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https://issues.apache.org/jira/browse/PIG-1324?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13162404#comment-13162404
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Jie Li commented on PIG-1324:
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What would be the difficulty to solve this issue?
> Logical Optimizer: Nested column pruning
> ----------------------------------------
>
> Key: PIG-1324
> URL: https://issues.apache.org/jira/browse/PIG-1324
> Project: Pig
> Issue Type: Sub-task
> Components: impl
> Affects Versions: 0.7.0
> Reporter: Daniel Dai
> Assignee: Daniel Dai
>
> Currently, column pruning does not prune sub-fields inside a complex
> data-type. For example:
> A = load '1.txt' as (a0, a1, a2);
> B = group A by a0;
> C = foreach B generate group, SUM(A.a1);
> Currently, since we group A as a bag, and some part of the bag is used in the
> following statement, so none of the fields inside A can be pruned. We shall
> keep track of sub-fields and figure out a2 is not actually needed.
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