hadoop-common-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Milind A Bhandarkar" <mili...@yahoo-inc.com>
Subject Re: [jira] Updated: (HADOOP-3684) The data_join should allow the user to implement a customer cloning function
Date Thu, 03 Jul 2008 01:56:00 GMT
Cloning in java is broken. It is not intuitive, and volumes have been written on deep-copy
vs shallow-copy, and still joe q user does not get it.

If hadoop were to be truly "usable", can you comment on hadoop-2399, which has caused the
clone issue to come fore ?

IMHO, Hadoop-2399 is the root cause of all this. There is a better way to get the performance
advantages of Hadoop-2399 without changing the accepted semantics of java Iterator.

If that were fixed, this jira would be WONTFIX.


----- Original Message -----
From: Runping Qi (JIRA) <jira@apache.org>
To: core-dev@hadoop.apache.org <core-dev@hadoop.apache.org>
Sent: Wed Jul 02 18:44:44 2008
Subject: [jira] Updated: (HADOOP-3684) The data_join should allow the user to implement a
customer cloning function


     [ https://issues.apache.org/jira/browse/HADOOP-3684?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Runping Qi updated HADOOP-3684:
-------------------------------

    Status: Open  (was: Patch Available)

> The data_join should allow the user to implement a customer cloning function
> ----------------------------------------------------------------------------
>
>                 Key: HADOOP-3684
>                 URL: https://issues.apache.org/jira/browse/HADOOP-3684
>             Project: Hadoop Core
>          Issue Type: Bug
>          Components: mapred
>            Reporter: Runping Qi
>             Fix For: 0.19.0
>
>         Attachments: H-3684.txt
>
>
> Currently, the framework uses serialization/deserialization to clone the values passed
to the resuce function.
> This amounts to a very heavy weight deep copy of the value objects.
> That is way too expensive. Although that may be a generic way to work for all possible
value classes, thus good as a default way,
> the framework should allow the user to implemet an application specific yet efficient
cloning function.
>  

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

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message