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https://issues.apache.org/jira/browse/PIG-3634?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Daniel Dai updated PIG-3634:
----------------------------
Attachment: PIG-3634-0.patch
Attach partial patch. Operators_4 is still failing, I will attach a new patch
once fixed.
> Improve performance of order-by
> -------------------------------
>
> Key: PIG-3634
> URL: https://issues.apache.org/jira/browse/PIG-3634
> Project: Pig
> Issue Type: Sub-task
> Components: tez
> Reporter: Daniel Dai
> Assignee: Daniel Dai
> Fix For: tez-branch
>
> Attachments: PIG-3634-0.patch
>
>
> This is a followup for PIG-3534. In PIG-3534, we use 5 vertexes (3 DAGs) to
> implement an order-by. We can optimize to use 4 vertexes in 1 DAG:
> vertex 1: close the current vertex, create input + samples input
> vertex 2: aggregate samples to create quantiles
> vertex 3: use quantiles to partition input
> vertex 4: sort input after partition
> The DAG is:
> {code}
> vertex 1 ------------------> vertex 3 ------> vertex 4
> \--> vertex 2 ---/
> {code}
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