maropu commented on a change in pull request #28123: [SPARK-31350][SQL] Coalesce bucketed tables for join if applicable URL: https://github.com/apache/spark/pull/28123#discussion_r406568859
########## File path: sql/core/src/main/scala/org/apache/spark/sql/execution/bucketing/InjectBucketHint.scala ########## @@ -0,0 +1,78 @@ +/* + * 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.spark.sql.execution.bucketing + +import org.apache.spark.sql.catalyst.catalog.BucketSpec +import org.apache.spark.sql.catalyst.plans.Inner +import org.apache.spark.sql.catalyst.plans.logical.{Filter, Join, LogicalPlan, Project} +import org.apache.spark.sql.catalyst.rules.Rule +import org.apache.spark.sql.execution.datasources.{HadoopFsRelation, LogicalRelation} + +/** + * This rule injects the bucket related hints and supports the following scenarios: + * - If the two bucketed tables are inner-joined and they differ in the number of buckets, + * the number of buckets for the other table of join is injected as a hint. + */ +object InjectBucketHint extends Rule[LogicalPlan] { + val JOIN_HINT_NUM_BUCKETS: String = "JoinHintNumBuckets" + + private def isPlanEligible(plan: LogicalPlan): Boolean = { + plan.forall { + case _: Filter | _: Project | _: LogicalRelation => true + case _ => false + } + } + + private def getBucketSpec(plan: LogicalPlan): Option[BucketSpec] = { + if (isPlanEligible(plan)) { + plan.collectFirst { + case _ @ LogicalRelation(r: HadoopFsRelation, _, _, _) + if r.bucketSpec.nonEmpty && !r.options.contains(JOIN_HINT_NUM_BUCKETS) => + r.bucketSpec.get + } + } else { + None + } + } + + def apply(plan: LogicalPlan): LogicalPlan = { + plan transform { + case join : Join if join.joinType == Inner => Review comment: nit: format `case join: Join` ---------------------------------------------------------------- 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]
