title: Elastic Logstash JDBC sqlserver insert Existing data again repeatly
body: <p>I'm using Elastic Logstash to import data from Sql-Server 2016 to elasticsearch.
  I'm using this config for logstash :</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>input {
    jdbc {
      jdbc_driver_library =&gt; "D:\Development\Elastic\elasticsearch-jdbc-2.3.4.1\lib\sqljdbc42.jar"
      jdbc_driver_class =&gt; "com.microsoft.sqlserver.jdbc.SQLServerDriver"
      jdbc_connection_string =&gt; "jdbc:sqlserver://DESKTOP-92GPVCD;databaseName=Safenat;user=user;password=pass;"
      jdbc_user =&gt; "user"
      jdbc_password =&gt; "pass"
      statement =&gt; "SELECT * from Content"
      type =&gt; "Content" 
    }
    jdbc {
      jdbc_driver_library =&gt; "D:\Development\Elastic\elasticsearch-jdbc-2.3.4.1\lib\sqljdbc42.jar"
      jdbc_driver_class =&gt; "com.microsoft.sqlserver.jdbc.SQLServerDriver"
      jdbc_connection_string =&gt; "jdbc:sqlserver://DESKTOP-92GPVCD;databaseName=Safenat;user=user;password=pass;"
      jdbc_user =&gt; "user"
      jdbc_password =&gt; "pass"
      statement =&gt; "SELECT * from Tag"
      type =&gt; "Tag" 
    }
  }
  filter {
  }
  output {
    elasticsearch {
      hosts =&gt; "http://localhost:9200"
      index =&gt; "MYINDEX"
    }
    stdout { codec =&gt; rubydebug }
  }</code></pre>
  </div>
  </div>
  </p>
  
  <p>and i use kibana to see what happend . logstash log.txt fast increse size and kibana _cat/indices also show data size increase on in my index
  I want to import every record just once . what can i do ?</p>