vineetgarg02 commented on a change in pull request #671: HIVE-21857 URL: https://github.com/apache/hive/pull/671#discussion_r296056369
########## File path: ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/rules/HiveFilterSortPredicates.java ########## @@ -0,0 +1,268 @@ +/* + * 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.hadoop.hive.ql.optimizer.calcite.rules; + +import java.util.Comparator; +import java.util.List; +import java.util.stream.Collectors; +import org.apache.calcite.plan.RelOptRule; +import org.apache.calcite.plan.RelOptRuleCall; +import org.apache.calcite.rel.RelNode; +import org.apache.calcite.rel.core.Filter; +import org.apache.calcite.rel.metadata.RelMetadataQuery; +import org.apache.calcite.rex.RexCall; +import org.apache.calcite.rex.RexDynamicParam; +import org.apache.calcite.rex.RexFieldAccess; +import org.apache.calcite.rex.RexInputRef; +import org.apache.calcite.rex.RexLiteral; +import org.apache.calcite.rex.RexNode; +import org.apache.calcite.rex.RexShuttle; +import org.apache.calcite.rex.RexVisitorImpl; +import org.apache.calcite.util.Pair; +import org.apache.hadoop.hive.ql.optimizer.calcite.stats.FilterSelectivityEstimator; +import org.apache.hadoop.hive.ql.optimizer.calcite.stats.HiveRelMdSize; + + +/** + * Rule that sorts conditions in a filter predicate to accelerate query processing + * based on selectivity and compute cost. Currently it is not applied recursively, + * i.e., it is only applied to top predicates in the condition. + */ +public class HiveFilterSortPredicates extends RelOptRule { + + public static final HiveFilterSortPredicates INSTANCE = new HiveFilterSortPredicates(); + + + private HiveFilterSortPredicates() { + super( + operand(Filter.class, + operand(RelNode.class, any()))); + } + + @Override + public boolean matches(RelOptRuleCall call) { + final Filter filter = call.rel(0); + + HiveRulesRegistry registry = call.getPlanner().getContext().unwrap(HiveRulesRegistry.class); + + // If this operator has been visited already by the rule, + // we do not need to apply the optimization + if (registry != null && registry.getVisited(this).contains(filter)) { + return false; + } + + return true; + } + + @Override + public void onMatch(RelOptRuleCall call) { + final Filter filter = call.rel(0); + final RelNode input = call.rel(1); + + // Register that we have visited this operator in this rule + HiveRulesRegistry registry = call.getPlanner().getContext().unwrap(HiveRulesRegistry.class); + if (registry != null) { + registry.registerVisited(this, filter); + } + + final RexNode originalCond = filter.getCondition(); + RexSortPredicatesShuttle sortPredicatesShuttle = new RexSortPredicatesShuttle( + input, filter.getCluster().getMetadataQuery()); + final RexNode newCond = originalCond.accept(sortPredicatesShuttle); + if (!sortPredicatesShuttle.modified) { + // We are done, bail out + return; + } + + // We register the new filter so we do not fire the rule on it again + final Filter newFilter = filter.copy(filter.getTraitSet(), input, newCond); + if (registry != null) { + registry.registerVisited(this, newFilter); + } + + call.transformTo(newFilter); + } + + /** + * If the expression is an AND/OR, it will sort predicates accordingly + * to maximize performance. + * In particular, for AND clause: + * rank = (selectivity - 1) / cost per tuple + * Similarly, for OR clause: + * rank = (-selectivity) / cost per tuple + */ + private static class RexSortPredicatesShuttle extends RexShuttle { + + private FilterSelectivityEstimator selectivityEstimator; + private boolean modified; + + private RexSortPredicatesShuttle(RelNode inputRel, RelMetadataQuery mq) { + selectivityEstimator = new FilterSelectivityEstimator(inputRel, mq); + modified = false; + } + + @Override + public RexNode visitCall(final RexCall call) { + switch (call.getKind()) { + case AND: + List<RexNode> newAndOperands = call.getOperands() + .stream() + .map(pred -> new Pair<>(pred, rankingAnd(pred))) + .sorted(Comparator.comparing(Pair::getValue, Comparator.nullsLast(Double::compare))) + .map(Pair::getKey) + .collect(Collectors.toList()); + if (!call.getOperands().equals(newAndOperands)) { + modified = true; + return call.clone(call.getType(), newAndOperands); + } + break; + case OR: + List<RexNode> newOrOperands = call.getOperands() + .stream() + .map(pred -> new Pair<>(pred, rankingOr(pred))) + .sorted(Comparator.comparing(Pair::getValue, Comparator.nullsLast(Double::compare))) + .map(Pair::getKey) + .collect(Collectors.toList()); + if (!call.getOperands().equals(newOrOperands)) { + modified = true; + return call.clone(call.getType(), newOrOperands); + } + break; + } + return call; + } + + private Double rankingAnd(RexNode e) { + Double selectivity = selectivityEstimator.estimateSelectivity(e); + if (selectivity == null) { + return null; + } + Double costPerTuple = costPerTuple(e); + if (costPerTuple == null) { + return null; + } + return (selectivity - 1d) / costPerTuple; + } + + private Double rankingOr(RexNode e) { + Double selectivity = selectivityEstimator.estimateSelectivity(e); + if (selectivity == null) { + return null; + } + Double costPerTuple = costPerTuple(e); + if (costPerTuple == null) { + return null; + } + return -selectivity / costPerTuple; + } + + private Double costPerTuple(RexNode e) { + return e.accept(new RexFunctionCost()); + } + + } + + /** + * The cost of a call expression e is computed as: + * cost(e) = functionCost + sum_1..n(byteSize(o_i) + cost(o_i)) + * with the call having operands i in 1..n. + */ + private static class RexFunctionCost extends RexVisitorImpl<Double> { + + private RexFunctionCost() { + super(true); + } + + @Override + public Double visitCall(RexCall call) { + if (!deep) { + return null; + } + + Double cost = 0.d; + for (RexNode operand : call.operands) { + Double operandCost = operand.accept(this); + if (operandCost == null) { + return null; + } + cost += operandCost; + Double size = HiveRelMdSize.averageTypeSize(operand.getType()); + if (size == null) { + return null; + } + cost += size; + } + + return cost + functionCost(call); + } + + private static Double functionCost(RexCall call) { + switch (call.getKind()) { + case EQUALS: + case NOT_EQUALS: + case LESS_THAN: + case GREATER_THAN: + case LESS_THAN_OR_EQUAL: + case GREATER_THAN_OR_EQUAL: + case IS_NOT_NULL: + case IS_NULL: + case IS_TRUE: + case IS_NOT_TRUE: + case IS_FALSE: + case IS_NOT_FALSE: + return 1d; + + case BETWEEN: + return 3d; + + case IN: + return 2d * (call.getOperands().size() - 1); Review comment: Can you add comment to explain what is the rationale for choosing these "arbitrary constant" for function costs. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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