ElasticSearch aggs returns 10 buckets only

Question

I am running an aggs query and specifying the size of 100, but ES only returns 10 buckets back. Why? What am I missing?

{   
  "size": 100
   ,"query": {
      "bool": {
        "must": [
          { "term": {"app": "cnn"} }
        ]
      }
    }
   ,"aggs": {
    "unique_client": {
      "terms": {"field": "client"}    
      }     
    }
}

Answer 1

Set the top size parameter to zero to signify that it is an aggregation. The number of buckets returned is set by specifying the size INSIDE the terms aggregation braces.

{   
  "size": 0
   ,"query": {
      "bool": {
        "must": [
          { "term": {"app": "cnn"} }
        ]
      }
    }
   ,"aggs": {
    "unique_client": {
      "terms": {
        "field": "client",
        "size" : 100
      }
     }     
    }
}

If you set it to 0 the value will default to Integer.MAX_VALUE

Answer 2

outer size is for total number of documents you get back for your query, so size = 100 returns 100 documents, for getting 100 aggregations bucket, specify size inside your unique_client aggs like this

{   
  "size": 0
   ,"query": {
      "bool": {
        "must": [
          { "term": {"app": "cnn"} }
        ]
      }
    }
   ,"aggs": {
    "unique_client": {
      "terms": {"field": "client"},
      "size" : 100
      }     
    }
}

By Default size of aggregations is 10, that is why you get 10 results, I have made outer size = 0 to get only aggregations.