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_r250847230
########## 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 DrillSemiJoinRule} 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. */ + public static class JoinToSemiJoinRule extends DrillSemiJoinRule { + + /** Creates a JoinToSemiJoinRule. */ + public JoinToSemiJoinRule( + Class<Join> joinClass, Class<Aggregate> aggregateClass, + RelBuilderFactory relBuilderFactory, String description) { + super(joinClass, aggregateClass, relBuilderFactory, description); + } + } + + /** + * Check for the row schema if they aggregate's output rowtype is different + * from its input rowtype then do not convert the join to a semi join. + */ + private static boolean isRowTypeSame(RelNode join, RelNode left, RelNode rightInput) { + return join.getRowType().getFieldCount() == left.getRowType().getFieldCount() + Review comment: I am wondering if this should check for field count == 1 or leave it general ? If we leave it general, then should make sure to test correctness. My preference is to restrict it. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
