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Hadoop QA commented on HDFS-1093: --------------------------------- -1 overall. Here are the results of testing the latest attachment http://issues.apache.org/jira/secure/attachment/12448598/NNreadwriteLock_trunk_2.txt against trunk revision 959874. +1 @author. The patch does not contain any @author tags. -1 tests included. The patch doesn't appear to include any new or modified tests. Please justify why no new tests are needed for this patch. Also please list what manual steps were performed to verify this patch. +1 javadoc. The javadoc tool did not generate any warning messages. +1 javac. The applied patch does not increase the total number of javac compiler warnings. +1 findbugs. The patch does not introduce any new Findbugs warnings. +1 release audit. The applied patch does not increase the total number of release audit warnings. -1 core tests. The patch failed core unit tests. -1 contrib tests. The patch failed contrib unit tests. Test results: http://hudson.zones.apache.org/hudson/job/Hdfs-Patch-h5.grid.sp2.yahoo.net/422/testReport/ Findbugs warnings: http://hudson.zones.apache.org/hudson/job/Hdfs-Patch-h5.grid.sp2.yahoo.net/422/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html Checkstyle results: http://hudson.zones.apache.org/hudson/job/Hdfs-Patch-h5.grid.sp2.yahoo.net/422/artifact/trunk/build/test/checkstyle-errors.html Console output: http://hudson.zones.apache.org/hudson/job/Hdfs-Patch-h5.grid.sp2.yahoo.net/422/console This message is automatically generated. > Improve namenode scalability by splitting the FSNamesystem synchronized > section in a read/write lock > ---------------------------------------------------------------------------------------------------- > > Key: HDFS-1093 > URL: https://issues.apache.org/jira/browse/HDFS-1093 > Project: Hadoop HDFS > Issue Type: Improvement > Components: name-node > Reporter: dhruba borthakur > Assignee: dhruba borthakur > Attachments: NNreadwriteLock.txt, NNreadwriteLock_trunk_1.txt, > NNreadwriteLock_trunk_2.txt > > > Most critical data structures in the NameNode (NN) are protected by a > syncronized methods in the FSNamesystem class. This essentially makes > critical code paths in the NN single-threaded. However, a large percentage of > the NN calls are listStatus, getBlockLocations, etc which do not change > internal data structures at all, these are read-only calls. If we change the > FSNamesystem lock to a read/write lock, many of the above operations can > occur in parallel, thus improving the scalability of the NN. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.