dongjoon-hyun commented on code in PR #38904: URL: https://github.com/apache/spark/pull/38904#discussion_r1042043454
########## sql/catalyst/src/main/java/org/apache/spark/sql/connector/read/colstats/ColumnStatistics.java: ########## @@ -0,0 +1,84 @@ +/* + * 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.colstats; + +import java.math.BigInteger; +import java.util.Optional; +import java.util.OptionalLong; + +import org.apache.spark.annotation.Evolving; +import org.apache.spark.sql.connector.read.Statistics; + +/** + * An interface to represent column statistics, which is part of + * {@link Statistics}. + * + * @since 3.4.0 + */ +@Evolving +public interface ColumnStatistics { + + /** + * @return number of distinct values in the column + */ + default Optional<BigInteger> distinctCount() { + return Optional.empty(); + } + + /** + * @return minimum value in the column + */ + default Optional<Object> min() { + return Optional.empty(); + } + + /** + * @return maximum value in the column + */ + default Optional<Object> max() { + return Optional.empty(); + } + + /** + * @return number of nulls in the column + */ + default Optional<BigInteger> nullCount() { + return Optional.empty(); + } + + /** + * @return average length of the values in the column + */ + default OptionalLong avgLen() { + return OptionalLong.empty(); + } + + /** + * @return maximum length of the values in the column + */ + default OptionalLong maxLen() { + return OptionalLong.empty(); + } + + /** + * @return histogram of the values in the column + */ + default Optional<Histogram> histogram() { Review Comment: I agree with you that this could be unused APIs due to many practical reasons in many DSv2 implementations, but the interface itself is useful with a concrete purpose. -- 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]
