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Posted to issues@flink.apache.org by "xingyuan cheng (Jira)" <ji...@apache.org> on 2023/02/23 02:13:00 UTC
[jira] [Comment Edited] (FLINK-27815) Improve the join reorder strategy for batch sql job
[ https://issues.apache.org/jira/browse/FLINK-27815?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17692447#comment-17692447 ]
xingyuan cheng edited comment on FLINK-27815 at 2/23/23 2:12 AM:
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Hello [~godfreyhe] , I have two questions about question 1
1. Do we need to implement the heuristicJoinOrder similar to Calcite to solve the order problem of multi-table joins
2. The JoinAssociationRule and JoinPushThroughJoinRule of Calcite will match the left deep tree and take effect on the inner join. Do we also need support?
was (Author: complone):
Hello [~godfreyhe] , I have two questions about question 1
1. Do we need to implement the heuristicJoinOrder similar to Calcite to solve the order problem of multi-table joins
2. The JoinAssociationRule of Calcite will match the left deep tree and take effect on the inner join. Do we also need support?
> Improve the join reorder strategy for batch sql job
> ----------------------------------------------------
>
> Key: FLINK-27815
> URL: https://issues.apache.org/jira/browse/FLINK-27815
> Project: Flink
> Issue Type: New Feature
> Components: Table SQL / Planner
> Reporter: godfrey he
> Assignee: godfrey he
> Priority: Major
> Labels: pull-request-available
>
> Join is heavy operation in the execution, the join order in a query can have a significant impact on the query’s performance.
> Currently, the planner has one join reorder strategy which is provided by Apache Calcite, and it strongly depends on the statistics.
> It's better we can provide different join reorder strategies for different situations, such as:
> 1. provide a join reorder strategy without statistics, e.g. eliminate cross joins
> 2. improve current join reorders strategy with statistics
> 3. provide hints to allow users to choose join order strategy
> 4. ...
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