sqoop-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jarek Jarcec Cecho (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (SQOOP-603) Support small intervals in IntegerSplitter implementation
Date Thu, 20 Sep 2012 19:39:08 GMT

    [ https://issues.apache.org/jira/browse/SQOOP-603?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13459882#comment-13459882
] 

Jarek Jarcec Cecho commented on SQOOP-603:
------------------------------------------

Och now I see your issue. Applying prefixed patches is actually quite simple. You just need
to add "-p1" to the patch command line.

The "p" stands for prefix and it means how many prefixed directories should be stripped from
start. Obviously "-p0" means "nothing should be removed" and it's the default. Specifying
"-p1" for git prefix diffs will remove this "a/" and "b/" prefixes.

Jarcec
                
> Support small intervals in IntegerSplitter implementation
> ---------------------------------------------------------
>
>                 Key: SQOOP-603
>                 URL: https://issues.apache.org/jira/browse/SQOOP-603
>             Project: Sqoop
>          Issue Type: Improvement
>    Affects Versions: 1.4.2
>            Reporter: Jarek Jarcec Cecho
>            Assignee: Jarek Jarcec Cecho
>             Fix For: 1.4.3
>
>         Attachments: SQOOP-603.patch
>
>
> IntegerSplitter is currently creating splits of following nature:
> {code}
> minimal value <= x < splitPoint1
> splitPoint1 <= x < splitPoint2
> ...
> splitPointN <= x <= maximal value
> {code}
> Please notice that upper bound is always with using condition "<" with exception of
the last split that is using condition "<=". This is perfectly fine when creating reasonable
amount of splits on very huge interval.
> This approach will however cause issues on very small intervals. For example following
splits will be created on interval [0, 5] with 5 splits:
> * 0 <= x < 1
> * 1 <= x < 2 
> * 2 <= x < 3 
> * 3 <= x < 4 
> * 4 <= x <= 5
> Notice that all splits have equal count of numbers except the last one having two numbers
- 4 and 5. This becomes very huge issue when for example user needs to create one split per
one partition as one mapper will end up with moving two partitions and thus entire job will
take twice as long as the other ones.
> Jarcec

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira

Mime
View raw message