JingsongLi commented on a change in pull request #8102: [FLINK-12087][table-runtime-blink] Introduce over window operators to blink batch URL: https://github.com/apache/flink/pull/8102#discussion_r272033041
########## File path: flink-table/flink-table-runtime-blink/src/main/java/org/apache/flink/table/generated/BoundComparator.java ########## @@ -0,0 +1,49 @@ +/* + * 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.generated; + +import org.apache.flink.table.dataformat.BaseRow; + +import java.io.Serializable; + +/** + * comparing boundary values. + */ +public interface BoundComparator extends Serializable { + + /** + * reset the comparator. + */ + void reset(); Review comment: Because the field getter of currentRow may be cached. For example, the `UnboundedFollowingOverWindowFrame`, when calculating its tail boundary, may cross multiple Rows in iterator. The `BoundComparator.compare` will be invoked many times is the same `currentRow` input, so it is not necessary to get its field value every time, so cached its field value in `BoundComparator`. `reset` is designed to clear the cache of `BoundComparator`. ---------------------------------------------------------------- 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
