title: What does return value -3 indicate when sending a JDBC bulk insert to crate.io
body: <p>I try to do Batch inserts with JDBC to a Crate instance:</p>
  
  <pre><code>    for(...) {
          statement.setLong(1, startTime);
          statement.setInt(2, i);
          ...
          statement.addBatch();
      }
  
      results = uaStatement.executeBatch();
      logger.info("Had bulk-result: " + Arrays.toString(results));
  </code></pre>
  
  <p>The resulting int[] array should contain 0 or 1 depending if the row was inserted or not. </p>
  
  <p>But I get back lots of "-3", which neither the JDBC standard nor the doc seems to define. </p>
  
  <p>It seems the rows don't get inserted when -3 is returned, but no additional error information is visible. It seems the -3 is coming directly from the Crate server and the client-side JDBC implementation just forwards this.</p>
  
  <p>This is crate 2.3.3 with JDBC driver 2.2.0</p>
  
  <pre><code>compile 'io.crate:crate-jdbc:2.2.0'
  </code></pre>
  
  <p>What does this indicate? Some problem with the sent values? </p>
  
  <pre><code>Had bulk-result: [1, 1, 1, 1, -3, -3, -3, -3, -3, -3, 1, -3, -3, -3, -3, -3, -3, ...
  </code></pre>