Request
{
  "size": 0,
  "aggs": {
    "2": {
      "date_histogram": {
        "field": "@timestamp",
        "interval": "1h",
        "time_zone": "Europe/Berlin",
        "min_doc_count": 1
      },
      "aggs": {
        "1": {
          "avg": {
            "field": "metric_value_number"
          }
        }
      }
    }
  },
  "version": true,
  "query": {
    "bool": {
      "must": [
        {
          "query_string": {
            "query": "type:jmx AND metric_path:jvm.OperatingSystem.SystemCpuLoad",
            "analyze_wildcard": true
          }
        },
        {
          "range": {
            "@timestamp": {
              "gte": 1508166185803,
              "lte": 1508770985803,
              "format": "epoch_millis"
            }
          }
        }
      ],
      "must_not": []
    }
  },
  "_source": {
    "excludes": []
  },
  "highlight": {
    "pre_tags": [
      "@kibana-highlighted-field@"
    ],
    "post_tags": [
      "@/kibana-highlighted-field@"
    ],
    "fields": {
      "*": {
        "highlight_query": {
          "bool": {
            "must": [
              {
                "query_string": {
                  "query": "type:jmx AND metric_path:jvm.OperatingSystem.SystemCpuLoad",
                  "analyze_wildcard": true,
                  "all_fields": true
                }
              },
              {
                "range": {
                  "@timestamp": {
                    "gte": 1508166185803,
                    "lte": 1508770985803,
                    "format": "epoch_millis"
                  }
                }
              }
            ],
            "must_not": []
          }
        }
      }
    },
    "fragment_size": 2147483647
  }
}
Response
{
  "took": 7,
  "timed_out": false,
  "_shards": {
    "total": 15,
    "successful": 15,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 5266,
    "max_score": 0,
    "hits": []
  },
  "aggregations": {
    "2": {
      "buckets": [
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-19T17:00:00.000+02:00",
          "key": 1508425200000,
          "doc_count": 15
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-20T09:00:00.000+02:00",
          "key": 1508482800000,
          "doc_count": 10
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-20T10:00:00.000+02:00",
          "key": 1508486400000,
          "doc_count": 360
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-20T11:00:00.000+02:00",
          "key": 1508490000000,
          "doc_count": 359
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-20T12:00:00.000+02:00",
          "key": 1508493600000,
          "doc_count": 360
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-20T13:00:00.000+02:00",
          "key": 1508497200000,
          "doc_count": 356
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-20T14:00:00.000+02:00",
          "key": 1508500800000,
          "doc_count": 360
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-20T15:00:00.000+02:00",
          "key": 1508504400000,
          "doc_count": 359
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-20T16:00:00.000+02:00",
          "key": 1508508000000,
          "doc_count": 360
        },
        {
          "1": {
            "value": 0.00967741935483871
          },
          "key_as_string": "2017-10-20T17:00:00.000+02:00",
          "key": 1508511600000,
          "doc_count": 310
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-23T09:00:00.000+02:00",
          "key": 1508742000000,
          "doc_count": 31
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-23T10:00:00.000+02:00",
          "key": 1508745600000,
          "doc_count": 360
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-23T11:00:00.000+02:00",
          "key": 1508749200000,
          "doc_count": 360
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-23T12:00:00.000+02:00",
          "key": 1508752800000,
          "doc_count": 360
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-23T13:00:00.000+02:00",
          "key": 1508756400000,
          "doc_count": 360
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-23T14:00:00.000+02:00",
          "key": 1508760000000,
          "doc_count": 284
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-23T15:00:00.000+02:00",
          "key": 1508763600000,
          "doc_count": 284
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-23T16:00:00.000+02:00",
          "key": 1508767200000,
          "doc_count": 360
        },
        {
          "1": {
            "value": 0
          },
          "key_as_string": "2017-10-23T17:00:00.000+02:00",
          "key": 1508770800000,
          "doc_count": 18
        }
      ]
    }
  },
  "status": 200
}
For the count (Seem's normal)
Thanks for your help ! 