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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)