Bug 182296 Crosstab - non-numeric measures
Feature request. Looking at the 2.2.M6 release, it seems that measures (the fields that can be in the matrix part of the output) need to be numeric. I looked at the spec documents and it seems there is no requirement for non-numeric measures
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/olap/data/util/DiskIndex.java
*/
	private IDiskArray writeLeafNode( IDiskArray sortedKeyArray, int interval )
			throws IOException
	{
		BufferedPrimitiveDiskArray offset = new BufferedPrimitiveDiskArray( Constants.LIST_BUFFER_SIZE );
		for ( int i = 0; i < sortedKeyArray.size( ); i++ )
		{
			if ( i % interval == 0 )
			{
				offset.add( new Integer( (int) documentObject.getFilePointer( ) ) );
			}
			offsetDocumentObject.writeInt( (int) documentObject.getFilePointer( ) );
			writeKeyObject( (IndexKey) sortedKeyArray.get( i ) );
		}
		return offset;
	}
	/**
	 * 
	 * @param sortedKeyArray
	 * @param startOffset
	 * @param level
	 * @param sonLevelTotalNumber
	 * @return
	 * @throws IOException
	 */
	private IDiskArray writeNonLeafNode( IDiskArray sortedKeyArray,
			IDiskArray startOffset, int level, int sonLevelTotalNumber )
			throws IOException
	{
		int interval = pow( degree, level );