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JichengSong updated HDFS-7592: ------------------------------ Attachment: HDFS-7592.patch > A bug in BlocksMap that cause NameNode memory leak. > ----------------------------------------------------- > > Key: HDFS-7592 > URL: https://issues.apache.org/jira/browse/HDFS-7592 > Project: Hadoop HDFS > Issue Type: Bug > Components: namenode > Affects Versions: 0.21.0 > Environment: HDFS-0.21.0 > Reporter: JichengSong > Assignee: JichengSong > Labels: BlocksMap, leak, memory > Fix For: 0.21.0 > > Attachments: HDFS-7592.patch > > > In our HDFS production environment, NameNode FGC frequently after running for > 2 months, we have to restart NameNode manually. > We dumped NameNode's Heap for objects statistics. > Before restarting NameNode: > num #instances #bytes class name > ---------------------------------------------- > 1: 59262275 3613989480 [Ljava.lang.Object; > ... > 10: 8549361 615553992 > org.apache.hadoop.hdfs.server.namenode.BlockInfoUnderConstruction > 11: 5941511 427788792 > org.apache.hadoop.hdfs.server.namenode.INodeFileUnderConstruction > After restarting NameNode: > num #instances #bytes class name > ---------------------------------------------- > 1: 44188391 2934099616 [Ljava.lang.Object; > ... > 23: 721763 51966936 > org.apache.hadoop.hdfs.server.namenode.BlockInfoUnderConstruction > 24: 620028 44642016 > org.apache.hadoop.hdfs.server.namenode.INodeFileUnderConstruction > We find the number of BlockInfoUnderConstruction is abnormally large before > restarting NameNode. > As we know, BlockInfoUnderConstruction keeps block state when the file is > being written. But the write pressure of > our cluster is far less than million/sec. We think there is a memory leak in > NameNode. > We fixed the bug as followsing patch. > --- src/java/org/apache/hadoop/hdfs/server/namenode/BlocksMap.java > (reversion 1640066) > +++ src/java/org/apache/hadoop/hdfs/server/namenode/BlocksMap.java > @@ -205,6 +205,8 @@ > DatanodeDescriptor dn = currentBlock.getDatanode(idx); > dn.replaceBlock(currentBlock, newBlock); > } > + // change to fix bug about memory leak of NameNode > + map.remove(newBlock); > // replace block in the map itself > map.put(newBlock, newBlock); -- This message was sent by Atlassian JIRA (v6.3.4#6332)