hadoop-pig-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Ying He (JIRA)" <j...@apache.org>
Subject [jira] Commented: (PIG-1178) LogicalPlan and Optimizer are too complex and hard to work with
Date Thu, 14 Jan 2010 20:47:54 GMT

    [ https://issues.apache.org/jira/browse/PIG-1178?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12800353#action_12800353
] 

Ying He commented on PIG-1178:
------------------------------

to answer Daniel's questions:

. In Rule.match, is PatternMatchOperatorPlan only contains leave nodes but not edge information?
If so, instead of saying "A list of all matched sub-plans", can we put more details in the
comments?

The returned lists are plans. You can call getPredecessors() or getSuccessors() on any node
in the plan. The implementation doesn't keep edge information, it calls the base plan for
this information and return the operators that are in this sub-plan. So looking from outside,
it is a plan, it's just read-only, and method to update the plan would throw an exception.

> LogicalPlan and Optimizer are too complex and hard to work with
> ---------------------------------------------------------------
>
>                 Key: PIG-1178
>                 URL: https://issues.apache.org/jira/browse/PIG-1178
>             Project: Pig
>          Issue Type: Improvement
>            Reporter: Alan Gates
>            Assignee: Ying He
>         Attachments: expressions-2.patch, expressions.patch, lp.patch, PIG_1178.patch
>
>
> The current implementation of the logical plan and the logical optimizer in Pig has proven
to not be easily extensible. Developer feedback has indicated that adding new rules to the
optimizer is quite burdensome. In addition, the logical plan has been an area of numerous
bugs, many of which have been difficult to fix. Developers also feel that the logical plan
is difficult to understand and maintain. The root cause for these issues is that a number
of design decisions that were made as part of the 0.2 rewrite of the front end have now proven
to be sub-optimal. The heart of this proposal is to revisit a number of those proposals and
rebuild the logical plan with a simpler design that will make it much easier to maintain the
logical plan as well as extend the logical optimizer. 
> See http://wiki.apache.org/pig/PigLogicalPlanOptimizerRewrite for full details.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message