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https://issues.apache.org/jira/browse/HDFS-8562?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15069459#comment-15069459
]
Hadoop QA commented on HDFS-8562:
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| (x) *{color:red}-1 overall{color}* |
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|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | {color:blue} reexec {color} | {color:blue} 0m 0s
{color} | {color:blue} Docker mode activated. {color} |
| {color:green}+1{color} | {color:green} @author {color} | {color:green} 0m 0s
{color} | {color:green} The patch does not contain any @author tags. {color} |
| {color:green}+1{color} | {color:green} test4tests {color} | {color:green} 0m
0s {color} | {color:green} The patch appears to include 5 new or modified test
files. {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 7m
29s {color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 7m 52s
{color} | {color:green} trunk passed with JDK v1.8.0_66 {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 8m 37s
{color} | {color:green} trunk passed with JDK v1.7.0_91 {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
56s {color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 2m 26s
{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
41s {color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 5m
29s {color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 2m 15s
{color} | {color:green} trunk passed with JDK v1.8.0_66 {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 3m 12s
{color} | {color:green} trunk passed with JDK v1.7.0_91 {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 2m
59s {color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 8m 10s
{color} | {color:green} the patch passed with JDK v1.8.0_66 {color} |
| {color:red}-1{color} | {color:red} javac {color} | {color:red} 18m 32s
{color} | {color:red} root-jdk1.8.0_66 with JDK v1.8.0_66 generated 2 new
issues (was 730, now 732). {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 8m 10s
{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 8m 45s
{color} | {color:green} the patch passed with JDK v1.7.0_91 {color} |
| {color:red}-1{color} | {color:red} javac {color} | {color:red} 27m 17s
{color} | {color:red} root-jdk1.7.0_91 with JDK v1.7.0_91 generated 2 new
issues (was 724, now 726). {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 8m 45s
{color} | {color:green} the patch passed {color} |
| {color:red}-1{color} | {color:red} checkstyle {color} | {color:red} 0m 58s
{color} | {color:red} Patch generated 1 new checkstyle issues in root (total
was 253, now 240). {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 2m 30s
{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m
41s {color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m
0s {color} | {color:green} Patch has no whitespace issues. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 5m
52s {color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 2m 20s
{color} | {color:green} the patch passed with JDK v1.8.0_66 {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 3m 14s
{color} | {color:green} the patch passed with JDK v1.7.0_91 {color} |
| {color:red}-1{color} | {color:red} unit {color} | {color:red} 6m 43s {color}
| {color:red} hadoop-common in the patch failed with JDK v1.8.0_66. {color} |
| {color:green}+1{color} | {color:green} unit {color} | {color:green} 0m 51s
{color} | {color:green} hadoop-hdfs-client in the patch passed with JDK
v1.8.0_66. {color} |
| {color:red}-1{color} | {color:red} unit {color} | {color:red} 58m 49s {color}
| {color:red} hadoop-hdfs in the patch failed with JDK v1.8.0_66. {color} |
| {color:red}-1{color} | {color:red} unit {color} | {color:red} 12m 58s {color}
| {color:red} hadoop-common in the patch failed with JDK v1.7.0_91. {color} |
| {color:green}+1{color} | {color:green} unit {color} | {color:green} 1m 4s
{color} | {color:green} hadoop-hdfs-client in the patch passed with JDK
v1.7.0_91. {color} |
| {color:red}-1{color} | {color:red} unit {color} | {color:red} 51m 53s {color}
| {color:red} hadoop-hdfs in the patch failed with JDK v1.7.0_91. {color} |
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m
26s {color} | {color:green} Patch does not generate ASF License warnings.
{color} |
| {color:black}{color} | {color:black} {color} | {color:black} 208m 46s {color}
| {color:black} {color} |
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|| Reason || Tests ||
| JDK v1.8.0_66 Failed junit tests | hadoop.fs.shell.TestCopyPreserveFlag |
| | hadoop.metrics2.impl.TestGangliaMetrics |
| | hadoop.hdfs.server.datanode.TestFsDatasetCache |
| | hadoop.hdfs.server.namenode.TestNNThroughputBenchmark |
| | hadoop.hdfs.server.datanode.TestBlockReplacement |
| | hadoop.hdfs.server.datanode.TestBlockScanner |
| | hadoop.hdfs.server.blockmanagement.TestReplicationPolicyConsiderLoad |
| JDK v1.7.0_91 Failed junit tests | hadoop.metrics2.impl.TestGangliaMetrics |
| | hadoop.hdfs.server.namenode.TestNameEditsConfigs |
| | hadoop.hdfs.server.blockmanagement.TestReplicationPolicyConsiderLoad |
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|| Subsystem || Report/Notes ||
| Docker | Image:yetus/hadoop:0ca8df7 |
| JIRA Patch URL |
https://issues.apache.org/jira/secure/attachment/12779208/HDFS-8562.004a.patch |
| JIRA Issue | HDFS-8562 |
| Optional Tests | asflicense compile javac javadoc mvninstall mvnsite
unit findbugs checkstyle |
| uname | Linux 8b1960ad28fe 3.13.0-36-lowlatency #63-Ubuntu SMP PREEMPT Wed
Sep 3 21:56:12 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux |
| Build tool | maven |
| Personality | /testptch/hadoop/patchprocess/precommit/personality/provided.sh
|
| git revision | trunk / 8c180a1 |
| findbugs | v3.0.0 |
| javac | root-jdk1.8.0_66:
https://builds.apache.org/job/PreCommit-HDFS-Build/13983/artifact/patchprocess/diff-compile-javac-root-jdk1.8.0_66.txt
|
| javac | root-jdk1.7.0_91:
https://builds.apache.org/job/PreCommit-HDFS-Build/13983/artifact/patchprocess/diff-compile-javac-root-jdk1.7.0_91.txt
|
| checkstyle |
https://builds.apache.org/job/PreCommit-HDFS-Build/13983/artifact/patchprocess/diff-checkstyle-root.txt
|
| unit |
https://builds.apache.org/job/PreCommit-HDFS-Build/13983/artifact/patchprocess/patch-unit-hadoop-common-project_hadoop-common-jdk1.8.0_66.txt
|
| unit |
https://builds.apache.org/job/PreCommit-HDFS-Build/13983/artifact/patchprocess/patch-unit-hadoop-hdfs-project_hadoop-hdfs-jdk1.8.0_66.txt
|
| unit |
https://builds.apache.org/job/PreCommit-HDFS-Build/13983/artifact/patchprocess/patch-unit-hadoop-common-project_hadoop-common-jdk1.7.0_91.txt
|
| unit |
https://builds.apache.org/job/PreCommit-HDFS-Build/13983/artifact/patchprocess/patch-unit-hadoop-hdfs-project_hadoop-hdfs-jdk1.7.0_91.txt
|
| unit test logs |
https://builds.apache.org/job/PreCommit-HDFS-Build/13983/artifact/patchprocess/patch-unit-hadoop-common-project_hadoop-common-jdk1.8.0_66.txt
https://builds.apache.org/job/PreCommit-HDFS-Build/13983/artifact/patchprocess/patch-unit-hadoop-hdfs-project_hadoop-hdfs-jdk1.8.0_66.txt
https://builds.apache.org/job/PreCommit-HDFS-Build/13983/artifact/patchprocess/patch-unit-hadoop-common-project_hadoop-common-jdk1.7.0_91.txt
https://builds.apache.org/job/PreCommit-HDFS-Build/13983/artifact/patchprocess/patch-unit-hadoop-hdfs-project_hadoop-hdfs-jdk1.7.0_91.txt
|
| JDK v1.7.0_91 Test Results |
https://builds.apache.org/job/PreCommit-HDFS-Build/13983/testReport/ |
| modules | C: hadoop-common-project/hadoop-common
hadoop-hdfs-project/hadoop-hdfs hadoop-hdfs-project/hadoop-hdfs-client U: . |
| Max memory used | 76MB |
| Powered by | Apache Yetus 0.2.0-SNAPSHOT http://yetus.apache.org |
| Console output |
https://builds.apache.org/job/PreCommit-HDFS-Build/13983/console |
This message was automatically generated.
> HDFS Performance is impacted by FileInputStream Finalizer
> ---------------------------------------------------------
>
> Key: HDFS-8562
> URL: https://issues.apache.org/jira/browse/HDFS-8562
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: datanode, performance
> Affects Versions: 2.5.0
> Environment: Impact any application that uses HDFS
> Reporter: Yanping Wang
> Attachments: HDFS-8562.002b.patch, HDFS-8562.003a.patch,
> HDFS-8562.003b.patch, HDFS-8562.004a.patch, HDFS-8562.01.patch
>
>
> While running HBase using HDFS as datanodes, we noticed excessive high GC
> pause spikes. For example with jdk8 update 40 and G1 collector, we saw
> datanode GC pauses spiked toward 160 milliseconds while they should be around
> 20 milliseconds.
> We tracked down to GC logs and found those long GC pauses were devoted to
> process high number of final references.
> For example, this Young GC:
> 2715.501: [GC pause (G1 Evacuation Pause) (young) 0.1529017 secs]
> 2715.572: [SoftReference, 0 refs, 0.0001034 secs]
> 2715.572: [WeakReference, 0 refs, 0.0000123 secs]
> 2715.572: [FinalReference, 8292 refs, 0.0748194 secs]
> 2715.647: [PhantomReference, 0 refs, 160 refs, 0.0001333 secs]
> 2715.647: [JNI Weak Reference, 0.0000140 secs]
> [Ref Proc: 122.3 ms]
> [Eden: 910.0M(910.0M)->0.0B(911.0M) Survivors: 11.0M->10.0M Heap:
> 951.1M(1536.0M)->40.2M(1536.0M)]
> [Times: user=0.47 sys=0.01, real=0.15 secs]
> This young GC took 152.9 milliseconds STW pause, while spent 122.3
> milliseconds in Ref Proc, which processed 8292 FinalReference in 74.8
> milliseconds plus some overhead.
> We used JFR and JMAP with Memory Analyzer to track down and found those
> FinalReference were all from FileInputStream. We checked HDFS code and saw
> the use of the FileInputStream in datanode:
> https://apache.googlesource.com/hadoop-common/+/refs/heads/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/MappableBlock.java
> {code}
> 1. public static MappableBlock load(long length,
> 2. FileInputStream blockIn, FileInputStream metaIn,
> 3. String blockFileName) throws IOException {
> 4. MappableBlock mappableBlock = null;
> 5. MappedByteBuffer mmap = null;
> 6. FileChannel blockChannel = null;
> 7. try {
> 8. blockChannel = blockIn.getChannel();
> 9. if (blockChannel == null) {
> 10. throw new IOException("Block InputStream has no FileChannel.");
> 11. }
> 12. mmap = blockChannel.map(MapMode.READ_ONLY, 0, length);
> 13. NativeIO.POSIX.getCacheManipulator().mlock(blockFileName, mmap, length);
> 14. verifyChecksum(length, metaIn, blockChannel, blockFileName);
> 15. mappableBlock = new MappableBlock(mmap, length);
> 16. } finally {
> 17. IOUtils.closeQuietly(blockChannel);
> 18. if (mappableBlock == null) {
> 19. if (mmap != null) {
> 20. NativeIO.POSIX.munmap(mmap); // unmapping also unlocks
> 21. }
> 22. }
> 23. }
> 24. return mappableBlock;
> 25. }
> {code}
> We looked up
> https://docs.oracle.com/javase/7/docs/api/java/io/FileInputStream.html and
> http://hg.openjdk.java.net/jdk7/jdk7/jdk/file/23bdcede4e39/src/share/classes/java/io/FileInputStream.java
> and noticed FileInputStream relies on the Finalizer to release its resource.
> When a class that has a finalizer created, an entry for that class instance
> is put on a queue in the JVM so the JVM knows it has a finalizer that needs
> to be executed.
> The current issue is: even with programmers do call close() after using
> FileInputStream, its finalize() method will still be called. In other words,
> still get the side effect of the FinalReference being registered at
> FileInputStream allocation time, and also reference processing to reclaim the
> FinalReference during GC (any GC solution has to deal with this).
> We can imagine When running industry deployment HDFS, millions of files could
> be opened and closed which resulted in a very large number of finalizers
> being registered and subsequently being executed. That could cause very long
> GC pause times.
> We tried to use Files.newInputStream() to replace FileInputStream, but it was
> clear we could not replace FileInputStream in
> hdfs/server/datanode/fsdataset/impl/MappableBlock.java
> We notified Oracle JVM team of this performance issue that impacting all Big
> Data applications using HDFS. We recommended the proper fix in Java SE
> FileInputStream. Because (1) it is really nothing wrong to use
> FileInputStream in above datanode code, (2) as the object with a finalizer is
> registered with finalizer list within the JVM at object allocation time, if
> someone makes an explicit call to close or free the resources that are to be
> done in the finalizer, then the finalizer should be pulled off the internal
> JVM’s finalizer list. That will release the JVM from having to treat the
> object as special because it has a finalizer, i.e. no need for GC to execute
> the finalizer as part of Reference Processing.
> As the java fix involves both JVM code and Java SE code, it might take time
> for the full solution to be available in future JDK releases. We would like
> to file his JIRA to notify Big Data, HDFS community to aware this issue while
> using HDFS and while writing code using FileInputStream
> One alternative is to use Files.newInputStream() to substitute
> FileInputStream if it is possible. File.newInputStream() will give an
> InputStream and do so in a manner that does not include a finalizer.
> We welcome HDFS community to discuss this issue and see if there are
> additional ideas to solve this problem.
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