thomasrebele commented on a change in pull request #2109: URL: https://github.com/apache/calcite/pull/2109#discussion_r472132673
########## File path: core/src/main/java/org/apache/calcite/adapter/enumerable/EnumerableLimitSort.java ########## @@ -0,0 +1,146 @@ +/* + * 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.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.RelCollation; +import org.apache.calcite.rel.RelNode; +import org.apache.calcite.rel.core.Sort; +import org.apache.calcite.rel.metadata.RelMetadataQuery; +import org.apache.calcite.rex.RexLiteral; +import org.apache.calcite.rex.RexNode; +import org.apache.calcite.util.BuiltInMethod; +import org.apache.calcite.util.Pair; + +import static org.apache.calcite.adapter.enumerable.EnumerableLimit.getExpression; + +/** + * Implementation of {@link org.apache.calcite.rel.core.Sort} in + * {@link org.apache.calcite.adapter.enumerable.EnumerableConvention enumerable calling convention}. + * It optimizes sorts that have a limit and an optional offset. + */ +public class EnumerableLimitSort extends Sort implements EnumerableRel { + + /** + * Creates an EnumerableLimitSort. + * + * <p>Use {@link #create} unless you know what you're doing. + */ + public EnumerableLimitSort( + RelOptCluster cluster, + RelTraitSet traitSet, + RelNode input, + RelCollation collation, + RexNode offset, + RexNode fetch) { + super(cluster, traitSet, input, collation, offset, fetch); + assert this.getConvention() instanceof EnumerableConvention; + assert this.getConvention() == input.getConvention(); + } + + /** Creates an EnumerableLimitSort. */ + public static EnumerableLimitSort create( + RelNode input, + RelCollation collation, + RexNode offset, + RexNode fetch) { + final RelOptCluster cluster = input.getCluster(); + final RelTraitSet traitSet = cluster.traitSetOf(EnumerableConvention.INSTANCE).replace( + collation); + return new EnumerableLimitSort(cluster, traitSet, input, collation, offset, fetch); + } + + @Override public EnumerableLimitSort copy( + RelTraitSet traitSet, + RelNode newInput, + RelCollation newCollation, + RexNode offset, + RexNode fetch) { + return new EnumerableLimitSort( + this.getCluster(), + traitSet, + newInput, + newCollation, + offset, + fetch); + } + + @Override public Result implement(EnumerableRelImplementor implementor, Prefer pref) { + final BlockBuilder builder = new BlockBuilder(); + final EnumerableRel child = (EnumerableRel) this.getInput(); + final Result result = implementor.visitChild(this, 0, child, pref); + final PhysType physType = PhysTypeImpl.of( + implementor.getTypeFactory(), + this.getRowType(), + result.format); + Expression childExp = builder.append("child", result.block); + + PhysType inputPhysType = result.physType; + final Pair<Expression, Expression> pair = + inputPhysType.generateCollationKey(this.collation.getFieldCollations()); + + Expression fetchVal; + if (this.fetch == null) { + fetchVal = Expressions.constant(Integer.valueOf(Integer.MAX_VALUE)); + } else { + fetchVal = getExpression(this.fetch); + } + + Expression offsetVal = this.offset == null ? Expressions.constant(Integer.valueOf(0)) + : getExpression(this.offset); + + builder.add( + Expressions.return_( + null, Expressions.call( + BuiltInMethod.ORDER_BY_WITH_FETCH_AND_OFFSET.method, Expressions.list( + childExp, + builder.append("keySelector", pair.left)) + .appendIfNotNull(builder.appendIfNotNull("comparator", pair.right)) + .appendIfNotNull( + builder.appendIfNotNull("offset", + Expressions.constant(offsetVal))) + .appendIfNotNull( + builder.appendIfNotNull("fetch", + Expressions.constant(fetchVal))) + ))); + return implementor.result(physType, builder.toBlock()); + } + + @Override public RelOptCost computeSelfCost(RelOptPlanner planner, RelMetadataQuery mq) { + final double rowCount = mq.getRowCount(this.input).doubleValue(); + double toSort = this.fetch == null ? rowCount : RexLiteral.intValue(this.fetch); Review comment: I've modified the cost, so that it falls back to the row count if there are dynamic parameters ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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