I have no experience with the specific solution described in the mailing list, but during my last research in his field I came across Solr Bobo Browse . It also supports hierarchical cutting and seems quite mature.
Solr, , . , category.
XML- :
<field name="category" type="string"
indexed="true" stored="true" multiValued="true" />
, , , :
<category>1_sport</category>
<category>2_watersport</category>
<category>3_scuba_diving</category>
.