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Hadoop QA commented on HDFS-767: -------------------------------- -1 overall. Here are the results of testing the latest attachment http://issues.apache.org/jira/secure/attachment/12425556/HDFS-767.patch against trunk revision 889494. +1 @author. The patch does not contain any @author tags. +1 tests included. The patch appears to include 6 new or modified tests. +1 javadoc. The javadoc tool did not generate any warning messages. -1 javac. The applied patch generated 23 javac compiler warnings (more than the trunk's current 22 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 passed core unit tests. +1 contrib tests. The patch passed contrib unit tests. Test results: http://hudson.zones.apache.org/hudson/job/Hdfs-Patch-h5.grid.sp2.yahoo.net/144/testReport/ Findbugs warnings: http://hudson.zones.apache.org/hudson/job/Hdfs-Patch-h5.grid.sp2.yahoo.net/144/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html Checkstyle results: http://hudson.zones.apache.org/hudson/job/Hdfs-Patch-h5.grid.sp2.yahoo.net/144/artifact/trunk/build/test/checkstyle-errors.html Console output: http://hudson.zones.apache.org/hudson/job/Hdfs-Patch-h5.grid.sp2.yahoo.net/144/console This message is automatically generated. > Job failure due to BlockMissingException > ---------------------------------------- > > Key: HDFS-767 > URL: https://issues.apache.org/jira/browse/HDFS-767 > Project: Hadoop HDFS > Issue Type: Improvement > Reporter: Ning Zhang > Assignee: Ning Zhang > Attachments: HDFS-767.patch > > > If a block is request by too many mappers/reducers (say, 3000) at the same > time, a BlockMissingException is thrown because it exceeds the upper limit (I > think 256 by default) of number of threads accessing the same block at the > same time. The DFSClient wil catch that exception and retry 3 times after > waiting for 3 seconds. Since the wait time is a fixed value, a lot of clients > will retry at about the same time and a large portion of them get another > failure. After 3 retries, there are about 256*4 = 1024 clients got the block. > If the number of clients are more than that, the job will fail. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.