gengliangwang commented on code in PR #55546: URL: https://github.com/apache/spark/pull/55546#discussion_r3140228653
########## sql/catalyst/src/main/java/org/apache/spark/sql/connector/catalog/SupportsReportCatalogStatistics.java: ########## @@ -0,0 +1,57 @@ +/* + * 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.catalog; + +import org.apache.spark.annotation.Evolving; +import org.apache.spark.sql.connector.read.Statistics; + +/** + * A mix-in interface for {@link Table}. Data sources can implement this interface to report + * table-level statistics to Spark. + * <p> + * The statistics returned here describe the table as a whole, independent of any {@code Scan} + * and independent of any pushed operators (filters, partition pruning, column pruning, + * aggregate pushdown). They are analogous to DSv1's {@code CatalogStatistics} exposed via + * {@code CatalogTable.stats}: a stable, pre-filter, pre-pruning property of the table. + * <p> + * This is distinct from + * {@link org.apache.spark.sql.connector.read.SupportsReportStatistics} on {@code Scan}, which + * reports <em>post-pushdown</em> statistics that reflect the data the scan will actually + * produce. A table may implement both: catalog statistics drive CBO decisions on the + * unfiltered relation (join reordering, broadcast thresholds), while scan statistics tighten + * estimates once pushdown has happened. + * <p> + * Implementations should return statistics without triggering expensive work such as file + * listing or remote metadata fetches beyond what is already cached on the {@code Table} + * instance. Consumers may call this method during optimization, potentially more than once + * per query, and expect a consistent result for a given {@code Table} instance. + * + * @since 4.2.0 + */ +@Evolving +public interface SupportsReportCatalogStatistics extends Table { Review Comment: We need usage of this new trait. E.g. DataSourceV2Relation. Also, there should be test cases for the changes. -- 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]
