vineetgarg02 commented on a change in pull request #671: HIVE-21857 URL: https://github.com/apache/hive/pull/671#discussion_r296055095
########## 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: Review comment: Can you add a comment to explain why OR is sorted differently? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
