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https://issues.apache.org/jira/browse/HDFS-14366?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16791219#comment-16791219
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Hadoop QA commented on HDFS-14366:
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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
13s{color} | {color:blue} Docker mode activated. {color} |
|| || || || {color:brown} Prechecks {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:red}-1{color} | {color:red} test4tests {color} | {color:red} 0m
0s{color} | {color:red} 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. {color} |
|| || || || {color:brown} trunk Compile Tests {color} ||
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 16m
16s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m
55s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
50s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m
3s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} shadedclient {color} | {color:green}
11m 53s{color} | {color:green} branch has no errors when building and testing
our client artifacts. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 2m
1s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m
48s{color} | {color:green} trunk passed {color} |
|| || || || {color:brown} Patch Compile Tests {color} ||
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 0m
57s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m
54s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 0m
54s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
43s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 0m
57s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m
0s{color} | {color:green} The patch has no whitespace issues. {color} |
| {color:green}+1{color} | {color:green} shadedclient {color} | {color:green}
11m 15s{color} | {color:green} patch has no errors when building and testing
our client artifacts. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 2m
3s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m
50s{color} | {color:green} the patch passed {color} |
|| || || || {color:brown} Other Tests {color} ||
| {color:red}-1{color} | {color:red} unit {color} | {color:red} 77m 47s{color}
| {color:red} hadoop-hdfs in the patch failed. {color} |
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m
38s{color} | {color:green} The patch does not generate ASF License warnings.
{color} |
| {color:black}{color} | {color:black} {color} | {color:black}129m 59s{color} |
{color:black} {color} |
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|| Reason || Tests ||
| Failed junit tests | hadoop.hdfs.TestReconstructStripedFileWithRandomECPolicy
|
| | hadoop.hdfs.web.TestWebHdfsTimeouts |
| | hadoop.hdfs.server.datanode.TestNNHandlesCombinedBlockReport |
| | hadoop.hdfs.TestSafeModeWithStripedFileWithRandomECPolicy |
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|| Subsystem || Report/Notes ||
| Docker | Client=17.05.0-ce Server=17.05.0-ce Image:yetus/hadoop:8f97d6f |
| JIRA Issue | HDFS-14366 |
| JIRA Patch URL |
https://issues.apache.org/jira/secure/attachment/12962229/HDFS-14366.001.patch |
| Optional Tests | dupname asflicense compile javac javadoc mvninstall
mvnsite unit shadedclient findbugs checkstyle |
| uname | Linux 915c6d62c138 4.4.0-139-generic #165-Ubuntu SMP Wed Oct 24
10:58:50 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux |
| Build tool | maven |
| Personality | /testptch/patchprocess/precommit/personality/provided.sh |
| git revision | trunk / 67cc24a |
| maven | version: Apache Maven 3.3.9 |
| Default Java | 1.8.0_191 |
| findbugs | v3.1.0-RC1 |
| unit |
https://builds.apache.org/job/PreCommit-HDFS-Build/26461/artifact/out/patch-unit-hadoop-hdfs-project_hadoop-hdfs.txt
|
| Test Results |
https://builds.apache.org/job/PreCommit-HDFS-Build/26461/testReport/ |
| Max. process+thread count | 4351 (vs. ulimit of 10000) |
| modules | C: hadoop-hdfs-project/hadoop-hdfs U:
hadoop-hdfs-project/hadoop-hdfs |
| Console output |
https://builds.apache.org/job/PreCommit-HDFS-Build/26461/console |
| Powered by | Apache Yetus 0.8.0 http://yetus.apache.org |
This message was automatically generated.
> Improve HDFS append performance
> -------------------------------
>
> Key: HDFS-14366
> URL: https://issues.apache.org/jira/browse/HDFS-14366
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
> Affects Versions: 2.8.2
> Reporter: Chao Sun
> Assignee: Chao Sun
> Priority: Major
> Attachments: HDFS-14366.000.patch, HDFS-14366.001.patch,
> append-flamegraph.png
>
>
> In our HDFS cluster we observed that {{append}} operation can take as much as
> 10X write lock time than other write operations. By collecting flamegraph on
> the namenode (see attachment: append-flamegraph.png), we found that most of
> the append call is spent on {{getNumLiveDataNodes()}}:
> {code}
> /** @return the number of live datanodes. */
> public int getNumLiveDataNodes() {
> int numLive = 0;
> synchronized (this) {
> for(DatanodeDescriptor dn : datanodeMap.values()) {
> if (!isDatanodeDead(dn) ) {
> numLive++;
> }
> }
> }
> return numLive;
> }
> {code}
> this method synchronizes on the {{DatanodeManager}} which is particularly
> expensive in large clusters since {{datanodeMap}} is being modified in many
> places such as processing DN heartbeats.
> For {{append}} operation, {{getNumLiveDataNodes()}} is invoked in
> {{isSufficientlyReplicated}}:
> {code}
> /**
> * Check if a block is replicated to at least the minimum replication.
> */
> public boolean isSufficientlyReplicated(BlockInfo b) {
> // Compare against the lesser of the minReplication and number of live
> DNs.
> final int replication =
> Math.min(minReplication, getDatanodeManager().getNumLiveDataNodes());
> return countNodes(b).liveReplicas() >= replication;
> }
> {code}
> The way that the {{replication}} is calculated is not very optimal, as it
> will call {{getNumLiveDataNodes()}} _every time_ even though usually
> {{minReplication}} is much smaller than the latter.
>
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