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From "Shravan Matthur Narayanamurthy (JIRA)" <j...@apache.org>
Subject [jira] Commented: (PIG-158) Rework logical plan
Date Thu, 03 Apr 2008 17:26:24 GMT

    [ https://issues.apache.org/jira/browse/PIG-158?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12585197#action_12585197
] 

Shravan Matthur Narayanamurthy commented on PIG-158:
----------------------------------------------------

I thought Santosh was mentioning the same approach that I used and hence said that what Pi
suggested looks similar.

I use the same plans within operators approach on the physical side and everything is an operator
for me as well :)

However, while implementing the physical to mapreduce translation, I have found the visitor
pattern to be more constraining than useful. I was wondering if the visitor pattern is the
right pattern to use for all our needs. In the worst case we would have to maintain much of
the state the java compiler maintains for recursive calls. Also in many cases, the tasks that
we do for each different operator tends to be the same.

So my point is just that we should not to get stuck with the visitor pattern. May be simple
recursion has an elegant answer.

@Alan:
I am not very clear as to how the Walker/Visitor thingy interacts/works. 
Should f.getComp()... be replaced by w.visit()?

If you pop the walker out of the stack once you are done visiting the nested plan, how are
you maintaining state across visitations of the nested plan?

> Rework logical plan
> -------------------
>
>                 Key: PIG-158
>                 URL: https://issues.apache.org/jira/browse/PIG-158
>             Project: Pig
>          Issue Type: Sub-task
>          Components: impl
>            Reporter: Alan Gates
>            Assignee: Alan Gates
>         Attachments: logical_operators.patch, logical_operators_rev_1.patch, logical_operators_rev_2.patch,
logical_operators_rev_3.patch
>
>
> Rework the logical plan in line with http://wiki.apache.org/pig/PigExecutionModel

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