 EST 2018"}
{"id":"", "message":"The time is Mon Mar 05 10:21:03 EST 2018"}
{"id":"", "message":"The time is Mon Mar 05 10:22:44 EST 2018"}
{"id":"", "message":"The time is Mon Mar 05 10:22:44 EST 2018"}
{"id":"", "message":"The time is Mon Mar 05 10:22:44 EST 2018"}
{"id":"", "message":"The time is Mon Mar 05 10:22:44 EST 2018"}
{"id":"", "message":"The time is Mon Mar 05 10:22:44 EST 2018"}
{"id":"", "message":"The time is Mon Mar 05 10:22:44 EST 2018"}
{"id":"", "message":"The time is Mon Mar 05 10:22:44 EST 2018"}
```
If we then created a schema for this:
```
{
"name": "scan",
"namespace": "nifi",
"type": "record",
"fields": [
{ "name": "id", "type": "string" },
{ "name": "message", "type": "string" }
]
}
```
Then tried to use ConvertRecord with a JsonTreeReader and
CsvRecordSetWriter, to convert from JSON to CSV, we get:
```
id,message
"",The time is Mon Mar 05 10:20:07 EST 2018
```
It only ends up converting the first JSON document because the
JsonTreeReader doesn't know how to read multiple records unless its a JSON
array.
There may be cases where the current output makes sense so I'm not saying
to change it yet, but just trying to think of what the most common scenario
will be.
---
