CODEWITHSUNDEEP
javaneo4jgraph-databases
Indrajit Singh
Indrajit Singh

Reputation: 31

Getting following error "java.lang.UnsupportedOperationException:....." in neo4j

I have a use case where i need to run my stored proc in parallel thread in neo4j. I have written the stored proc and included it in the neo4j plugins. But while i am running the stored proc i am getting below error:

2016-06-24 05:45:54.683+0000 INFO  Remote interface available at http://localhost:7474/
java.lang.UnsupportedOperationException: Creating new transactions and/or spawning threads are not supported operations in store procedures.
    at org.neo4j.kernel.impl.proc.ProcedureGDBFacadeSPI.assertSameThread(ProcedureGDBFacadeSPI.java:108)
    at org.neo4j.kernel.impl.proc.ProcedureGDBFacadeSPI.isInOpenTransaction(ProcedureGDBFacadeSPI.java:124)
    at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTransaction(GraphDatabaseFacade.java:335)
    at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTx(GraphDatabaseFacade.java:330)
    at example.SearchTask.call(SearchTask.java:33)
    at example.SearchTask.call(SearchTask.java:17)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)

I have understood that in neo4j customized stored proc can not run in parallel threads.

But i am looking is there any way where i can run it in parallel.

Upvotes: 1

Views: 379

Answers (1)

Stefan Armbruster
Stefan Armbruster

Reputation: 39925

When using 

@Context
GraphDatabaseService graphDb

you'll get a wrapped GDS that does not allow for explicit transaction/thread management. If you need to do that in a procedure you have to use non-public API like this:

@Context
GraphDatabaseAPI graphDb

This one is not wrapped and therefore allows you to do all the nasty things. For a real world example see https://github.com/neo4j-contrib/neo4j-apoc-procedures/blob/master/src/main/java/apoc/periodic/Periodic.java#L26

Upvotes: 5

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