How to update fields that are not opened in the source document without affecting them

Elastic Stack Elasticsearch
1

My template

{
"mappings":{"dynamic": "false","_source":{"includes":["a","b"]},"properties":{"a":{"type": "keyword"},"b":{"type": "keyword"},"c":{"type": "keyword"}}}}

PUT /your_index_name/_doc/1

{"a": "value_a","b": "value_b","c": "value_c"}

POST /your_index_name/_update/1

{"doc": {"a": "new_value_a","b": "new_value_b"}}

Although field c has not been stored yet, I hope that in this update situation, the index value of c should remain unchanged under the updated data, rather than being left blank.

2

What is exactly your issue? It is not clear if you are facing any issue.

3

You don’t need to hope, that is the documented and expected behavior! Just try it , eg in Kibana DevTools:


# 152: PUT /your_index_name/_doc/1 [201 Created]
# {"a": "value_a","b": "value_b","c": "value_c"}
{
  "_index": "your_index_name",
  "_id": "1",
  "_version": 1,
  "result": "created",
  "_shards": {
    "total": 2,
    "successful": 1,
    "failed": 0
  },
  "_seq_no": 0,
  "_primary_term": 1
}

# 154: GET /your_index_name/_doc/1 [200 OK]
{
  "_index": "your_index_name",
  "_id": "1",
  "_version": 1,
  "_seq_no": 0,
  "_primary_term": 1,
  "found": true,
  "_source": {
    "a": "value_a",
    "b": "value_b",
    "c": "value_c"
  }
}

# 155: POST /your_index_name/_update/1 [200 OK]
# {"doc": {"a": "new_value_a","b": "new_value_b"}}
{
  "_index": "your_index_name",
  "_id": "1",
  "_version": 2,
  "result": "updated",
  "_shards": {
    "total": 2,
    "successful": 1,
    "failed": 0
  },
  "_seq_no": 1,
  "_primary_term": 1
}

# 157: GET /your_index_name/_doc/1 [200 OK]
{
  "_index": "your_index_name",
  "_id": "1",
  "_version": 2,
  "_seq_no": 1,
  "_primary_term": 1,
  "found": true,
  "_source": {
    "a": "new_value_a",
    "b": "new_value_b",
    "c": "value_c"
  }
}

Essentially the doc is updated via

  • getting (current) version N of the doc
  • fields (from that doc and the POST call) are merged
  • version N+1 is stored in the index

@S-Dragon0302 Are you seeing something different?