title: what is adjust pure negative in elastic search
body: <p>My dsl query looks like below. </p>
  
  <pre><code>{
    "query": {
      "bool": {
        "must": {
          "match_all": {}
        },
        "filter": [{
          "terms": {
            "field": {...}
          }],
          "adjust_pure_negative": "false";
        }
      }
    }
  }
  </code></pre>
  
  <p>When I change the flag <strong>adjust_pure_negative</strong> to true, I get no records and true is the default value.</p>