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From "Santhosh Srinivasan (JIRA)" <j...@apache.org>
Subject [jira] Commented: (PIG-158) Rework logical plan
Date Tue, 25 Mar 2008 00:47:25 GMT

    [ https://issues.apache.org/jira/browse/PIG-158?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12581749#action_12581749

Santhosh Srinivasan commented on PIG-158:


1) The way to solve the typing problem is to type your class and not the function. So the
Operator is typed with the type of visitor it uses. So Operator<V extends PlanVisitor>.
LogicalOperator<V extends LOVisitor> extends Operator<LOVisitor>. This makes sure
that you are extending a particular type of the class and solves the problem of having different
visit methods for your entire class hierarchy.

[Santhosh] Thanks for the excellent suggestion to use the type information in the class. I
was able to re-write the classes and reduce the LOVisitor considerably. The code looks better
and more elegant.


5) What I meant to say was for ex. in LOGenerate, if I say generate Count(A) as link_count,
Count(B) as link_quality, will the schema reflect the aliases link_* ? I was not sure because
in many places when you create the new FieldSchema, you use null for the alias.

[Santhosh]  I have addressed in all the operators where I could infer the alias. There are
other places where I could not figure out the alias and left it at null. This might need some
more thinking.

> 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
> Rework the logical plan in line with http://wiki.apache.org/pig/PigExecutionModel

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