danny0405 commented on a change in pull request #1157: [CALCITE-2969] Improve design of join-like relational expressions URL: https://github.com/apache/calcite/pull/1157#discussion_r276497024
########## File path: core/src/main/java/org/apache/calcite/adapter/enumerable/EnumerableNestedLoopJoin.java ########## @@ -0,0 +1,245 @@ +/* + * 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.calcite.adapter.enumerable; + +import org.apache.calcite.linq4j.tree.BlockBuilder; +import org.apache.calcite.linq4j.tree.Expression; +import org.apache.calcite.linq4j.tree.Expressions; +import org.apache.calcite.linq4j.tree.ParameterExpression; +import org.apache.calcite.linq4j.tree.Primitive; +import org.apache.calcite.plan.RelOptCluster; +import org.apache.calcite.plan.RelOptCost; +import org.apache.calcite.plan.RelOptPlanner; +import org.apache.calcite.plan.RelTraitSet; +import org.apache.calcite.rel.RelCollationTraitDef; +import org.apache.calcite.rel.RelNode; +import org.apache.calcite.rel.RelWriter; +import org.apache.calcite.rel.core.CorrelationId; +import org.apache.calcite.rel.core.Join; +import org.apache.calcite.rel.core.JoinRelType; +import org.apache.calcite.rel.metadata.RelMdCollation; +import org.apache.calcite.rel.metadata.RelMetadataQuery; +import org.apache.calcite.rex.RexNode; +import org.apache.calcite.util.BuiltInMethod; +import org.apache.calcite.util.ImmutableBitSet; +import org.apache.calcite.util.Util; + +import com.google.common.collect.ImmutableList; + +import java.lang.reflect.Modifier; +import java.lang.reflect.Type; +import java.util.Set; + +/** Implementation of {@link org.apache.calcite.rel.core.Correlate} in + * {@link org.apache.calcite.adapter.enumerable.EnumerableConvention enumerable calling convention}. */ +public class EnumerableNestedLoopJoin extends Join + implements EnumerableRel { + private final ImmutableBitSet requiredColumns; + + public EnumerableNestedLoopJoin(RelOptCluster cluster, RelTraitSet traits, + RelNode left, RelNode right, RexNode condition, Set<CorrelationId> variablesSet, + ImmutableBitSet requiredColumns, JoinRelType joinType) { + super(cluster, traits, left, right, condition, variablesSet, joinType); + this.requiredColumns = requiredColumns; + } + + /** Creates an EnumerableNestedLoopJoin. */ + public static EnumerableNestedLoopJoin create( + RelNode left, + RelNode right, + RexNode condition, + Set<CorrelationId> variablesSet, + ImmutableBitSet requiredColumns, + JoinRelType joinType) { + assert variablesSet.size() == 0 || variablesSet.size() == 1; + final RelOptCluster cluster = left.getCluster(); + final RelMetadataQuery mq = cluster.getMetadataQuery(); + final RelTraitSet traitSet = + cluster.traitSetOf(EnumerableConvention.INSTANCE) + .replaceIfs(RelCollationTraitDef.INSTANCE, + () -> RelMdCollation.enumerableCorrelate(mq, left, right, joinType)); + return new EnumerableNestedLoopJoin( + cluster, + traitSet, + left, + right, + condition, + variablesSet, + requiredColumns, + joinType); + } + + @Override public RelOptCost computeSelfCost(RelOptPlanner planner, + RelMetadataQuery mq) { + double rowCount = mq.getRowCount(this); + + // Right-hand input is the "build", and hopefully small, input. + final double rightRowCount = right.estimateRowCount(mq); + final double leftRowCount = left.estimateRowCount(mq); + + if (isNonCorrelateSemiJoin()) { + if (Double.isInfinite(leftRowCount)) { + rowCount = leftRowCount; + } else { + rowCount += Util.nLogN(leftRowCount); + } + if (Double.isInfinite(rightRowCount)) { + rowCount = rightRowCount; + } else { + rowCount += rightRowCount; + } + return planner.getCostFactory().makeCost(rowCount, 0, 0).multiplyBy(.01d); + } else { + if (Double.isInfinite(leftRowCount) || Double.isInfinite(rightRowCount)) { + return planner.getCostFactory().makeInfiniteCost(); + } + + Double restartCount = mq.getRowCount(getLeft()); + // RelMetadataQuery.getCumulativeCost(getRight()); does not work for + // RelSubset, so we ask planner to cost-estimate right relation + RelOptCost rightCost = planner.getCost(getRight(), mq); + RelOptCost rescanCost = + rightCost.multiplyBy(Math.max(1.0, restartCount - 1)); + + return planner.getCostFactory().makeCost( + rowCount /* generate results */ + leftRowCount /* scan left results */, + 0, 0).plus(rescanCost); + } + } + + @Override public Join copy(RelTraitSet traitSet, RexNode conditionExpr, RelNode left, + RelNode right, JoinRelType joinType, boolean semiJoinDone) { + return new EnumerableNestedLoopJoin(getCluster(), traitSet, left, right, + conditionExpr, variablesSet, requiredColumns, joinType); + } + + @Override public RelWriter explainTerms(RelWriter pw) { + // This is a normal semi-join. + final RelWriter writer = pw.input("left", left) + .input("right", right); + if (isNonCorrelateSemiJoin()) { + return writer + .item("condition", condition) + .item("joinType", joinType.lowerName) + .itemIf( + "systemFields", + getSystemFieldList(), + !getSystemFieldList().isEmpty()); + } else { + // This is a correlate semi-join. + return writer + .item("correlation", getVariablesSet().iterator().next()) + .item("joinType", joinType.lowerName) + .item("requiredColumns", requiredColumns.toString()); + } + } + + public Result implement(EnumerableRelImplementor implementor, + Prefer pref) { + if (isNonCorrelateSemiJoin()) { + assert joinInfo.isEqui(); + return implementSemiJoin(implementor, pref); + } + return implementCorrelate(implementor, pref); + } + + private Result implementSemiJoin(EnumerableRelImplementor implementor, Review comment: I agree, will make modifications: 1. move `implementSemiJoin` to EnumerableHashJoin 2. rename `BuiltInMethod.JOIN` to `BuiltInMethod.HASH_JOIN`, `BuiltInMethod.SEMI_JOIN` to `BuiltInMethod.HASH_SEMI_JOIN`. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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