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From "Chris Douglas (JIRA)" <j...@apache.org>
Subject [jira] Reopened: (HADOOP-2774) Add counters to show number of key/values that have been sorted and merged in the maps and reduces
Date Tue, 18 Nov 2008 23:53:44 GMT

     [ https://issues.apache.org/jira/browse/HADOOP-2774?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Chris Douglas reopened HADOOP-2774:
-----------------------------------


I reverted this because using a non-volatile, static long to track records written from IFile
is patently incorrect, particularly in the reduce, where there can be dozens of writers.

Also, the record count should be part of the IFile format, not stored with the index and passed
in the header.

> Add counters to show number of key/values that have been sorted and merged in the maps
and reduces
> --------------------------------------------------------------------------------------------------
>
>                 Key: HADOOP-2774
>                 URL: https://issues.apache.org/jira/browse/HADOOP-2774
>             Project: Hadoop Core
>          Issue Type: Bug
>            Reporter: Owen O'Malley
>            Assignee: Ravi Gummadi
>             Fix For: 0.20.0
>
>         Attachments: HADOOP-2774.patch, HADOOP-2774.patch
>
>
> For each *pass* of the sort and merge, I would like a count of the number of records.
So for example, if the map output 100 records and they were sorted once, the counter would
be 100. If it spilled twice and was merged together, it would be 200. Clearly in a multi-level
merge, it may not be a multiple of the number of map output records. This would let the users
easily see if they have values like io.sort.mb or io.sort.factor set too low.

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