<p>My data is such that I want to display values for the Employee and the Supervisor for a particular record. Instead of describing it, I'll show you a rough example:</p>

<pre><code>&lt;table&gt;&lt;tr&gt;
&lt;th colspan="3"&gt;Employee&lt;/th&gt;
&lt;th colspan="3"&gt;Supervisor&lt;/th&gt;
&lt;/tr&gt;&lt;tr&gt;
&lt;th&gt;Name&lt;/th&gt;
&lt;th&gt;Last Activity&lt;/th&gt;
&lt;th&gt;Count&lt;/th&gt;
&lt;th&gt;Name&lt;/th&gt;
&lt;th&gt;Last Activity&lt;/th&gt;
&lt;th&gt;Count&lt;/th&gt;
&lt;/tr&gt;
&lt;/table&gt;
</code></pre>

<p>How can I create this for a GridView?  I essentially want 2 rows for the headings, and some of the cells should span more than one column.</p>

This is probably happening because you're trying to index too many items at once.  Make sure you're using
ranged queries
.  If you're already using ranged queries, increasing the
```
mem_limit
```
, as it suggests, may help.  The
```
merge_block_size
```
is based on
```
mem_limit
```
and the number of documents.
If you're curious as to how it generates that number, check out the source.  It's freely available.