hadoop-common-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jothi Padmanabhan (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-3514) Reduce seeks during shuffle, by inline crcs
Date Sat, 02 Aug 2008 04:40:44 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-3514?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12619196#action_12619196
] 

Jothi Padmanabhan commented on HADOOP-3514:
-------------------------------------------

It is not actually 'checksum per record', but more of 'checksum per file'. To be more precise,
it has a checksum for the all bytes written between the creation and close of the ChecksumOutputStream,
This utility could  be used by anyone as long as they need one checksum per file and that
file is written sequentially (and in one shot) and read sequentially. Agree?

> Reduce seeks during shuffle, by inline crcs
> -------------------------------------------
>
>                 Key: HADOOP-3514
>                 URL: https://issues.apache.org/jira/browse/HADOOP-3514
>             Project: Hadoop Core
>          Issue Type: Improvement
>          Components: mapred
>    Affects Versions: 0.18.0
>            Reporter: Devaraj Das
>            Assignee: Jothi Padmanabhan
>             Fix For: 0.19.0
>
>         Attachments: hadoop-3514-v1.patch, hadoop-3514-v2.patch, hadoop-3514.patch
>
>
> The number of seeks can be reduced by half in the iFile if we move the crc into the iFile
rather than having a separate file.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message