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Posted to issues@flink.apache.org by "Ufuk Celebi (JIRA)" <ji...@apache.org> on 2015/08/25 18:48:46 UTC

[jira] [Commented] (FLINK-2189) NullPointerException in MutableHashTable

    [ https://issues.apache.org/jira/browse/FLINK-2189?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14711608#comment-14711608 ] 

Ufuk Celebi commented on FLINK-2189:
------------------------------------

[~Felix Neutatz], can you still reproduce this error after the recent fix in 627f3cbcfdca8368eea6aa825cd9a45a9a0a841f?

> NullPointerException in MutableHashTable
> ----------------------------------------
>
>                 Key: FLINK-2189
>                 URL: https://issues.apache.org/jira/browse/FLINK-2189
>             Project: Flink
>          Issue Type: Bug
>          Components: Core
>            Reporter: Till Rohrmann
>
> [~Felix Neutatz] reported a {{NullPointerException}} in the {{MutableHashTable}} when running the {{ALS}} algorithm. The stack trace is the following:
> {code}
> Caused by: java.lang.NullPointerException
> 	at org.apache.flink.runtime.operators.hash.HashPartition.spillPartition(HashPartition.java:310)
> 	at org.apache.flink.runtime.operators.hash.MutableHashTable.spillPartition(MutableHashTable.java:1094)
> 	at org.apache.flink.runtime.operators.hash.MutableHashTable.insertBucketEntry(MutableHashTable.java:927)
> 	at org.apache.flink.runtime.operators.hash.MutableHashTable.buildTableFromSpilledPartition(MutableHashTable.java:783)
> 	at org.apache.flink.runtime.operators.hash.MutableHashTable.prepareNextPartition(MutableHashTable.java:508)
> 	at org.apache.flink.runtime.operators.hash.MutableHashTable.nextRecord(MutableHashTable.java:544)
> 	at org.apache.flink.runtime.operators.hash.NonReusingBuildFirstHashMatchIterator.callWithNextKey(NonReusingBuildFirstHashMatchIterator.java:104)
> 	at org.apache.flink.runtime.operators.MatchDriver.run(MatchDriver.java:173)
> 	at org.apache.flink.runtime.operators.RegularPactTask.run(RegularPactTask.java:496)
> 	at org.apache.flink.runtime.operators.RegularPactTask.invoke(RegularPactTask.java:362)
> 	at org.apache.flink.runtime.taskmanager.Task.run(Task.java:559)
> 	at java.lang.Thread.run(Thread.java:745)
> {code}
> He produced this error on his local machine with the following code:
> {code}
> implicit val env = ExecutionEnvironment.getExecutionEnvironment
> val links = MovieLensUtils.readLinks(movieLensDir + "links.csv")
> val movies = MovieLensUtils.readMovies(movieLensDir + "movies.csv")
> val ratings = MovieLensUtils.readRatings(movieLensDir + "ratings.csv")
> val tags = MovieLensUtils.readTags(movieLensDir + "tags.csv")
>           
> val ratingMatrix =  ratings.map { r => (r.userId.toInt, r.movieId.toInt, r.rating) }
> val testMatrix =  ratings.map { r => (r.userId.toInt, r.movieId.toInt) }
> val als = ALS()
>    .setIterations(10)
>    .setNumFactors(10)
>    .setBlocks(150) 
>      
> als.fit(ratingMatrix)
> val result = als.predict(testMatrix)
>      
> result.print
> val risk = als.empiricalRisk(ratingMatrix).collect().apply(0)
> println("Empirical risk: " + risk) 
> env.execute()
> {code}



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