[
https://issues.apache.org/jira/browse/HDFS-16155?focusedWorklogId=642544&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-642544
]
ASF GitHub Bot logged work on HDFS-16155:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 26/Aug/21 19:30
Start Date: 26/Aug/21 19:30
Worklog Time Spent: 10m
Work Description: hadoop-yetus commented on pull request #3271:
URL: https://github.com/apache/hadoop/pull/3271#issuecomment-906684045
:confetti_ball: **+1 overall**
| Vote | Subsystem | Runtime | Logfile | Comment |
|:----:|----------:|--------:|:--------:|:-------:|
| +0 :ok: | reexec | 0m 50s | | Docker mode activated. |
|||| _ Prechecks _ |
| +1 :green_heart: | dupname | 0m 0s | | No case conflicting files
found. |
| +0 :ok: | codespell | 0m 1s | | codespell was not available. |
| +1 :green_heart: | @author | 0m 0s | | The patch does not contain
any @author tags. |
| +1 :green_heart: | test4tests | 0m 0s | | The patch appears to
include 2 new or modified test files. |
|||| _ trunk Compile Tests _ |
| +0 :ok: | mvndep | 12m 46s | | Maven dependency ordering for branch |
| +1 :green_heart: | mvninstall | 24m 30s | | trunk passed |
| +1 :green_heart: | compile | 5m 52s | | trunk passed with JDK
Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04 |
| +1 :green_heart: | compile | 5m 34s | | trunk passed with JDK
Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10 |
| +1 :green_heart: | checkstyle | 1m 15s | | trunk passed |
| +1 :green_heart: | mvnsite | 2m 27s | | trunk passed |
| +1 :green_heart: | javadoc | 1m 48s | | trunk passed with JDK
Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04 |
| +1 :green_heart: | javadoc | 2m 13s | | trunk passed with JDK
Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10 |
| +1 :green_heart: | spotbugs | 6m 26s | | trunk passed |
| +1 :green_heart: | shadedclient | 18m 38s | | branch has no errors
when building and testing our client artifacts. |
|||| _ Patch Compile Tests _ |
| +0 :ok: | mvndep | 0m 27s | | Maven dependency ordering for patch |
| +1 :green_heart: | mvninstall | 2m 29s | | the patch passed |
| +1 :green_heart: | compile | 5m 41s | | the patch passed with JDK
Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04 |
| +1 :green_heart: | javac | 5m 41s | | the patch passed |
| +1 :green_heart: | compile | 5m 7s | | the patch passed with JDK
Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10 |
| +1 :green_heart: | javac | 5m 7s | | the patch passed |
| +1 :green_heart: | blanks | 0m 0s | | The patch has no blanks
issues. |
| +1 :green_heart: | checkstyle | 1m 10s | | the patch passed |
| +1 :green_heart: | mvnsite | 2m 14s | | the patch passed |
| +1 :green_heart: | xml | 0m 2s | | The patch has no ill-formed XML
file. |
| +1 :green_heart: | javadoc | 1m 30s | | the patch passed with JDK
Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04 |
| +1 :green_heart: | javadoc | 1m 56s | | the patch passed with JDK
Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10 |
| +1 :green_heart: | spotbugs | 6m 12s | | the patch passed |
| +1 :green_heart: | shadedclient | 16m 48s | | patch has no errors
when building and testing our client artifacts. |
|||| _ Other Tests _ |
| +1 :green_heart: | unit | 2m 28s | | hadoop-hdfs-client in the patch
passed. |
| +1 :green_heart: | unit | 245m 3s | | hadoop-hdfs in the patch
passed. |
| +1 :green_heart: | asflicense | 0m 44s | | The patch does not
generate ASF License warnings. |
| | | 372m 18s | | |
| Subsystem | Report/Notes |
|----------:|:-------------|
| Docker | ClientAPI=1.41 ServerAPI=1.41 base:
https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-3271/7/artifact/out/Dockerfile
|
| GITHUB PR | https://github.com/apache/hadoop/pull/3271 |
| JIRA Issue | HDFS-16155 |
| Optional Tests | dupname asflicense compile javac javadoc mvninstall
mvnsite unit shadedclient spotbugs checkstyle codespell xml |
| uname | Linux 37c7e964f56c 4.15.0-151-generic #157-Ubuntu SMP Fri Jul 9
23:07:57 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux |
| Build tool | maven |
| Personality | dev-support/bin/hadoop.sh |
| git revision | trunk / 4e1300a8d082ded6433c90f1a8f907f355920e92 |
| Default Java | Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10 |
| Multi-JDK versions |
/usr/lib/jvm/java-11-openjdk-amd64:Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04
/usr/lib/jvm/java-8-openjdk-amd64:Private
Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10 |
| Test Results |
https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-3271/7/testReport/ |
| Max. process+thread count | 3435 (vs. ulimit of 5500) |
| modules | C: hadoop-hdfs-project/hadoop-hdfs-client
hadoop-hdfs-project/hadoop-hdfs U: hadoop-hdfs-project |
| Console output |
https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-3271/7/console |
| versions | git=2.25.1 maven=3.6.3 spotbugs=4.2.2 |
| Powered by | Apache Yetus 0.14.0-SNAPSHOT https://yetus.apache.org |
This message was automatically generated.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
Issue Time Tracking
-------------------
Worklog Id: (was: 642544)
Time Spent: 2h 20m (was: 2h 10m)
> Allow configurable exponential backoff in DFSInputStream refetchLocations
> -------------------------------------------------------------------------
>
> Key: HDFS-16155
> URL: https://issues.apache.org/jira/browse/HDFS-16155
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: dfsclient
> Reporter: Bryan Beaudreault
> Assignee: Bryan Beaudreault
> Priority: Minor
> Labels: pull-request-available
> Time Spent: 2h 20m
> Remaining Estimate: 0h
>
> The retry policy in
> [DFSInputStream#refetchLocations|https://github.com/apache/hadoop/blob/trunk/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java#L1018-L1040]
> was first written many years ago. It allows configuration of the base time
> window, but subsequent retries double in an un-configurable way. This retry
> strategy makes sense in some clusters as it's very conservative and will
> avoid DDOSing the namenode in certain systemic failure modes – for example,
> if a file is being read by a large hadoop job and the underlying blocks are
> moved by the balancer. In this case, enough datanodes would be added to the
> deadNodes list and all hadoop tasks would simultaneously try to refetch the
> blocks. The 3s doubling with random factor helps break up that stampeding
> herd.
> However, not all cluster use-cases are created equal, so there are other
> cases where a more aggressive initial backoff is preferred. For example in a
> low-latency single reader scenario. In this case, if the balancer moves
> enough blocks, the reader hits this 3s backoff which is way too long for a
> low latency use-case.
> One could configure the the window very low (10ms), but then you can hit
> other systemic failure modes which would result in readers DDOSing the
> namenode again. For example, if blocks went missing due to truly dead
> datanodes. In this case, many readers might be refetching locations for
> different files with retry backoffs like 10ms, 20ms, 40ms, etc. It takes a
> while to backoff enough to avoid impacting the namenode with that strategy.
> I suggest adding a configurable multiplier to the backoff strategy so that
> operators can tune this as they see fit for their use-case. In the above low
> latency case, one could set the base very low (say 2ms) and the multiplier
> very high (say 50). This gives an aggressive first retry that very quickly
> backs off.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
---------------------------------------------------------------------
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
