EnricoMi commented on code in PR #35965: URL: https://github.com/apache/spark/pull/35965#discussion_r862668354
########## sql/catalyst/src/main/java/org/apache/spark/sql/connector/read/SupportsReportOrdering.java: ########## @@ -0,0 +1,40 @@ +/* + * 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.connector.read; + +import org.apache.spark.annotation.Evolving; +import org.apache.spark.sql.connector.expressions.SortOrder; + +/** + * A mix in interface for {@link Scan}. Data sources can implement this interface to + * report the order of data in each partition to Spark. + * Global order is part of the partitioning, see {@link SupportsReportPartitioning}. + * <p> + * Spark uses ordering information to exploit existing order to avoid sorting required by + * subsequent operations. + * + * @since 3.4.0 + */ +@Evolving +public interface SupportsReportOrdering extends Scan { + + /** + * Returns the order in each partition of this data source scan. + */ + SortOrder[] outputOrdering(); Review Comment: An empty array return value would mean the same as setting `SparkPlan.outputOrdering` to that empty array or `Nil`, which is the default. That interface does not document the semantics of it, but as this is the default, it probably means "no order". From the API, it does not look like Spark can distinguish between "not knowing the order" and "there is no order". -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
