walterddr commented on a change in pull request #8468: [FLINK-12399][table] Adding PushDownTableSource interface to fix FilterableTableSource applyPredicate problem URL: https://github.com/apache/flink/pull/8468#discussion_r317340483
########## File path: flink-table/flink-table-common/src/main/java/org/apache/flink/table/sources/PushDownTableSource.java ########## @@ -0,0 +1,36 @@ +/* + * 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.sources; + +/** + * Base interface for supporting operator push-down to a {@code TableSource}. + * A {@code TableSource} extending this interface will be able to acquire additional + * information regarding the push-down information of the table source. + * + * @param <T> The return type of the {@link TableSource}. + */ +public interface PushDownTableSource<T> { + + /** + * Describes the push down rule for this specific table source. + * + * @return A String explaining the {@link PushDownTableSource}. + */ + String explainPushDown(); Review comment: I figure I might be able to use some sort of default here but it will be hard without understanding what exactly is the pushdown is. open to any suggestion. However I think having this API here alone prevents user from not overriding the `pushdown` and prevents the problematic pushdown rule application ---------------------------------------------------------------- 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
