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Yiqun Lin commented on HDFS-14986: ---------------------------------- Comment makes sense to me. I have minor suggestion for {{shouldInitRefresh}}. The meaning of shouldInitRefresh should be that 'should do init refresh operation', so the default value should be true rather than false. So I prefer to change this and add comment: {code} void init() { if (used.get() < 0) { used.set(0); // Skip initial refresh operation, so we need to do first refresh // operation immediately in refresh thread. + if (!shouldInitRefresh) { + initRefeshThread(true); + return; + } refresh(); } + initRefeshThread(false); + } {code} Can we move this method into CachingGetSpaceUsed? The variable is under CachingGetSpaceUsed, it will be better also put the set operation in this class and let sub-classes to use this. {code} + /** + * Reset that if we need to do the initial refresh. + * @param shouldInitRefresh The flag value to set. + */ + protected void setShouldInitRefresh(boolean shouldInitRefresh) { + this.shouldInitRefresh = shouldInitRefresh; + } {code} > ReplicaCachingGetSpaceUsed throws ConcurrentModificationException > ------------------------------------------------------------------ > > Key: HDFS-14986 > URL: https://issues.apache.org/jira/browse/HDFS-14986 > Project: Hadoop HDFS > Issue Type: Bug > Components: datanode, performance > Reporter: Ryan Wu > Assignee: Aiphago > Priority: Major > Attachments: HDFS-14986.001.patch, HDFS-14986.002.patch, > HDFS-14986.003.patch, HDFS-14986.004.patch > > > Running DU across lots of disks is very expensive . We applied the patch > HDFS-14313 to get used space from ReplicaInfo in memory.However, new du > threads throw the exception > {code:java} > // 2019-11-08 18:07:13,858 ERROR > [refreshUsed-/home/vipshop/hard_disk/7/dfs/dn/current/BP-1203969992-XXXX-1450855658517] > > org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.ReplicaCachingGetSpaceUsed: > ReplicaCachingGetSpaceUsed refresh error > java.util.ConcurrentModificationException: Tree has been modified outside of > iterator > at > org.apache.hadoop.hdfs.util.FoldedTreeSet$TreeSetIterator.checkForModification(FoldedTreeSet.java:311) > > at > org.apache.hadoop.hdfs.util.FoldedTreeSet$TreeSetIterator.hasNext(FoldedTreeSet.java:256) > > at java.util.AbstractCollection.addAll(AbstractCollection.java:343) > at java.util.HashSet.<init>(HashSet.java:120) > at > org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl.deepCopyReplica(FsDatasetImpl.java:1052) > > at > org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.ReplicaCachingGetSpaceUsed.refresh(ReplicaCachingGetSpaceUsed.java:73) > > at > org.apache.hadoop.fs.CachingGetSpaceUsed$RefreshThread.run(CachingGetSpaceUsed.java:178) > > at java.lang.Thread.run(Thread.java:748) > {code} -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org