incubator-crunch-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Josh Wills (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CRUNCH-57) Add a length function to PCollection
Date Wed, 05 Sep 2012 21:31:07 GMT

    [ https://issues.apache.org/jira/browse/CRUNCH-57?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13449159#comment-13449159
] 

Josh Wills commented on CRUNCH-57:
----------------------------------

My only quibble is that we force the materialization of the length() when the method is called,
which is different than most of our other methods which don't actually run the MR and return
the result until the client requests that we read it. Do we want something here like a Future
or a Scala option instance?
                
> Add a length function to PCollection
> ------------------------------------
>
>                 Key: CRUNCH-57
>                 URL: https://issues.apache.org/jira/browse/CRUNCH-57
>             Project: Crunch
>          Issue Type: New Feature
>          Components: Core
>    Affects Versions: 0.3.0
>            Reporter: Kiyan Ahmadizadeh
>            Assignee: Josh Wills
>         Attachments: CRUNCH-57.patch
>
>
> Sometimes it's useful and interesting to compute the number of elements in a PCollection.
>  
> For example, suppose there was an initial PCollection that was then filtered into another.
 If I'm interested in how many elements of the original PCollection matched the filter, I'll
have to write extra code to compute this.
> PCollections should have a length method that, when called, computes the number of elements
in the PCollection and returns the result. 

--
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