Hi Paul,
The difference between the two queries is initial
"?item schema:about ?cbbObject." in the second one.
If you reverse the order of SERVICE and local pattern match, you may get
better execution.
{ ?item schema:about ?cbbObject.
{SELECT ?cbbObject ?cbbnr ?cbbObjectType ?cbbNaam
...
}
}
==>
{
{SELECT ?cbbObject ?cbbnr ?cbbObjectType ?cbbNaam
...
}
?item schema:about ?cbbObject.
}
Please let the list know if this helps,
Andy
On 21/02/18 08:30, Paul Hermans wrote:
Using Fuseki 3.6.0 and also Fuseki 3.4.0 with TDB backend.
Query 1 returns 1 result immediately
PREFIX dct: <http://purl.org/dc/terms/>
PREFIX schema: <http://schema.org/>
PREFIX prov: <http://www.w3.org/ns/prov#>
PREFIX dc: <http://purl.org/dc/elements/1.1/>
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
SELECT ?cbbObject ?cbbnr ?cbbObjectType ?cbbNaam
WHERE {
SERVICE <xxx> {
VALUES ?cbbnr {'00418870043670'}
?cbbObject a ?cbbObjectType;
<http://www.w3.org/2000/01/rdf-schema#label> ?cbbNaam ;
dct:identifier ?cbbnr . }}
Query 2 with the previous as a subselect runs forever.
PREFIX dct: <http://purl.org/dc/terms/>
PREFIX schema: <http://schema.org/>
PREFIX prov: <http://www.w3.org/ns/prov#>
PREFIX dc: <http://purl.org/dc/elements/1.1/>
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
SELECT *
WHERE
{ ?item schema:about ?cbbObject.
{SELECT ?cbbObject ?cbbnr ?cbbObjectType ?cbbNaam
WHERE {
SERVICE <http://lodcbbomv-on-1.vm.cumuli.be:8080/lodomv/repositories/cbb> {
VALUES ?cbbnr {'00418870043670'}
?cbbObject a ?cbbObjectType;
<http://www.w3.org/2000/01/rdf-schema#label> ?cbbNaam ;
dct:identifier ?cbbnr . }}}}
LIMIT 1
The same query in Virtuoso and Stardog returns a result within 1 sec.
What am I missing?
Kind Regards,
Paul Hermans
