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Hadoop QA commented on HDFS-4953: --------------------------------- {color:red}-1 overall{color}. Here are the results of testing the latest attachment http://issues.apache.org/jira/secure/attachment/12594739/HDFS-4953.006.patch against trunk revision . {color:green}+1 @author{color}. The patch does not contain any @author tags. {color:green}+1 tests included{color}. The patch appears to include 2 new or modified test files. {color:red}-1 javac{color}. The applied patch generated 1153 javac compiler warnings (more than the trunk's current 1150 warnings). {color:green}+1 javadoc{color}. The javadoc tool did not generate any warning messages. {color:green}+1 eclipse:eclipse{color}. The patch built with eclipse:eclipse. {color:green}+1 findbugs{color}. The patch does not introduce any new Findbugs (version 1.3.9) warnings. {color:green}+1 release audit{color}. The applied patch does not increase the total number of release audit warnings. {color:red}-1 core tests{color}. The patch failed these unit tests in hadoop-common-project/hadoop-common hadoop-hdfs-project/hadoop-hdfs: org.apache.hadoop.hdfs.TestDFSShell {color:green}+1 contrib tests{color}. The patch passed contrib unit tests. Test results: https://builds.apache.org/job/PreCommit-HDFS-Build/4743//testReport/ Javac warnings: https://builds.apache.org/job/PreCommit-HDFS-Build/4743//artifact/trunk/patchprocess/diffJavacWarnings.txt Console output: https://builds.apache.org/job/PreCommit-HDFS-Build/4743//console This message is automatically generated. > enable HDFS local reads via mmap > -------------------------------- > > Key: HDFS-4953 > URL: https://issues.apache.org/jira/browse/HDFS-4953 > Project: Hadoop HDFS > Issue Type: New Feature > Affects Versions: 2.3.0 > Reporter: Colin Patrick McCabe > Assignee: Colin Patrick McCabe > Attachments: benchmark.png, HDFS-4953.001.patch, HDFS-4953.002.patch, > HDFS-4953.003.patch, HDFS-4953.004.patch, HDFS-4953.005.patch, > HDFS-4953.006.patch > > > Currently, the short-circuit local read pathway allows HDFS clients to access > files directly without going through the DataNode. However, all of these > reads involve a copy at the operating system level, since they rely on the > read() / pread() / etc family of kernel interfaces. > We would like to enable HDFS to read local files via mmap. This would enable > truly zero-copy reads. > In the initial implementation, zero-copy reads will only be performed when > checksums were disabled. Later, we can use the DataNode's cache awareness to > only perform zero-copy reads when we know that checksum has already been > verified. -- 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