title: Why is my timestamp range query returning nothing
body: <p>I'm using elasticsearch open distro in order to create an alert system. But I have one issue with my elasticsearch query:</p>
  
  <pre><code>"search": {
                  "indices": ["test_alert"],
                  "query": {
                      "size": 3,
                      "aggregations": {},
                      "query": {
                          "bool": {
                              "filter": {
                                  "range": {
                                      "@timestamp": {
                                          "gte": "now-1h",
                                          "lte": "now",
                                          "format": "epoch_second"
                                      }
                                  }
                              }
                          }
                      }
                  }
              }
  </code></pre>
  
  <p>This is the query I use in my open-distro monitor. The problem is the <code>now-1h</code> doesn't seem to work, I always get an empty result. I tried with raw timestamps (in order to match and get results) and it worked well. I don't understand why the range is not working at all when I'm using <code>now-1h</code>.</p>
  
  <p>Here is my mapping:</p>
  
  <pre><code>properties": {
      "timestamp": {
          "type": "date",
          "format": "epoch_second"
      },
      "value": {
          "type": "long"
      }
  }
  </code></pre>
  
  <p>Thanks for your help !</p>