[Wikidata-bugs] [Maniphest] [Created] T167858: hint:runFirst throws exception

[WikidataFacts]

WikidataFacts created this task. WikidataFacts added projects: Wikidata, Wikidata-Query-Service. Herald added a subscriber: Aklapper. Herald added a project: Discovery.

TASK DESCRIPTION

According to QueryHints, hint:runFirst should allow specifying that a particular join should run first in a join group, for example:

SELECT ?item WHERE {
  ?item wdt:P131* wd:Q1198. hint:Prior hint:runFirst true.
  ?item wdt:P31/wdt:P279* wd:Q387917.
}

However, it doesn’t work:

com.bigdata.rdf.sparql.ast.hints.QueryHintException: scope=Prior, name=runFirst, value=true, op=PropertyPathNode

	at com.bigdata.rdf.sparql.ast.hints.RunFirstHint.handle(RunFirstHint.java:66)
	at com.bigdata.rdf.sparql.ast.hints.RunFirstHint.handle(RunFirstHint.java:45)
	at com.bigdata.rdf.sparql.ast.optimizers.ASTQueryHintOptimizer._applyQueryHint(ASTQueryHintOptimizer.java:304)
	at com.bigdata.rdf.sparql.ast.optimizers.ASTQueryHintOptimizer.applyQueryHint(ASTQueryHintOptimizer.java:701)
	at com.bigdata.rdf.sparql.ast.optimizers.ASTQueryHintOptimizer.processGroup(ASTQueryHintOptimizer.java:419)
	at com.bigdata.rdf.sparql.ast.optimizers.ASTQueryHintOptimizer.optimize(ASTQueryHintOptimizer.java:155)
	…

I also tried "true" and "true"^^xsd:boolean as arguments, with the same result. (The last one should be identical to true AFAIK, but who knows what the optimizer does with them…)

(This example query can be made to run by completely disabling the optimizer, but in general it would be nice to have more fine-grained control over it.)

hint:runLast has the same problem.

TASK DETAIL

https://phabricator.wikimedia.org/T167858

EMAIL PREFERENCES

https://phabricator.wikimedia.org/settings/panel/emailpreferences/

To: WikidataFacts
Cc: Smalyshev, Aklapper, WikidataFacts, GoranSMilovanovic, QZanden, EBjune, merbst, Avner, debt, Gehel, Jonas, FloNight, Xmlizer, Izno, jkroll, Wikidata-bugs, Jdouglas, aude, Tobias1984, Manybubbles, Mbch331

_______________________________________________
Wikidata-bugs mailing list
Wikidata-bugs@lists.wikimedia.org
https://lists.wikimedia.org/mailman/listinfo/wikidata-bugs