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Posted to dev@kafka.apache.org by "Alexey Ozeritskiy (JIRA)" <ji...@apache.org> on 2016/12/02 13:52:58 UTC
[jira] [Commented] (KAFKA-4205) NullPointerException in
fetchOffsetsBefore
[ https://issues.apache.org/jira/browse/KAFKA-4205?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15715179#comment-15715179 ]
Alexey Ozeritskiy commented on KAFKA-4205:
------------------------------------------
We see this on 0.10.1. ~20-30 errors per day on every broker
> NullPointerException in fetchOffsetsBefore
> ------------------------------------------
>
> Key: KAFKA-4205
> URL: https://issues.apache.org/jira/browse/KAFKA-4205
> Project: Kafka
> Issue Type: Bug
> Components: core
> Affects Versions: 0.9.0.1
> Reporter: Andrew Grasso
>
> We recently observed the following error in brokers running 0.9.0.1:
> A client saw an Unkown error code in response to an offset request for TOPICX, partition 0
> The server logs look like:
> {code}
> [2016-09-21 21:26:07,143] INFO Scheduling log segment 527235760 for log TOPICX-0 for deletion. (kafka.log.Log)
> [2016-09-21 21:26:07,144] ERROR [KafkaApi-13] Error while responding to offset request (kafka.server.KafkaApis)
> java.lang.NullPointerException
> at kafka.server.KafkaApis.fetchOffsetsBefore(KafkaApis.scala:513)
> at kafka.server.KafkaApis.fetchOffsets(KafkaApis.scala:501)
> at kafka.server.KafkaApis$$anonfun$18.apply(KafkaApis.scala:461)
> at kafka.server.KafkaApis$$anonfun$18.apply(KafkaApis.scala:452)
> at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
> at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
> at scala.collection.immutable.Map$Map1.foreach(Map.scala:109)
> at scala.collection.TraversableLike$class.map(TraversableLike.scala:244)
> at scala.collection.AbstractTraversable.map(Traversable.scala:105)
> at kafka.server.KafkaApis.handleOffsetRequest(KafkaApis.scala:452)
> at kafka.server.KafkaApis.handle(KafkaApis.scala:70)
> at kafka.server.KafkaRequestHandler.run(KafkaRequestHandler.scala:60)
> at java.lang.Thread.run(Thread.java:745)
> [2016-09-21 21:27:07,143] INFO Deleting segment 527235760 from log TOPICX-0. (kafka.log.Log)
> [2016-09-21 21:27:07,263] INFO Deleting index /path/to/kafka/data/TOPICX-0/00000000000527235760.index.deleted (kafka.log.OffsetIndex)
> {code}
> I suspect a race condition between {{Log.deleteSegment}} (which takes a lock on the log) and {{KafkaApis.fetchOffsetsBefore}}, which does not take any lock. In particular, line 513 in KafkaApis looks like:
> {code:title=KafkaApis.scala|borderStyle=solid}
> 510 private def fetchOffsetsBefore(log: Log, timestamp: Long, maxNumOffsets: Int): Seq[Long] = {
> 511 val segsArray = log.logSegments.toArray
> 512 var offsetTimeArray: Array[(Long, Long)] = null
> 513 val lastSegmentHasSize = segsArray.last.size > 0;
> {code}
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