http://wiki.apache.org/solr/FieldCollapsing#Known_Limitations
> Hi All,
>
> I'm in a situation where I need to perform a facet on a query with field
> collapsing.
>
> Let's say the main query is something like this
>
> title:apple&fq={!tag=sources}source_id:(33 OR
> 44)&facet=on&facet.field={!ex=sources}source_id&facet.query=source_id:(33
> OR 44)&collapse=on&collapse.field=hash_id
>
> I'd like my facet query to return the number of unique documents (based on
> the hash_id field) that are associated to either source 33 or 44
>
> Right now, the query works but the count returned is larger than expected
> since there is no collapsing performed on the facet query's result set.
>
> Is there any way of doing this? I'd like to be able to do this without
> performing a second request.
>
> Thanks
>
> NOTE: I'm using Solr 1.4.1 with patch 236
> (https://issues.apache.org/jira/browse/SOLR-236)
