pivot facet query does not show nested result - solr

Question

I want to use pivoted facet query with solr to get counts of documents by specific 'type' in each 'region'. I run the following query:
http://localhost:8983/solr/alfresco/select?facet.pivot=ns:region,ns:type&facet=true&indent=on&q=TYPE:ns\:caseFile&rows=0&start=0&wt=json
I expect to see number documents of specific 'type' in each 'region'. But I get 'region' counts only:
....
"_pivot_mappings_": {
"ns:region,ns:type": "text#s__lt#{http://xxx.eu/model/1.0}region,text#s__lt#{http://xxx.eu/model/1.0}type"
},
"facet.pivot": "ns:region,ns:type",
...
"facet_counts": {
"facet_intervals": {},
"facet_pivot": {
"ns:region,ns:type": [
{
"field": "ns:region",
"count": 479,
"value": "{en}hk"
},
{
"field": "ns:region",
"count": 120,
"value": "{en}gk"
},
{
"field": "ns:region",
"count": 5,
"value": "{en}oc"
},
{
"field": "ns:region",
"count": 2,
"value": "{en}dep"
},
]
},
"facet_queries": {},
"facet_fields": {},
"facet_heatmaps": {},
"facet_ranges": {}
},
Pivot facets are documented to produce the results I expect, but I was unable to get nested counts, like it was shown here.
Are there any limitations in document model or index itself that prevent getting results I expect? Or is the query wrong? Is there anything I can check?

Answer 1

try "group",but must be single value

Answer 2

Problem is that the fields that I wanted to use for faceting are simply not "facetable". It is not that they are not visible solr document, thats ok because fields are not stored in the index.
What I learned so far, in order to be facetable, filed should not be tokenised and it needs to have docValues="true" in solr document schema. With these changes, faceting started to work as expected. Since the solr schema is built automatically by alfresco, there is a "facetable" marker for alfresco properties(fields). Once turned on, fileds that were previously indexed and tokenized, now become Indexed, DocValues, Omit Norms, Omit Term Frequencies & Positions. Problem solved.