cheat when all parts of count(distinct) key are binary

	}

      else // too bad, cannot cheat - there is more than one field

	{

	  cmp_arg = (void*)this;

	  compare_key = (qsort_cmp2)composite_key_cmp;

	  bool all_binary = 1;

	  Field** field, **field_end;

	  field_end = (field = table->field) + table->fields;

	  for(key_len = 0; field < field_end; ++field)

	    {

	      key_len += (*field)->field_length;

	      if(!(*field)->binary())

		all_binary = 0;

	    }

	  rec_offset = table->reclength - key_len;

	  if(all_binary)

	  {

	    compare_key = (qsort_cmp2)simple_raw_key_cmp;

	    cmp_arg = (void*)key_len;

	  }

	  else

	  {

	    compare_key = (qsort_cmp2)composite_key_cmp ;

 	    cmp_arg = (void*)this;

	  }

	}

      init_tree(&tree, min(max_heap_table_size, sortbuff_size/16),