amansinha100 commented on a change in pull request #1620: DRILL-6997: Semijoin is changing the join ordering for some tpcds que… URL: https://github.com/apache/drill/pull/1620#discussion_r251210886
########## File path: exec/java-exec/src/main/java/org/apache/drill/exec/planner/logical/DrillSemiJoinRule.java ########## @@ -0,0 +1,182 @@ +/* + * 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.drill.exec.planner.logical; + +import org.apache.calcite.plan.RelOptCluster; +import org.apache.calcite.plan.RelOptRule; +import org.apache.calcite.plan.RelOptRuleCall; +import org.apache.calcite.plan.RelOptUtil; +import org.apache.calcite.rel.RelNode; +import org.apache.calcite.rel.core.Aggregate; +import org.apache.calcite.rel.core.Join; +import org.apache.calcite.rel.core.JoinInfo; +import org.apache.calcite.rel.core.Project; +import org.apache.calcite.rex.RexBuilder; +import org.apache.calcite.rex.RexNode; +import org.apache.calcite.sql.SqlKind; +import org.apache.calcite.tools.RelBuilder; +import org.apache.calcite.tools.RelBuilderFactory; +import org.apache.calcite.util.ImmutableBitSet; +import org.apache.calcite.util.ImmutableIntList; + +import java.util.ArrayList; +import java.util.List; +import java.util.function.Predicate; + +/** + * Planner rule that creates a {@code DrillSemiJoinRel} from a + * {@link org.apache.calcite.rel.core.Join} on top of a + * {@link org.apache.calcite.rel.logical.LogicalAggregate}. + */ +public abstract class DrillSemiJoinRule extends RelOptRule { + private static final Predicate<Join> IS_LEFT_OR_INNER = + join -> { + switch (join.getJoinType()) { + case LEFT: + case INNER: + return true; + default: + return false; + } + }; + + public static final DrillSemiJoinRule JOIN = + new JoinToSemiJoinRule(Join.class, Aggregate.class, + DrillRelFactories.LOGICAL_BUILDER, "DrillSemiJoinRule:join"); + + protected DrillSemiJoinRule(Class<Join> joinClass, Class<Aggregate> aggregateClass, + RelBuilderFactory relBuilderFactory, String description) { + super(operandJ(joinClass, null, IS_LEFT_OR_INNER, + some(operand(RelNode.class, any()), + operandJ(aggregateClass, null, r -> true, any()))), + relBuilderFactory, description); + } + + protected void perform(RelOptRuleCall call, Project project, + Join join, RelNode left, Aggregate aggregate) { + final RelOptCluster cluster = join.getCluster(); + final RexBuilder rexBuilder = cluster.getRexBuilder(); + if (project != null) { + final ImmutableBitSet bits = + RelOptUtil.InputFinder.bits(project.getProjects(), null); + final ImmutableBitSet rightBits = + ImmutableBitSet.range(left.getRowType().getFieldCount(), + join.getRowType().getFieldCount()); + if (bits.intersects(rightBits)) { + return; + } + } + final JoinInfo joinInfo = join.analyzeCondition(); + if (!joinInfo.rightSet().equals( + ImmutableBitSet.range(aggregate.getGroupCount()))) { + // Rule requires that aggregate key to be the same as the join key. + // By the way, neither a super-set nor a sub-set would work. + return; + } + if (!joinInfo.isEqui()) { + return; + } + final RelBuilder relBuilder = call.builder(); + relBuilder.push(left); + switch (join.getJoinType()) { + case INNER: + final List<Integer> newRightKeyBuilder = new ArrayList<>(); + final List<Integer> aggregateKeys = aggregate.getGroupSet().asList(); + for (int key : joinInfo.rightKeys) { + newRightKeyBuilder.add(aggregateKeys.get(key)); + } + final ImmutableIntList newRightKeys = ImmutableIntList.copyOf(newRightKeyBuilder); + relBuilder.push(aggregate.getInput()); + final RexNode newCondition = + RelOptUtil.createEquiJoinCondition(relBuilder.peek(2, 0), + joinInfo.leftKeys, relBuilder.peek(2, 1), newRightKeys, + rexBuilder); + relBuilder.semiJoin(newCondition); + break; + + case LEFT: + // The right-hand side produces no more than 1 row (because of the + // Aggregate) and no fewer than 1 row (because of LEFT), and therefore + // we can eliminate the semi-join. + break; + + default: + throw new AssertionError(join.getJoinType()); + } + if (project != null) { + relBuilder.project(project.getProjects(), project.getRowType().getFieldNames()); + } + call.transformTo(relBuilder.build()); + } + + /** DrillSemiJoinRule that matches a Join with an Aggregate (without agg functions) as its right + * child. */ Review comment: Pls move ending javadoc marker to next line. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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