Zhu Zhu created FLINK-25995: ------------------------------- Summary: Make implicit assumption of SQL local keyBy/groupBy explicit Key: FLINK-25995 URL: https://issues.apache.org/jira/browse/FLINK-25995 Project: Flink Issue Type: Sub-task Components: Table SQL / Planner Affects Versions: 1.15.0 Reporter: Zhu Zhu Fix For: 1.15.0
If there are multiple consecutive the same groupBy(i.e. keyBy), SQL planner will change them except the first one to use forward partitioner, so that these operators can be chained to reduce unnecessary shuffles. However, sometimes the local keyBy operators are not chained (e.g. multiple inputs), and this kind of forward partitioners will turn into forward job edges. These forward edges still have the local keyBy assumption, so that they cannot be changed into rescale/rebalance edges, otherwise it can lead to incorrect results. This prevents the adaptive batch scheduler from determining parallelism for other forward edge downstream job vertices (see FLINK-25046). To solve it, I propose to introduce a new {{ForwardForRescalePartitioner}}. When SQL planner optimizes the case of multiple consecutive the same groupBy, it should use the proposed partitioner, so that the runtime framework can further decide whether the partitioner can be changed to rescale or not. -- This message was sent by Atlassian Jira (v8.20.1#820001)