Github user tillrohrmann commented on a diff in the pull request: https://github.com/apache/flink/pull/5487#discussion_r170013389 --- Diff: flink-runtime/src/main/java/org/apache/flink/runtime/jobmaster/RescalingBehaviour.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.runtime.jobmaster; + +import org.apache.flink.runtime.jobgraph.JobVertex; +import org.apache.flink.util.FlinkException; +import org.apache.flink.util.function.BiConsumerWithException; + +/** + * Definition of the rescaling behaviour. + */ +public enum RescalingBehaviour implements BiConsumerWithException<JobVertex, Integer, FlinkException> { + // rescaling is only executed if the operator can be set to the given parallelism + STRICT { + @Override + public void acceptWithException(JobVertex jobVertex, Integer newParallelism) throws FlinkException { + if (jobVertex.getMaxParallelism() < newParallelism) { + throw new FlinkException("Cannot rescale vertex " + jobVertex.getName() + + " because its maximum parallelism " + jobVertex.getMaxParallelism() + + " is smaller than the new parallelism " + newParallelism + '.'); + } else { + jobVertex.setParallelism(newParallelism); + } + } + }, + // the new parallelism will be the minimum of the given parallelism and the maximum parallelism + RELAXED { --- End diff -- Yes
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