Elasticsearch partial update script: Clear array and replace with new values

You can use the update by query API in order to do batch updates. This works since ES 2.3 onwards, otherwise you need to install a plugin.

POST index/_update_by_query
{
  "script": {
    "inline": "ctx._source.myProp += newProp",
    "params": {
      "newProp": "sit"
    }
  },
  "query": {
    "match_all": {}
  }
}

You can of course use whatever query you want in order to select the documents on which MyProp needs to be updated. For instance, you could have a query to select documents having some specific MyProp values to be replaced.

The above will only add a new value to the existing array. If you need to completely replace the MyProp array, then you can also change the script to this:

POST index/_update_by_query
{
  "script": {
    "inline": "ctx._source.myProp = newProps",
    "params": {
      "newProps": ["dolor", "sit"]
    }
  },
  "query": {
    "match_all": {}
  }
}

Note that you also need to enable dynamic scripting in order for this to work.

UPDATE

If you simply want to update a single document you can use the partial document update API, like this:

POST test/type1/1/_update
{
    "doc" : {
        "MyProp" : ["dolor", "sit"]
    }
}

This will effectively replace the MyProp array in the specified document.

If you want to go the bulk route, you don't need scripting to achieve what you want:

POST index/type/_bulk
{ "update" : {"_id" : "1"} }
{ "doc" : {"MyProp" : ["dolor", "sit"] } }
{ "update" : {"_id" : "2"} }
{ "doc" : {"MyProp" : ["dolor", "sit"] } }