Re: Slow property graph query

[Martynas Jusevičius <ma...@atomgraph.com>]

Hi,

still interested to know why this query performs so poorly in Fuseki.
What I thought was an alternative is actually not equivalent.

On Sun, Oct 4, 2020 at 8:39 PM Martynas Jusevičius
<ma...@atomgraph.com> wrote:
>
> Hi,
>
> The following (generated) query takes 1 minute to execute over a
> dataset of 175862 quads in Fuseki 3.16.0. Isn't that slow?
>
> If I remove the SAMPLE  and the last OPTIONAL, it executes immediately.
>
> PREFIX  dct:  <http://purl.org/dc/terms/>
> PREFIX  foaf: <http://xmlns.com/foaf/0.1/>
> PREFIX  sioc: <http://rdfs.org/sioc/ns#>
>
> SELECT DISTINCT  ?thing (COUNT(DISTINCT ?child) AS
> ?countchildd14aAdAbDbAbA) (SAMPLE(?labelthingd14aAdAbDbAbA) AS
> ?labelthingd14aAdAbDbAbAsample)
> WHERE
>   { GRAPH ?childGraph
>       {   { ?child  sioc:has_parent  <https://localhost:4443/products/> }
>         UNION
>           { ?child  sioc:has_container  <https://localhost:4443/products/> }
>         ?child  a                     ?Type
>         OPTIONAL
>           { ?child  dct:title  ?title }
>         OPTIONAL
>           { ?child  foaf:primaryTopic  ?thing }
>       }
>     OPTIONAL
>       {   { ?thing
> (((((((<http://www.w3.org/2000/01/rdf-schema#label>|<http://purl.org/dc/elements/1.1/title>)|dct:title)|foaf:name)|foaf:givenName)|foaf:familyName)|sioc:name)|<http://www.w3.org/2004/02/skos/core#prefLabel>)|sioc:content
> ?labelthingd14aAdAbDbAbA }
>         UNION
>           { GRAPH ?labelthingd14aAdAbDbAbAgraph
>               { ?thing
> (((((((<http://www.w3.org/2000/01/rdf-schema#label>|<http://purl.org/dc/elements/1.1/title>)|dct:title)|foaf:name)|foaf:givenName)|foaf:familyName)|sioc:name)|<http://www.w3.org/2004/02/skos/core#prefLabel>)|sioc:content
> ?labelthingd14aAdAbDbAbA }
>           }
>       }
>   }
> GROUP BY ?thing
> ORDER BY DESC(?countchildd14aAdAbDbAbA)
>
> Martynas