Update partial document

[Vincenzo D'Amore]

Hi Solr gurus :)

I have a delicious question (that I'm struggling with), really hope that
someone can help me.

There is a document with many fields but I have to modify only few of them.

I thought to use atomic update but it seems that I cannot replace an entire
list of dynamic fields.

Here I try to explain my problem, for example using the schemaless
configuration, I have a dynamic field:

<dynamicField name="attr_*" type="text_general" indexed="true"
stored="true" multiValued="true"/>

And then I have a document :

     {
        "id":"aaa",
        "value_i":10,
        "attr_1":["a"]
     }

I suppose to be able to remove attr_1 and add attr_3 with one atomic update.

Like this:

curl -X POST -H 'Content-Type: application/json' '
http://localhost:8983/solr/gettingstarted/update?versions=true&commit=true'
--data-binary '
 [
    {
      "id" : "aaa" ,
      "attr_" : [ "set" : null ],
      "attr_3" : [ "set" : "x" ]
    }
]'

But as result I only have a new attr_3 field (the field attr_1 is still
there)

     {
        "id":"aaa",
        "value_i":10,
        "attr_1":["a"],
        "attr_3":["x"]
     }

So it seem that, for this particular case, I have first to read the
document and then I can update it.

Do you think there are other options?
Can I use the StatelessScriptUpdateProcessorFactory ?
Should I write my own UpdateProcessor ?

Thanks in advance for your time.
Vincenzo

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Vincenzo D'Amore