[jira] [Commented] (MAPREDUCE-6085) Facilitate processing of text files without key/value split

["Hadoop QA (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MAPREDUCE-6085?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14525614#comment-14525614 ] 

Hadoop QA commented on MAPREDUCE-6085:
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| (x) *{color:red}-1 overall{color}* |
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|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | pre-patch |  14m 32s | Pre-patch trunk compilation is healthy. |
| {color:green}+1{color} | @author |   0m  0s | The patch does not contain any @author tags. |
| {color:red}-1{color} | tests included |   0m  0s | 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:green}+1{color} | javac |   7m 31s | There were no new javac warning messages. |
| {color:green}+1{color} | javadoc |   9m 41s | There were no new javadoc warning messages. |
| {color:green}+1{color} | release audit |   0m 23s | The applied patch does not increase the total number of release audit warnings. |
| {color:green}+1{color} | checkstyle |   0m 24s | There were no new checkstyle issues. |
| {color:red}-1{color} | whitespace |   0m  0s | The patch has 1  line(s) that end in whitespace. Use git apply --whitespace=fix. |
| {color:green}+1{color} | install |   1m 33s | mvn install still works. |
| {color:green}+1{color} | eclipse:eclipse |   0m 33s | The patch built with eclipse:eclipse. |
| {color:green}+1{color} | findbugs |   0m 38s | The patch does not introduce any new Findbugs (version 2.0.3) warnings. |
| {color:green}+1{color} | tools/hadoop tests |   6m  8s | Tests passed in hadoop-streaming. |
| | |  41m 26s | |
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|| Subsystem || Report/Notes ||
| Patch URL | http://issues.apache.org/jira/secure/attachment/12668101/IdentifierResolver1.java.patch |
| Optional Tests | javadoc javac unit findbugs checkstyle |
| git revision | trunk / e8d0ee5 |
| whitespace | https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/5616/artifact/patchprocess/whitespace.txt |
| hadoop-streaming test log | https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/5616/artifact/patchprocess/testrun_hadoop-streaming.txt |
| Test Results | https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/5616/testReport/ |
| Java | 1.7.0_55 |
| uname | Linux asf909.gq1.ygridcore.net 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 |
| Console output | https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/5616/console |


This message was automatically generated.

> Facilitate processing of text files without key/value split
> -----------------------------------------------------------
>
>                 Key: MAPREDUCE-6085
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-6085
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>    Affects Versions: 2.4.1
>            Reporter: Dmitry Sivachenko
>         Attachments: IdentifierResolver1.java.patch
>
>
> There is a rather popular type of task: processing of text files line by line without splitting line to key/value pair in streaming mode.  (UNIX commands like grep, awk, etc, any filter scripts).
> By default, Hadoop streaming interface uses TextInputFormat which suites well for this task: it passes the input line itself to streaming job stdin.
> TextOutputReader class, which receives streaming job's output, splits it for key and value pair, and TextOutputFormat tries to merge this pair with separator.
> This results in extra separator appearing in the output in some cases.
> KeyOnlyTextOutputReader solves this problem: it passes the whole line as a key with null value, and TextOutputFormat correctly writes it without any separators inserted.
> I propose to add another IdentifierResolver: "keyonlytextoutput", which uses standard TextInputWriter but replaces TextOutputReader with KeyOnlyTextOutputReader).
> As a result, lines of text are never split into key/value pair and never joined back, so lines appear in the output unmodified.



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