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https://issues.apache.org/jira/browse/HDFS-12528?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16340427#comment-16340427
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genericqa commented on HDFS-12528:
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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} 15m 
42s{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:green}+1{color} | {color:green} test4tests {color} | {color:green}  0m 
 0s{color} | {color:green} The patch appears to include 1 new or modified test 
files. {color} |
|| || || || {color:brown} trunk Compile Tests {color} ||
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue}  0m 
10s{color} | {color:blue} Maven dependency ordering for branch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 18m 
18s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green}  1m 
40s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green}  0m 
48s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green}  1m 
49s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} shadedclient {color} | {color:green} 
12m 35s{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}  3m 
20s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green}  1m 
15s{color} | {color:green} trunk passed {color} |
|| || || || {color:brown} Patch Compile Tests {color} ||
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue}  0m  
8s{color} | {color:blue} Maven dependency ordering for patch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green}  1m 
36s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green}  1m 
47s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green}  1m 
47s{color} | {color:green} the patch passed {color} |
| {color:orange}-0{color} | {color:orange} checkstyle {color} | {color:orange}  
0m 42s{color} | {color:orange} hadoop-hdfs-project: The patch generated 7 new + 
90 unchanged - 1 fixed = 97 total (was 91) {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green}  1m 
39s{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 46s{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}  3m 
55s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green}  1m 
20s{color} | {color:green} the patch passed {color} |
|| || || || {color:brown} Other Tests {color} ||
| {color:green}+1{color} | {color:green} unit {color} | {color:green}  1m 
27s{color} | {color:green} hadoop-hdfs-client in the patch passed. {color} |
| {color:red}-1{color} | {color:red} unit {color} | {color:red}113m 27s{color} 
| {color:red} hadoop-hdfs in the patch failed. {color} |
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green}  0m 
25s{color} | {color:green} The patch does not generate ASF License warnings. 
{color} |
| {color:black}{color} | {color:black} {color} | {color:black}192m 57s{color} | 
{color:black} {color} |
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|| Reason || Tests ||
| Failed junit tests | hadoop.tools.TestHdfsConfigFields |
|   | hadoop.hdfs.server.datanode.TestDataNodeVolumeFailure |
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|| Subsystem || Report/Notes ||
| Docker | Client=17.05.0-ce Server=17.05.0-ce Image:yetus/hadoop:5b98639 |
| JIRA Issue | HDFS-12528 |
| JIRA Patch URL | 
https://issues.apache.org/jira/secure/attachment/12907777/HDFS-12528.01.patch |
| Optional Tests |  asflicense  compile  javac  javadoc  mvninstall  mvnsite  
unit  shadedclient  findbugs  checkstyle  |
| uname | Linux 56262eec8b2e 3.13.0-135-generic #184-Ubuntu SMP Wed Oct 18 
11:55:51 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux |
| Build tool | maven |
| Personality | /testptch/patchprocess/precommit/personality/provided.sh |
| git revision | trunk / 16be42d |
| maven | version: Apache Maven 3.3.9 |
| Default Java | 1.8.0_151 |
| findbugs | v3.1.0-RC1 |
| checkstyle | 
https://builds.apache.org/job/PreCommit-HDFS-Build/22820/artifact/out/diff-checkstyle-hadoop-hdfs-project.txt
 |
| unit | 
https://builds.apache.org/job/PreCommit-HDFS-Build/22820/artifact/out/patch-unit-hadoop-hdfs-project_hadoop-hdfs.txt
 |
|  Test Results | 
https://builds.apache.org/job/PreCommit-HDFS-Build/22820/testReport/ |
| Max. process+thread count | 2973 (vs. ulimit of 5000) |
| modules | C: hadoop-hdfs-project/hadoop-hdfs-client 
hadoop-hdfs-project/hadoop-hdfs U: hadoop-hdfs-project |
| Console output | 
https://builds.apache.org/job/PreCommit-HDFS-Build/22820/console |
| Powered by | Apache Yetus 0.8.0-SNAPSHOT   http://yetus.apache.org |


This message was automatically generated.



> Short-circuit reads unnecessarily disabled for a long time
> ----------------------------------------------------------
>
>                 Key: HDFS-12528
>                 URL: https://issues.apache.org/jira/browse/HDFS-12528
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: hdfs-client, performance
>    Affects Versions: 2.6.0
>            Reporter: Andre Araujo
>            Assignee: Xiao Chen
>            Priority: Major
>         Attachments: HDFS-12528.000.patch, HDFS-12528.01.patch
>
>
> We have scenarios where data ingestion makes use of the -appendToFile 
> operation to add new data to existing HDFS files. In these situations, we're 
> frequently running into the problem described below.
> We're using Impala to query the HDFS data with short-circuit reads (SCR) 
> enabled. After each file read, Impala "unbuffer"'s the HDFS file to reduce 
> the memory footprint. In some cases, though, Impala still keeps the HDFS file 
> handle open for reuse.
> The "unbuffer" call, however, causes the file's current block reader to be 
> closed, which makes the associated ShortCircuitReplica evictable from the 
> ShortCircuitCache. When the cluster is under load, this means that the 
> ShortCircuitReplica can be purged off the cache pretty fast, which closes the 
> file descriptor to the underlying storage file.
> That means that when Impala re-reads the file it has to re-open the storage 
> files associated with the ShortCircuitReplica's that were evicted from the 
> cache. If there were no appends to those blocks, the re-open will succeed 
> without problems. If one block was appended since the ShortCircuitReplica was 
> created, the re-open will fail with the following error:
> {code}
> Meta file for BP-810388474-172.31.113.69-1499543341726:blk_1074012183_273087 
> not found
> {code}
> This error is handled as an "unknown response" by the BlockReaderFactory [1], 
> which disables short-circuit reads for 10 minutes [2] for the client.
> These 10 minutes without SCR can have a big performance impact for the client 
> operations. In this particular case ("Meta file not found") it would suffice 
> to return null without disabling SCR. This particular block read would fall 
> back to the normal, non-short-circuited, path and other SCR requests would 
> continue to work as expected.
> It might also be interesting to be able to control how long SCR is disabled 
> for in the "unknown response" case. 10 minutes seems a bit to long and not 
> being able to change that is a problem.
> [1] 
> https://github.com/apache/hadoop/blob/f67237cbe7bc48a1b9088e990800b37529f1db2a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/client/impl/BlockReaderFactory.java#L646
> [2] 
> https://github.com/apache/hadoop/blob/f67237cbe7bc48a1b9088e990800b37529f1db2a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/shortcircuit/DomainSocketFactory.java#L97



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