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Hudson commented on HDFS-4879: ------------------------------ SUCCESS: Integrated in Hadoop-Yarn-trunk #325 (See [https://builds.apache.org/job/Hadoop-Yarn-trunk/325/]) HDFS-4879. Add BlockedArrayList collection to avoid CMS full GCs (Contributed by Todd Lipcon) (cmccabe: http://svn.apache.org/viewcvs.cgi/?root=Apache-SVN&view=rev&rev=1520667) * /hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt * /hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirectory.java * /hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSEditLogLoader.java * /hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java * /hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INode.java * /hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/util/ChunkedArrayList.java * /hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/util/TestChunkedArrayList.java > Add "blocked ArrayList" collection to avoid CMS full GCs > -------------------------------------------------------- > > Key: HDFS-4879 > URL: https://issues.apache.org/jira/browse/HDFS-4879 > Project: Hadoop HDFS > Issue Type: Improvement > Components: namenode > Affects Versions: 3.0.0, 2.0.4-alpha > Reporter: Todd Lipcon > Assignee: Todd Lipcon > Fix For: 2.3.0 > > Attachments: hdfs-4879.txt, hdfs-4879.txt, hdfs-4879.txt, > hdfs-4879.txt > > > We recently saw an issue where a large deletion was issued which caused 25M > blocks to be collected during {{deleteInternal}}. Currently, the list of > collected blocks is an ArrayList, meaning that we had to allocate a > contiguous 25M-entry array (~400MB). After a NN has been running for a long > amount of time, the old generation may become fragmented such that it's hard > to find a 400MB contiguous chunk of heap. > In general, we should try to design the NN such that the only large objects > are long-lived and created at startup time. We can improve this particular > case (and perhaps some others) by introducing a new List implementation which > is made of a linked list of arrays, each of which is size-limited (eg to 1MB). -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira