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https://issues.apache.org/jira/browse/PIG-1747?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12965496#action_12965496
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Thejas M Nair commented on PIG-1747:
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bq. Can you brief the difference of physical pattern match vs logical patten
match?
Pattern match for logical plan is done by
org.apache.pig.newplan.optimizer.Rule, which operates on plans that use newplan
base classes. Physical plan has not been migrated to these base classes, so it
can't use the Rule class for pattern matching. This was the reason to create a
separate pattern match class. Otherwise the basic requirements are same in both
cases.
The physical pattern match class also makes it easier to get to the matched
nodes without needing code for navigating the matched tree.
> pattern match classes for matching patterns in physical plan
> -------------------------------------------------------------
>
> Key: PIG-1747
> URL: https://issues.apache.org/jira/browse/PIG-1747
> Project: Pig
> Issue Type: Improvement
> Reporter: Thejas M Nair
> Assignee: Thejas M Nair
> Fix For: 0.9.0
>
> Attachments: PIG-1747.1.patch
>
>
> Map-reduce plan optimization phase of query planning in pig uses several
> visitors. Each of these visitors use custom code to identify patterns in
> physical plan to determine if the optimization should be applied. Having
> pattern match utility classes that works with physical plan will make writing
> new visitors easier.
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