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https://issues.apache.org/jira/browse/HIVE-5775?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14041085#comment-14041085
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Laljo John Pullokkaran commented on HIVE-5775:
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Cost Model described doesn't apply to current CBO work and for the proposed
branch.
It will apply only for Join Algorithm selection which is not part of the
current work.
IMO moving join reordering to physical optimizer is the not the correct
solution. I would rather leave it in logical, since after doing join reordering
you may able to do other optimizations like, new predicate push down,
transitive inferences….
When we get around to do Join Algorithm selection there will be two cost
formulas one for MR and one for Tez.
I think best solution is to support both cost models and decide which one to
apply based on physical execution layer.
I will update the doc.
> Introduce Cost Based Optimizer to Hive
> --------------------------------------
>
> Key: HIVE-5775
> URL: https://issues.apache.org/jira/browse/HIVE-5775
> Project: Hive
> Issue Type: New Feature
> Reporter: Laljo John Pullokkaran
> Assignee: Laljo John Pullokkaran
> Attachments: CBO-2.pdf, HIVE-5775.1.patch
>
>
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