Hdt-jena not usable with Lucene in Fuseki?

[bjonnh]

I am loading a dataset made of a graph indexed with lucene (graphb) and another graph (grapha).
I tried to use an HDT file to replace grapha (grapha_hdt).

But as soon as I load the grapha_hdt, Lucene queries stop working on graphb.

Even if I create a HDT dataset on another service, Lucene queries stops working.

As soon as I remove the HDT-only dataset or the HDT-graph from my combined dataset, Lucene queries work again.

I am using Fuseki 3.8.0 (and updated pom.xml accordingly).

There are no errors logged and I can query the HDT graph properly, as well as the Lucene-backed graph.

I'm guessing that HDTgraph doesn't really like to be in a text dataset. But it doesn't work even when it is in a separate service.

I don't know how I could query my grapha and graphb differently (I use both in my queries, looking for things from grapha into graphb)

@prefix :        <#> .
@prefix fuseki:  <http://jena.apache.org/fuseki#> .
@prefix rdf:     <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs:    <http://www.w3.org/2000/01/rdf-schema#> .
@prefix tdb2:     <http://jena.apache.org/2016/tdb#> .
@prefix ja:      <http://jena.hpl.hp.com/2005/11/Assembler#> .
@prefix text:    <http://jena.apache.org/text#> .
@prefix hdt: <http://www.rdfhdt.org/fuseki#> .

hdt:HDTGraph rdfs:subClassOf ja:Graph .

tdb2:DatasetTDB2  rdfs:subClassOf  ja:RDFDataset .

[] ja:loadClass       "org.apache.jena.query.text.TextQuery" .
[] ja:loadClass "org.rdfhdt.hdtjena.HDTGraphAssembler" .

text:TextDataset      rdfs:subClassOf   ja:RDFDataset .
text:TextIndexLucene  rdfs:subClassOf   text:TextIndex .

<#mixed> rdf:type fuseki:Service ;
    rdfs:label                      "mixed" ;
    fuseki:name                     "mixed" ;
    fuseki:serviceQuery             "query" ;
    fuseki:serviceQuery             "sparql" ;
    fuseki:serviceReadGraphStore       "get" ;
    fuseki:dataset           :indexed_textset ;    
    .


:indexed_textset rdf:type     text:TextDataset ;
    text:dataset   :mixed_dataset ;
    text:index     <#indexLucene> ;
    tdb2:unionDefaultGraph true ;
    .

:grapha a tdb2:GraphTDB2;
   tdb2:location "DB1" .


:grapha_hdt rdfs:label "RDF Graph1 from HDT file" ;
        rdf:type hdt:HDTGraph ;
	hdt:fileName "grapha.hdt" .
	
:graphb a tdb2:GraphTDB2;
  tdb2:location "DB2" .


:mixed_dataset a ja:RDFDataset;
	  ja:namedGraph
		[ ja:graphName <http://grapha>;
# Switching to grapha make it work
#		  ja:graph :grapha ; ];
		  ja:graph :grapha_hdt ; ];
  	  ja:namedGraph
		[ ja:graphName <http://graphb>;
		  ja:graph :graphb ; ];
	  tdb2:unionDefaultGraph true;
	  .


# Text index description
<#indexLucene> a text:TextIndexLucene ;
    text:directory <file:DB2_index> ;
    text:entityMap <#entMap> ;
    text:storeValues true ; 
    text:analyzer [ a text:StandardAnalyzer ] ;
    text:queryAnalyzer [ a text:KeywordAnalyzer ] ;
    text:queryParser text:AnalyzingQueryParser ;
    text:multilingualSupport true ;
 .


<#entMap> a text:EntityMap ;
    text:defaultField     "label" ;
    text:entityField      "uri" ;
    text:uidField         "uid" ;
    text:langField        "lang" ;
    text:graphField       "graph" ;
    text:map (
         [ text:field "label" ; 
           text:predicate rdfs:label ]
         ) .