title: BATproject error when querying monetdb database
body: <p>I'm running into issues when running the following query on a monetdb database:</p>
  
  <pre><code>SELECT
      tpuc.tbl1_col1,
      s.tbl2_col1,
      COUNT(s.tbl2_col2)
  FROM
      tbl2 AS s INNER JOIN
      tbl AS tpuc ON (s.tbl2_col2=tpuc.tbl1_col2)
  GROUP BY
      tpuc.tbl1_col1,
      s.tbl2_col1
  </code></pre>
  
  <blockquote>
    <p>Can not create object BATproject: does not match always</p>
  </blockquote>
  
  <p>tbl2 has just a little over 35mil rows and tbl1 has around 300k rows. The query runs flawlessly on a database with an identical structure but considerably less data (about a tenth) so I assume this is related to the amount of data. Does anyone have experience with this error? </p>
  
  <p>I've ran queries on larger databases than this and monetdb seems to be designed to handle more data so I'm thinking that this is maybe some sort of error on my part / data corruption. However, the error doesn't seem to be documented anywhere so every little bit of insight is appreciated.</p>
  
  <p>later edit:
  running into the same error when running simpler queries such as select group by</p>
  
  <p>Thanks</p>