title: Performance when using a filter and Instr in a MDX query
body: <p>I have an MDX query of the following form, which I am using with ActivePivot. I need to filter the results (in my on rows), by the presence of a <em>part</em> of string in another dimension (columns):</p>
  
  <pre><code>SELECT
  NON EMPTY Hierarchize({[CODE].[CODE].Members}) ON ROWS,
  NON EMPTY Hierarchize({Filter([RELEVANCE].Members, InStr([RELEVANCE].CurrentMember.Name, "n/a") &gt; 0)}) ON COLUMNS
  FROM [CUBE]
  WHERE ([Measures].[contributors.COUNT])
  </code></pre>
  
  <p>The performance of this query is very poor with the filter/instr. I think I can understand that in that it presumably 'scans' through all of the members.</p>
  
  <p>Is there another way to acheive what I want, but with better performance.</p>
  
  <p>Thanks</p>