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From "Pradeep Kamath (JIRA)" <j...@apache.org>
Subject [jira] Updated: (PIG-953) Enable merge join in pig to work with loaders and store functions which can internally index sorted data
Date Fri, 16 Oct 2009 01:04:31 GMT

     [ https://issues.apache.org/jira/browse/PIG-953?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Pradeep Kamath updated PIG-953:
-------------------------------

    Attachment: PIG-953-5.patch

Zebra needs a global commit method to be able to build an index on the sorted zebra file.
Attaching a new patch which introduces a CommittableStoreFunc interfce with a commit() method
which extends StoreFunc. Zebra store function will extend this interface and pig will call
the commit() method on the CommittableStoreFunc at the completion of the job. While this is
not ideal and we could add commit() into StoreFunc itself, it would break existing store functions.
Also very soon, if changes in http://wiki.apache.org/pig/LoadStoreRedesignProposal are implemented,
this would change anyway - so this new interface is being introduced so that till we move
to the new interface changes recommended in the wiki we don't break existing store functions.

> Enable merge join in pig to work with loaders and store functions which can internally
index sorted data 
> ---------------------------------------------------------------------------------------------------------
>
>                 Key: PIG-953
>                 URL: https://issues.apache.org/jira/browse/PIG-953
>             Project: Pig
>          Issue Type: Improvement
>    Affects Versions: 0.3.0
>            Reporter: Pradeep Kamath
>            Assignee: Pradeep Kamath
>         Attachments: PIG-953-2.patch, PIG-953-3.patch, PIG-953-4.patch, PIG-953-5.patch,
PIG-953.patch
>
>
> Currently merge join implementation in pig includes construction of an index on sorted
data and use of that index to seek into the "right input" to efficiently perform the join
operation. Some loaders (notably the zebra loader) internally implement an index on sorted
data and can perform this seek efficiently using their index. So the use of the index needs
to be abstracted in such a way that when the loader supports indexing, pig uses it (indirectly
through the loader) and does not construct an index. 

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