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https://issues.apache.org/jira/browse/PIG-1842?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12999053#comment-12999053
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Alan Gates commented on PIG-1842:
---------------------------------
>From reviewing the code it is not clear to me how this splits the XML file.
>Let's say we have an XML file that looks like:
{code}
<a>
<b>
<c>
</c>
<c1>
</c1>
</b>
</a>
<a1>
<b1>
</b1>
<b2>
</b2>
</a2>
{code}
and the split falls on line "</c1>".
How far will split 1 read? It seems like it has to read to "</a>" or else the
map processing split one will not be able to process this as a coherent
document. Yet from the setting of maxBytesReadable on line 132 it looks to me
like it won't read past the end point.
How does split 2 know where to start? I don't see any code that is telling
split 2 to fast forward to the point where split 1 ends.
All the tests pass just fine.
> Improve Scalability of the XMLLoader for large datasets such as wikipedia
> -------------------------------------------------------------------------
>
> Key: PIG-1842
> URL: https://issues.apache.org/jira/browse/PIG-1842
> Project: Pig
> Issue Type: Improvement
> Components: impl
> Affects Versions: 0.7.0, 0.8.0, 0.9.0
> Reporter: Viraj Bhat
> Assignee: Vivek Padmanabhan
> Fix For: 0.7.0, 0.8.0, 0.9.0
>
> Attachments: PIG-1842_1.patch, PIG-1842_2.patch
>
>
> The current XMLLoader for Pig, does not work well for large datasets such as
> the wikipedia dataset. Each mapper reads in the entire XML file resulting in
> extermely slow run times.
> Viraj
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