title: Logstash sql_last_value is not updating
body: <p>I wish to migrate records from one mysql table to elasticsearch by using logstash configuration. I'm checking that file logstash_jdbc_last_run_issued is not changing/updating so the sql_last_value is not changing also. When I add one record on table artifact, the index emp7 is inserting with replicating information without stopping. So it's growing and growing the index. Unless I break up the logstash process.</p>
  
  <p>Logstash configuration:</p>
  
  <pre><code>input {
   jdbc {
          jdbc_driver_library =&gt; "e:\Data\logstash\bin\mysql-connector-java-5.1.18-bin.jar"
          jdbc_driver_class =&gt; "com.mysql.jdbc.Driver"
          jdbc_connection_string =&gt; "jdbc:mysql://127.0.0.1:3306/kibana"
          jdbc_user =&gt; "userdb"
          jdbc_password =&gt; "passdb"
          last_run_metadata_path =&gt; "e:\Data\logstash\bin\logstash_jdbc_last_run_issued"
          tracking_column =&gt; "issuedDate"
          tracking_column_type =&gt; "numeric"
          use_column_value=&gt;true
          statement =&gt; "SELECT serial, name, issuedDate FROM artifact where issuedDate &gt; :sql_last_value;  "
          schedule =&gt; " * * * * * *"  
      }
  }
  output {
      elasticsearch {
          hosts =&gt; "http://127.0.0.1:9200"
          index =&gt; "emp7"
          document_type =&gt; "doc"
          user =&gt; "user"
          password =&gt; "pass"
      }
      stdout {
          codec =&gt; rubydebug
      }
  }
  </code></pre>
  
  <p>Table structure information: artifact</p>
  
  <pre><code>serial     varchar(40)
  name       varchar(40)
  issuedDate bigint(20)
  </code></pre>
  
  <p>I'm giving you logstash debug results:</p>
  
  <pre><code>[2019-12-30T11:38:46,004][INFO ][logstash.inputs.jdbc     ] (0.000000s) SELECT serial, name, issuedDate FROM artifact where issuedDate &gt; 0;
  [2019-12-30T11:38:46,004][WARN ][logstash.inputs.jdbc     ] tracking_column not found in dataset. {:tracking_column=&gt;"issuedDate"}
  </code></pre>
  
  <p>file logstash_jdbc_last_run_issued content:</p>
  
  <pre><code>--- 0
  </code></pre>
  
  <p>I'm using logstash 6.0, elasticsearch 6.0 and kibana 6.0</p>
  
  <p>My question is what is missing about logstash configuration?</p>