| Lucas_Werkmeister_WMDE created this task. Lucas_Werkmeister_WMDE added projects: Wikidata, Wikidata-Query-Service. Herald added subscribers: PokestarFan, Aklapper. Herald added a project: Discovery. |
TASK DESCRIPTION
The query for the co-author graph on Scholia sometimes fails with a NullPointerException:
... Caused by: java.util.concurrent.ExecutionException: java.lang.RuntimeException: java.util.concurrent.ExecutionException: java.lang.NullPointerException at java.util.concurrent.FutureTask.report(FutureTask.java:122) at java.util.concurrent.FutureTask.get(FutureTask.java:206) at com.bigdata.bop.controller.ServiceCallJoin$ChunkTask.doServiceCallWithConstant(ServiceCallJoin.java:351) at com.bigdata.bop.controller.ServiceCallJoin$ChunkTask.call(ServiceCallJoin.java:303) at com.bigdata.bop.controller.ServiceCallJoin$ChunkTask.call(ServiceCallJoin.java:215) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at com.bigdata.bop.engine.ChunkedRunningQuery$ChunkTask.call(ChunkedRunningQuery.java:1346) ... 8 more Caused by: java.lang.RuntimeException: java.util.concurrent.ExecutionException: java.lang.NullPointerException at com.bigdata.bop.controller.ServiceCallJoin$ChunkTask$ServiceCallTask.doServiceCall(ServiceCallJoin.java:757) at com.bigdata.bop.controller.ServiceCallJoin$ChunkTask$ServiceCallTask.call(ServiceCallJoin.java:616) at com.bigdata.bop.controller.ServiceCallJoin$ChunkTask$ServiceCallTask.call(ServiceCallJoin.java:552) at java.util.concurrent.FutureTask.run(FutureTask.java:266) ... 3 more Caused by: java.util.concurrent.ExecutionException: java.lang.NullPointerException at java.util.concurrent.FutureTask.report(FutureTask.java:122) at java.util.concurrent.FutureTask.get(FutureTask.java:192) at com.bigdata.rdf.graph.impl.GASEngine$ParallelFrontierStrategy.call(GASEngine.java:329) at com.bigdata.rdf.graph.impl.GASEngine$ParallelFrontierStrategy.call(GASEngine.java:236) at com.bigdata.rdf.graph.impl.GASContext.scatterEdges(GASContext.java:604) at com.bigdata.rdf.graph.impl.GASContext.doRound(GASContext.java:391) at com.bigdata.rdf.graph.impl.GASContext.call(GASContext.java:240) at com.bigdata.rdf.graph.impl.bd.GASService$GASServiceCall.call(GASService.java:845) at com.bigdata.rdf.graph.impl.bd.GASService$GASServiceCall.call(GASService.java:414) at com.bigdata.bop.controller.ServiceCallJoin$ChunkTask$ServiceCallTask.doBigdataServiceCall(ServiceCallJoin.java:770) at com.bigdata.bop.controller.ServiceCallJoin$ChunkTask$ServiceCallTask.doServiceCall(ServiceCallJoin.java:707) ... 6 more Caused by: java.lang.NullPointerException
The stack trace of the actual NullPointerException isn’t visible for some reason, but perhaps you can see it in the logs?
This error only seems to occur sporadically and isn’t reproducible. I just got it for the query in this gist (it’s too long for the URL shortener), but I’ve also seen it once on https://tools.wmflabs.org/scholia/authors/Q37876,Q173746, where the query is relatively small. (The query searches for connections between all mentioned authors, so the number of GAS services used is n × n / 2 if I’m not mistaken – quadratic query growth.)
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To: Lucas_Werkmeister_WMDE
Cc: Fnielsen, Aklapper, Smalyshev, Lucas_Werkmeister_WMDE, PokestarFan, GoranSMilovanovic, QZanden, EBjune, merbst, Avner, debt, Gehel, Jonas, FloNight, Xmlizer, Izno, jkroll, Wikidata-bugs, Jdouglas, aude, Tobias1984, Manybubbles, Mbch331
Cc: Fnielsen, Aklapper, Smalyshev, Lucas_Werkmeister_WMDE, PokestarFan, GoranSMilovanovic, QZanden, EBjune, merbst, Avner, debt, Gehel, Jonas, FloNight, Xmlizer, Izno, jkroll, Wikidata-bugs, Jdouglas, aude, Tobias1984, Manybubbles, Mbch331
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