Can't change analyzer for _all field

[jaisharma]

ES=2.4.0
My configuration in elasticsearch.yml has default analyzer : keyword

index.analysis.analyzer.default.type: keyword

Now i've a field which stores notes and thus i want to analyze only this particular field. Thus i'm doing:

PUT /index10?pretty
{
  "mappings": {
    "my_type": {
      "properties": {
        "Notes_field": {
          "type": "string",
          "analyzer": "standard"
        }
      }
    }
  }
}

Now when i try to index my document, i get the error:

Document contains at least one immense term in field=\"_all\"

So i went back and corrected my mapping to make _all analyzed explicitly (as it might be using the default keyword analyzer):

PUT /index10?pretty
{
  "mappings": {
    "my_type": {
      "properties": {
        "Notes_field": {
          "type": "string",
          "analyzer": "standard"
        }
      }
    }
  },
  "_all": {
    "analyzer": "standard"
  }
}

But upon indexing, i get the same error as mentioned above. What am i doing wrong?

Please note that i don't want to disable the _all field. Also i don't want to exclude the Notes_fields from _all.

[jaisharma]

The issue was with the way i was putting mappings. _all has to be at the same level as properties while i kept it at the level of mappings.

This seems like a validation issue to me, _all settings should have a json structure validation to ensure people don't have to do this by trial and error.