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From "Santhosh Srinivasan (JIRA)" <j...@apache.org>
Subject [jira] Commented: (PIG-158) Rework logical plan
Date Thu, 01 May 2008 17:20:56 GMT

    [ https://issues.apache.org/jira/browse/PIG-158?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12593587#action_12593587
] 

Santhosh Srinivasan commented on PIG-158:
-----------------------------------------

I am grouping my responses to 1, 2 and 5 together

wrt point 2, the reason for having a multimap instead of a map, generate is tied to foreach
alone and is no longer being used in the scenarios that I mentioned. Cogroup expects a list
of expression operators per input. Each expression operator is wrapped in a logical plan,
resulting in a list of logical plans per input.

LOForeach will have a nested plan and the list of logical operators will go away.

3. There is a consensus about not having a logical plan inside of LOProject. I will address
this.

4. I see your point. The existing parser lets you specify an alias on a per column basis,
i.e., 

generate $1 as name, $2 as age, ($2*$3) + 5 as gpa, $2+1  as gpa2

generate $1, $2, ($2*$3) + 5 as gpa, $2+1  as gpa2

For backward compatibility, I will need to support this syntax.

6. Yes, I need to remove them. I posted a patch to unblock the logical to physical translation.
I will get rid of these member variables.

7. Agreed. The logical to physical translation is also looking out for an explicit mention
of flatten. I will fix this too.

> 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, parser_changes.patch, parser_changes_v1.patch, parser_changes_v2.patch,
parser_changes_v3.patch, ParserErrors.txt, visitorWalker.patch
>
>
> Rework the logical plan in line with http://wiki.apache.org/pig/PigExecutionModel

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