dilipbiswal commented on a change in pull request #23750: [SPARK-19712][SQL] Pushing Left Semi and Left Anti joins through Project, Aggregate, Window, Union etc. URL: https://github.com/apache/spark/pull/23750#discussion_r258250376
########## File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/PushDownLeftSemiAntiJoin.scala ########## @@ -0,0 +1,188 @@ +/* + * 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.catalyst.optimizer + +import org.apache.spark.sql.catalyst.expressions._ +import org.apache.spark.sql.catalyst.plans._ +import org.apache.spark.sql.catalyst.plans.logical._ +import org.apache.spark.sql.catalyst.rules.Rule + +/** + * Pushes Left semi and Left Anti joins below the following operators. + * 1) Project + * 2) Window + * 3) Union + * 4) Aggregate + * 5) Other permissible unary operators. please see [[PushDownPredicate.canPushThrough]]. + */ +object PushDownLeftSemiAntiJoin extends Rule[LogicalPlan] with PredicateHelper { + def apply(plan: LogicalPlan): LogicalPlan = plan transform { + // LeftSemi/LeftAnti over Project + case Join(p @ Project(pList, gChild), rightOp, LeftSemiOrAnti(joinType), joinCond, hint) + if pList.forall(_.deterministic) && + !pList.exists(ScalarSubquery.hasScalarSubquery)&& Review comment: @cloud-fan We would keep this after the refactoring. Currently , except is planned using anti join. Here is the test that exhibits the problem. ``` sql SELECT (SELECT min(k) FROM t2 WHERE t2.k = t1.k) min_t2 FROM t1 MINUS SELECT (SELECT min(k) FROM t2) abs_min_t2 FROM t1 WHERE t1.k = 'one' ``` After the except operator is replaced .. the plan is : ``` GlobalLimit 21 +- LocalLimit 21 +- Project [cast(min_t2#245 as string) AS min_t2#254] +- Distinct +- Join LeftAnti, (min_t2#245 <=> abs_min_t2#247) :- Project [scalar-subquery#244 [(k#242 = k#240)] AS min_t2#245] : : +- Aggregate [k#242], [min(k#242) AS min(k)#249, k#242] : : +- Project [k#242] : : +- LocalRelation [k#242, v#243] : +- Project [k#240, v#241] : +- LocalRelation [k#240, v#241] +- Project [scalar-subquery#246 [] AS abs_min_t2#247] : +- Aggregate [min(k#242) AS min(k)#251] : +- Project [k#242] : +- LocalRelation [k#242, v#243] +- Filter (k#240 = one) +- Project [k#240, v#241] +- LocalRelation [k#240, v#241] ``` Here we are not pushing down the leftanti operator below project. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on 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]
