[DBpedia-discussion] Unexpected Error SP031 on Public Endpoint

[Paul Houle]

Hello,  I am having trouble doing queries with named graphs on the 
dbpedia public SPARQL endpoint.   I can see a large number of graphs if 
I write

SELECT DISTINCT ?g { GRAPH ?g {?s ?p ?o .}}
---

ghttp://www.openlinksw.com/schemas/virtrdf#http://www.w3.org/ns/ldp#http://dbpedia.org/sparqlhttp://dbpedia.org/DAV/http://www.w3.org/2002/07/owl#file:wikidata_to_schema_mappings.ttlhttp://dbpedia.org/schema/property_rules#dbprdf-label 
<http://dbpedia.org/dbprdf-label>http://dbpedia.org/resource/classes#http://www.ontologyportal.org/SUMO#http://www.ontologyportal.org/WordNet#b3sonto 
<http://dbpedia.org/b3sonto>b3sifp 
<http://dbpedia.org/b3sifp>urn:rules.skoshttp://www.openlinksw.com/schemas/oplweb#virtrdf-label 
<http://dbpedia.org/virtrdf-label>facets 
<http://dbpedia.org/facets>urn:virtuoso:val:acl:schemahttp://www.openlinksw.com/virtpivot/iconshttp://www.openlinksw.com/schemas/virtpivotvirtpivot-rules 
<http://dbpedia.org/virtpivot-rules>http://www.openlinksw.com/schemas/virtcxml#virtpivot-icon-test 
<http://dbpedia.org/virtpivot-icon-test>http://pivot_test_data/campsiteshttp://pivot_test_data/ski_resortshttp://www.wikidata.org 
<http://www.wikidata.org/>https://github.com/structureddynamics/UMBEL/External%20Ontologies/dbpedia-ontology.n3http://dbpedia.org 
<http://dbpedia.org/>http://people.aifb.kit.edu/ath/#DBpedia_PageRankhttp://dbpedia.org/page_linkshttp://dbpedia.org/void/http://dbpedia.org/virt_curi
----

If I try to look at a typical graph,   say

SELECT (COUNT(*) AS ?cnt) {GRAPH <http://dbpedia.org/resource/classes#> 
{?s ?p ?o .}}

Virtuoso 37000 Error SP031: SPARQL compiler: No one quad map pattern is suitable for 
GRAPH <http://dbpedia.org/resource/classes#> { ?s ?p ?o } triple at line 3
I took a look at
https://github.com/openlink/virtuoso-opensource/blob/64e20840b0db753d58f9f679eaefa1ad1e5b73fe/libsrc/Wi/sparql2sql.c#L5019
and it still is not clear to me what is going on.  Any ideas?------------------------------------------------------------------------------
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