xuyangzhong commented on code in PR #26379: URL: https://github.com/apache/flink/pull/26379#discussion_r2052274380
########## flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/plan/reuse/SinkReuser.java: ########## @@ -0,0 +1,211 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.flink.table.planner.plan.reuse; + +import org.apache.flink.table.planner.plan.abilities.sink.SinkAbilitySpec; +import org.apache.flink.table.planner.plan.nodes.calcite.Sink; +import org.apache.flink.table.planner.plan.nodes.physical.batch.BatchPhysicalSink; +import org.apache.flink.table.planner.plan.nodes.physical.batch.BatchPhysicalUnion; +import org.apache.flink.table.planner.plan.utils.RelExplainUtil; +import org.apache.flink.util.Preconditions; + +import org.apache.calcite.plan.RelTraitSet; +import org.apache.calcite.rel.RelNode; +import org.apache.calcite.rel.core.Union; + +import java.util.ArrayList; +import java.util.Arrays; +import java.util.Collections; +import java.util.IdentityHashMap; +import java.util.List; +import java.util.Optional; +import java.util.Set; +import java.util.stream.Collectors; + +/** + * This checks if we can find duplicate sinks that can be reused. If so, only one of these sinks + * will be used. This is an optimization so that we do not need to process multiple sinks that are + * actually representing the same destination table. + * + * <p>This optimization is only used in the STATEMENT SET clause with multiple INSERT INTO. + * + * <p>Examples in SQL look like: + * + * <pre>{@code + * BEGIN STATEMENT SET; + * INSERT INTO sink1 SELECT * FROM source1; + * INSERT INTO sink1 SELECT * FROM source2; + * INSERT INTO sink2 SELECT * FROM source3; + * END; + * }</pre> + * + * <p>The plan is as follows: + * + * <pre>{@code + * TableScan1 —— Sink1 + * TableScan2 —— Sink1 + * TableScan3 —— Sink2 + * }</pre> + * + * <p>After reused, the plan will be changed as follows: + * + * <pre>{@code + * TableScan1 --\ + * Union -- Sink1 + * TableScan2 --/ + * + * TableScan3 —— Sink3 + * }</pre> + */ +public class SinkReuser { + + public List<RelNode> reuseDuplicatedSink(List<RelNode> relNodes) { + // Find all sinks + List<Sink> allSinkNodes = + relNodes.stream() + .filter(node -> node instanceof Sink) + .map(node -> (Sink) node) + .collect(Collectors.toList()); + List<ReusableSinkGroup> reusableSinkGroups = groupReusableSink(allSinkNodes); + + Set<Sink> reusedSinkNodes = reuseSinkAndAddUnion(reusableSinkGroups); + + // Remove all unused sink nodes + return relNodes.stream() + .filter(root -> !(root instanceof Sink) || reusedSinkNodes.contains(root)) + .collect(Collectors.toList()); + } + + private Set<Sink> reuseSinkAndAddUnion(List<ReusableSinkGroup> reusableSinkGroups) { + final Set<Sink> reusedSinkNodes = Collections.newSetFromMap(new IdentityHashMap<>()); + reusableSinkGroups.forEach( + group -> { + List<Sink> originalSinks = group.originalSinks; + if (originalSinks.size() <= 1) { + Preconditions.checkState(originalSinks.size() == 1); + reusedSinkNodes.add(originalSinks.get(0)); + return; + } + List<RelNode> allSinkInputs = new ArrayList<>(); + for (Sink sinkNode : originalSinks) { + allSinkInputs.add(sinkNode.getInput()); + } + + // Use the first sink node as the final reused sink node + Sink reusedSink = originalSinks.get(0); + + Union unionForReusedSinks; + + unionForReusedSinks = + new BatchPhysicalUnion( + reusedSink.getCluster(), + group.inputTraitSet, + allSinkInputs, + true, + // use sink input row type + reusedSink.getRowType()); + + reusedSink.replaceInput(0, unionForReusedSinks); + reusedSinkNodes.add(reusedSink); + }); + return reusedSinkNodes; + } + + /** + * Grouping sinks that can be reused with each other. + * + * @param allSinkNodes in the plan. + * @return a list contains all grouped sink. + */ + private List<ReusableSinkGroup> groupReusableSink(List<Sink> allSinkNodes) { + List<ReusableSinkGroup> reusableSinkGroups = new ArrayList<>(); + + for (Sink currentSinkNode : allSinkNodes) { + Optional<ReusableSinkGroup> targetGroup = + reusableSinkGroups.stream() + .filter( + reusableSinkGroup -> + reusableSinkGroup.canBeReused(currentSinkNode)) + .findFirst(); + + if (targetGroup.isPresent()) { + targetGroup.get().originalSinks.add(currentSinkNode); + } else { + // If the current sink cannot be reused with any existing groups, create a new + // group. + reusableSinkGroups.add(new ReusableSinkGroup(currentSinkNode)); + } + } + return reusableSinkGroups; + } + + public String getDigest(Sink sink) { Review Comment: Currently we haven't removed the logic of ignoring targetColumns, right? I mainly consider it for the maintenance of the code in the future. If BatchPhysicalSink#getRelDetailedDescription is clearly not enough, I'm ok to introduce this new method to full it. But just for now, it seems to be enough. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
