[jira] Commented: (HADOOP-6467) Performance improvement for liststatus on directories in hadoop archives.

["Tsz Wo (Nicholas), SZE (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-6467?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12830401#action_12830401 ] 

Tsz Wo (Nicholas), SZE commented on HADOOP-6467:
------------------------------------------------

Ran WordCount on 10^5 files.  The one on har took ~1 hour while the one on hdfs took ~5 mins.

- WordCount on har files
{noformat}
-bash-3.1$ time hadoop ${WC_CMD} ${HAR_FULL}/${DIR} ${TT_WC}
10/02/06 00:07:17 INFO input.FileInputFormat: Total input paths to process : 100000
10/02/06 00:07:17 INFO lzo.GPLNativeCodeLoader: Loaded native gpl library
10/02/06 00:07:17 INFO lzo.LzoCodec: Successfully loaded & initialized native-lzo library
10/02/06 00:35:28 INFO mapred.JobClient: Running job: job_201002042035_5217
10/02/06 00:35:29 INFO mapred.JobClient:  map 0% reduce 0%
...
10/02/06 00:39:26 INFO mapred.JobClient:  map 99% reduce 31%
...
10/02/06 00:39:49 INFO mapred.JobClient:     Reduce input records=17193

real    57m26.291s
user    21m49.516s
sys     4m58.084s
{noformat}

- WordCount on hdfs files
{noformat}
-bash-3.1$ time hadoop ${WC_CMD} ${DIR} ${WC_DIR}
10/02/06 01:03:44 INFO input.FileInputFormat: Total input paths to process : 100000
10/02/06 01:03:44 INFO lzo.GPLNativeCodeLoader: Loaded native gpl library
10/02/06 01:03:44 INFO lzo.LzoCodec: Successfully loaded & initialized native-lzo library
10/02/06 01:04:53 INFO mapred.JobClient: Running job: job_201002042035_5628
10/02/06 01:04:54 INFO mapred.JobClient:  map 0% reduce 0%
...
10/02/06 01:08:26 INFO mapred.JobClient:  map 100% reduce 100%
...

10/02/06 01:08:30 INFO mapred.JobClient:     Reduce input records=21949

real    4m54.531s
user    0m35.346s
sys     0m4.876s
{noformat}


> Performance improvement for liststatus on directories in hadoop archives.
> -------------------------------------------------------------------------
>
>                 Key: HADOOP-6467
>                 URL: https://issues.apache.org/jira/browse/HADOOP-6467
>             Project: Hadoop Common
>          Issue Type: Improvement
>            Reporter: Mahadev konar
>            Assignee: Mahadev konar
>             Fix For: 0.22.0
>
>         Attachments: Archives_performance.docx, Archives_performance.docx
>
>
> A liststatus call on a directory in hadoop archives leads to ( 2* number of files in directory) open calls to the namenode. This is very sub optimal and needs to be fixed to make it performant enough to be used on a daily basis. 

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