Elasticsearch 2.x sort with missing value treated as 0.0

Question

According to mapping the field I'm sorting on is of type double I was expecting the sort to treat missing values as 0 since I have some negative values which I expect to go below missing ones. (Currently missing goes below negative)

How do I achieve this?

Answer 1

You seem to describe that missing, or null values should be handled as 0 values. If you do not need to be able to distinguish them from actual '0' values, you can use a null_value, see the manual

If you do, in another situation, have to distinguish them, you might need to add a flag or something (so a second field) to actually say "but this was actually missing", but that's really depending on your usecase

a quick example:

PUT test
{
  "mappings": {
    "my_type": {
      "properties": {
        "status_code": {
          "type":       "integer",
          "null_value": 0 
        }
      }
    }
  }
}

PUT test/my_type/1
{
  "status_code": null
}
PUT test/my_type/2
{
  "status_code": -1
}
PUT test/my_type/3
{
  "status_code": 1
}

GET test/my_type/_search
{
    sort" : [
        { "status_code" : "desc" },
    ]
}

This will return the documents in order 2, 1, 3 as expected