jcamachor commented on a change in pull request #1124: URL: https://github.com/apache/hive/pull/1124#discussion_r440929783
########## File path: ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/rules/HiveCardinalityPreservingJoinRule.java ########## @@ -0,0 +1,74 @@ +/* + * 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 org.apache.calcite.plan.RelOptCost; +import org.apache.calcite.plan.RelOptRuleCall; +import org.apache.calcite.plan.RelOptUtil; +import org.apache.calcite.rel.RelNode; +import org.apache.calcite.rel.metadata.JaninoRelMetadataProvider; +import org.apache.calcite.rel.metadata.RelMetadataQuery; +import org.apache.hadoop.hive.ql.optimizer.calcite.HiveDefaultTezModelRelMetadataProvider; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Rule to trigger {@link HiveCardinalityPreservingJoinOptimization} on top of the plan. + */ +public class HiveCardinalityPreservingJoinRule extends HiveFieldTrimmerRule { + private static final Logger LOG = LoggerFactory.getLogger(HiveCardinalityPreservingJoinRule.class); + + private final double factor; + + public HiveCardinalityPreservingJoinRule(double factor) { + super(false, "HiveCardinalityPreservingJoinRule"); + this.factor = Math.max(factor, 0.0); + } + + @Override + protected RelNode trim(RelOptRuleCall call, RelNode node) { + RelNode optimized = new HiveCardinalityPreservingJoinOptimization().trim(call.builder(), node); + if (optimized == node) { + return node; + } + + JaninoRelMetadataProvider original = RelMetadataQuery.THREAD_PROVIDERS.get(); Review comment: Can we move this to the top of the method and put the `RelMetadataQuery.THREAD_PROVIDERS.set(original);` in a finally block? If there is an exception while getting the stats (for instance, if stats are not available), we should make sure that we are setting it back to the original one. ---------------------------------------------------------------- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
