Field [content] not present as part of path [content] when update_by_query

[sherry_cs (sherry)]

Hi, guys. I created an index with a pipeline which extracted field from the file attachments.
It works well except the partial update. I tried the request :

POST test_know/_update/G3LH2oIBXGHwpDNidXe9
{
  "doc": {
    "file_name": "new name"
  }
}

And the response:

{
  "error" : {
    "root_cause" : [
      {
        "type" : "illegal_argument_exception",
        "reason" : "field [content] not present as part of path [content]"
      }
    ],
    "type" : "illegal_argument_exception",
    "reason" : "field [content] not present as part of path [content]"
  },
  "status" : 400
}

The mapping looks like:

{
  "mappings": {
    "_doc": {
      "properties": {
        "attachment": {
          "properties": {
            "author": {
              "type": "text",
              "fields": {
                "keyword": {
                  "type": "keyword",
                  "ignore_above": 256
                }
              }
            },
            "content": {
              "type": "text",
              "fields": {
                "keyword": {
                  "type": "keyword",
                  "ignore_above": 256
                }
              }
            },
            "content_length": {
              "type": "long"
            },
            "content_type": {
              "type": "text",
              "fields": {
                "keyword": {
                  "type": "keyword",
                  "ignore_above": 256
                }
              }
            },
            "date": {
              "type": "date"
            },
            "language": {
              "type": "text",
              "fields": {
                "keyword": {
                  "type": "keyword",
                  "ignore_above": 256
                }
              }
            },
            "title": {
              "type": "text",
              "fields": {
                "keyword": {
                  "type": "keyword",
                  "ignore_above": 256
                }
              }
            }
          }
        },
        "author": {
          "type": "text",
          "fields": {
            "keyword": {
              "type": "keyword",
              "ignore_above": 256
            }
          }
        },     
        "file_name": {
          "type": "text",
          "fields": {
            "keyword": {
              "type": "keyword",
              "ignore_above": 256
            }
          }
        }
  }
}

So what can I do to solve the problem? Many thanks!