dang-stripe commented on code in PR #18158: URL: https://github.com/apache/pinot/pull/18158#discussion_r3062036182
########## pinot-query-planner/src/main/java/org/apache/pinot/query/planner/physical/v2/opt/rules/LookupJoinRule.java: ########## @@ -0,0 +1,189 @@ +/** + * 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.pinot.query.planner.physical.v2.opt.rules; + +import java.util.ArrayList; +import java.util.List; +import javax.annotation.Nullable; +import org.apache.calcite.rel.RelDistribution; +import org.apache.calcite.rel.core.Join; +import org.apache.pinot.calcite.rel.hint.PinotHintOptions; +import org.apache.pinot.calcite.rel.traits.PinotExecStrategyTrait; +import org.apache.pinot.query.context.PhysicalPlannerContext; +import org.apache.pinot.query.planner.physical.v2.ExchangeStrategy; +import org.apache.pinot.query.planner.physical.v2.PRelNode; +import org.apache.pinot.query.planner.physical.v2.PinotDataDistribution; +import org.apache.pinot.query.planner.physical.v2.nodes.PhysicalExchange; +import org.apache.pinot.query.planner.physical.v2.opt.PRelNodeTransformer; + + +/** + * Post-pass rule that isolates every lookup join in its own plan fragment. + * + * <p>Runs after {@link WorkerExchangeAssignmentRule}, which assigns workers and exchanges generically (with zero + * lookup join awareness). This rule then post-processes lookup joins to ensure:</p> + * <ol> + * <li><b>Right side</b>: Exchange converted to {@link ExchangeStrategy#LOOKUP_LOCAL_EXCHANGE} — a pseudo-exchange + * that does not split fragments. Later, during plan fragment assignment, + * {@code PlanFragmentAndMailboxAssignment.processLookupLocalExchange} registers the dim table with fake + * segments so the fragment is classified as a leaf stage for {@code DimensionTableDataManager} access.</li> + * <li><b>Left side</b>: Exchange exists (inserts {@link ExchangeStrategy#IDENTITY_EXCHANGE} if missing, e.g. when + * the left input is an intermediate node like a hash join with the same workers).</li> + * <li><b>Above</b>: Lookup join wrapped in {@link ExchangeStrategy#IDENTITY_EXCHANGE} so downstream nodes + * (other joins, sorts) are not absorbed into the lookup join's leaf fragment.</li> + * </ol> + * + * <p>This achieves the same outcome as V1, where {@code WorkerManager.assignWorkersToNonRootFragment} detects + * lookup joins and assigns the same workers as the fact table while registering fake empty segments for the + * dim table.</p> + */ +public class LookupJoinRule implements PRelNodeTransformer { + private final PhysicalPlannerContext _context; + + public LookupJoinRule(PhysicalPlannerContext context) { + _context = context; + } + + @Override + public PRelNode execute(PRelNode rootNode) { + // TODO: Support lookup joins in Lite mode. Currently fails with "Right input must be leaf + // operator" because the broker lacks DimensionTableDataManager. + if (_context.isUseLiteMode()) { + return rootNode; + } + return transform(rootNode, null); + } Review Comment: i've skipped lite mode since it adds quite a bit of scope. the broker gets assigned as worker for the join fragment so we'd need reassign it to a server and handle routing. -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
