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From "Owen O'Malley (JIRA)" <j...@apache.org>
Subject [jira] Updated: (HADOOP-5598) Implement a pure Java CRC32 calculator
Date Tue, 31 Mar 2009 16:30:50 GMT

     [ https://issues.apache.org/jira/browse/HADOOP-5598?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Owen O'Malley updated HADOOP-5598:
----------------------------------

    Description: We've seen a reducer writing 200MB to HDFS with replication = 1 spending
a long time in crc calculation. In particular, it was spending 5 seconds in crc calculation
out of a total of 6 for the write. I suspect that it is the java-jni border that is causing
us grief.  (was: We've seen single replica HDFS write spending too much of their time in crc32
calculation. On a 200 MB write, the crc it is taking 5 seconds of the 6 seconds total.)

> Implement a pure Java CRC32 calculator
> --------------------------------------
>
>                 Key: HADOOP-5598
>                 URL: https://issues.apache.org/jira/browse/HADOOP-5598
>             Project: Hadoop Core
>          Issue Type: Improvement
>          Components: dfs
>            Reporter: Owen O'Malley
>            Assignee: Owen O'Malley
>
> We've seen a reducer writing 200MB to HDFS with replication = 1 spending a long time
in crc calculation. In particular, it was spending 5 seconds in crc calculation out of a total
of 6 for the write. I suspect that it is the java-jni border that is causing us grief.

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