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Hudson commented on HDFS-2751: ------------------------------ Integrated in Hadoop-Common-trunk-Commit #1560 (See [https://builds.apache.org/job/Hadoop-Common-trunk-Commit/1560/]) HDFS-2751. Datanode may incorrectly drop OS cache behind reads even for short reads. Contributed by Todd Lipcon. todd : http://svn.apache.org/viewcvs.cgi/?root=Apache-SVN&view=rev&rev=1233796 Files : * /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/datanode/BlockSender.java > Datanode drops OS cache behind reads even for short reads > --------------------------------------------------------- > > Key: HDFS-2751 > URL: https://issues.apache.org/jira/browse/HDFS-2751 > Project: Hadoop HDFS > Issue Type: Bug > Components: data-node > Affects Versions: 0.23.0, 0.24.0 > Reporter: Todd Lipcon > Assignee: Todd Lipcon > Fix For: 0.24.0, 0.23.1 > > Attachments: hdfs-2751.txt, hdfs-2751.txt > > > HDFS-2465 has some code which attempts to disable the "drop cache behind > reads" functionality when the reads are <256KB (eg HBase random access). But > this check was missing in the {{close()}} function, so it always drops cache > behind reads regardless of the size of the read. This hurts HBase random read > performance when this patch is enabled. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira