hadoop-pig-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Ying He (JIRA)" <j...@apache.org>
Subject [jira] Updated: (PIG-955) Skewed join generates incorrect results
Date Fri, 11 Sep 2009 21:47:57 GMT

     [ https://issues.apache.org/jira/browse/PIG-955?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Ying He updated PIG-955:
------------------------

    Description: SkewedPartitioner doesn't the skewed keys in partition table correctly. This
can cause data loss.  (was: Fragmented replicated join has a few limitations:
 - One of the tables needs to be loaded into memory
 - Join is limited to two tables

Skewed join partitions the table and joins the records in the reduce phase. It computes a
histogram of the key space to account for skewing in the input records. Further, it adjusts
the number of reducers depending on the key distribution.

We need to implement the skewed join in pig.)

> Skewed join generates  incorrect results 
> -----------------------------------------
>
>                 Key: PIG-955
>                 URL: https://issues.apache.org/jira/browse/PIG-955
>             Project: Pig
>          Issue Type: Improvement
>            Reporter: Ying He
>         Attachments: PIG-955.patch
>
>
> SkewedPartitioner doesn't the skewed keys in partition table correctly. This can cause
data loss.

-- 
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