[
https://issues.apache.org/jira/browse/BEAM-6114?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16912643#comment-16912643
]
Rui Wang commented on BEAM-6114:
--------------------------------
I am not sure if I understand the thread.
A very basic advantage to separate RelNodes are cost based optimization: each
Rel implementation can compute their cost independently. Merged different
implementation of Join into one Rel apparently make CBO complicated.
> SQL join selection should be done in planner, not in expansion to PTransform
> ----------------------------------------------------------------------------
>
> Key: BEAM-6114
> URL: https://issues.apache.org/jira/browse/BEAM-6114
> Project: Beam
> Issue Type: Improvement
> Components: dsl-sql
> Reporter: Kenneth Knowles
> Assignee: Rahul Patwari
> Priority: Major
> Time Spent: 2h
> Remaining Estimate: 0h
>
> Currently Beam SQL joins all go through a single physical operator which has
> a single PTransform that does all join algorithms based on properties of its
> input PCollections as well as the relational algebra.
> A first step is to make the needed information part of the relational
> algebra, so it can choose a PTransform based on that, and the PTransforms can
> be simpler.
> Second step is to have separate (physical) relational operators for different
> join algorithms.
--
This message was sent by Atlassian Jira
(v8.3.2#803003)
