Filter elasticsearch results to contain only unique documents based on one field value

Question

All my documents have a uid field with an ID that links the document to a user. There are multiple documents with the same uid.

I want to p

Answer 1

In ElasticSearch 5.3 they added support for field collapsing. You should be able to do something like:

GET /_search
{
  "query": {
    "multi_match" : {
      "query":    "this is a test", 
      "fields": [ "subject", "message", "uid" ] 
    }
  },
  "collapse" : {
    "field" : "uid" 
  },
  "size": 20,
  "from": 100
}

The benefit of using field collapsing instead of a top hits aggregation is that you can use pagination with field collapsing.