hadoop-pig-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Richard Ding (JIRA)" <j...@apache.org>
Subject [jira] Commented: (PIG-627) PERFORMANCE: multi-query optimization
Date Wed, 11 Mar 2009 22:32:50 GMT

    [ https://issues.apache.org/jira/browse/PIG-627?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12681066#action_12681066
] 

Richard Ding commented on PIG-627:
----------------------------------

Thanks for reviewing the patch. These are excellent suggestions. I'll make sure that the changes
you proposed will be included in the next patch.

On exceptions,  when do we use runtime exceptions? I'm trying to use runtime exceptions to
indicate programming errors such as precondition violations or internal state errors. 

> PERFORMANCE: multi-query optimization
> -------------------------------------
>
>                 Key: PIG-627
>                 URL: https://issues.apache.org/jira/browse/PIG-627
>             Project: Pig
>          Issue Type: Improvement
>    Affects Versions: 1.0.0
>            Reporter: Olga Natkovich
>         Attachments: file_cmds-0305.patch, multi-store-0303.patch, multi-store-0304.patch,
multiquery_0223.patch, multiquery_0224.patch, multiquery_0306.patch
>
>
> Currently, if your Pig script contains multiple stores and some shared computation, Pig
will execute several independent queries. For instance:
> A = load 'data' as (a, b, c);
> B = filter A by a > 5;
> store B into 'output1';
> C = group B by b;
> store C into 'output2';
> This script will result in map-only job that generated output1 followed by a map-reduce
job that generated output2. As the resuld data is read, parsed and filetered twice which is
unnecessary and costly. 

-- 
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