wuchong commented on a change in pull request #8695: [FLINK-12805][FLINK-12808][FLINK-12809][table-api] Introduce PartitionableTableSource and PartitionableTableSink and OverwritableTableSink URL: https://github.com/apache/flink/pull/8695#discussion_r296072983
########## File path: flink-table/flink-table-common/src/main/java/org/apache/flink/table/sinks/PartitionableTableSink.java ########## @@ -0,0 +1,67 @@ +/* + * 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.flink.table.sinks; + +import org.apache.flink.annotation.Experimental; + +import java.util.List; + +/** + * An interface for partitionable {@link TableSink TableSinks}. A partitionable sink can writes + * query results to partitions. + * + * <p>Partition columns are defined via {@link #getPartitionFieldNames()} and the field names + * should be sorted in a strict order. And all the partition fields should exist in the + * {@link TableSink#getTableSchema()}. + * + * <p>For example, a partitioned table named {@code my_table} with a table schema + * {@code [a INT, b VARCHAR, c DOUBLE, dt VARCHAR, country VARCHAR]} is partitioned on columns + * {@code ds, country}. Then {@code ds} is the first partition column, and + * {@code country} is the secondary partition column. + */ +@Experimental +public interface PartitionableTableSink { + + /** + * Gets the partition field names of the table. The partition field names should be sorted in + * a strict order, i.e. they have the order as specified in the PARTITION statement in DDL. + * This should be an empty set if the table is not partitioned. + * + * <p>All the partition fields should exist in the {@link TableSink#getTableSchema()}. + * + * @return partition field names of the table, empty if the table is not partitioned. + */ + List<String> getPartitionFieldNames(); + + /** + * If returns true, sink can trust all records will definitely be sorted by partition fields + * before consumed by the {@link TableSink}, i.e. the sink will receive data one partition + * at a time. For some sinks, this can be used to reduce the partition writers to improve Review comment: reduce number of writers ---------------------------------------------------------------- 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: us...@infra.apache.org With regards, Apache Git Services
