JingsongLi commented on code in PR #1072: URL: https://github.com/apache/incubator-paimon/pull/1072#discussion_r1186649329
########## paimon-core/src/main/java/org/apache/paimon/utils/ParallellyExecuteUtils.java: ########## @@ -0,0 +1,92 @@ +/* + * 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.paimon.utils; + +import org.apache.paimon.shade.guava30.com.google.common.collect.Lists; + +import java.util.ArrayDeque; +import java.util.Iterator; +import java.util.List; +import java.util.NoSuchElementException; +import java.util.Queue; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.ExecutionException; +import java.util.function.Function; + +/** + * This class is a parallel execution util class, which mainly aim to process tasks parallelly with + * memory control. + */ +public class ParallellyExecuteUtils { + + // reduce memory usage by batch iterable process, the cached result in memory will be queueSize + public static <T, U> Iterable<T> parallelismBatchIterable( + Function<List<U>, List<T>> processor, List<U> input, Integer queueSize) { + if (queueSize == null) { + queueSize = FileUtils.COMMON_IO_FORK_JOIN_POOL.getParallelism(); + } else if (queueSize <= 0) { + throw new NegativeArraySizeException("queue size should not be negetive"); + } + + final Queue<List<U>> stack = new ArrayDeque<>(Lists.partition(input, queueSize)); + + return () -> + new Iterator<T>() { + List<T> activeList = null; + private int index = 0; + + @Override + public boolean hasNext() { + advanceIfNeeded(); + return activeList != null && index < activeList.size(); + } + + @Override + public T next() { + advanceIfNeeded(); + if (activeList == null || index >= activeList.size()) { + throw new NoSuchElementException(); + } + return activeList.get(index++); + } + + private void advanceIfNeeded() { + if ((activeList == null || index >= activeList.size()) + && stack.size() > 0) { + // reset index + index = 0; + try { + activeList = + CompletableFuture.supplyAsync( + () -> processor.apply(stack.poll()), + FileUtils.COMMON_IO_FORK_JOIN_POOL) + .get(); + } catch (InterruptedException e) { Review Comment: Just ``` } catch (Exception e) { throw new RuntimeException(e); } ``` ? - Swallow `InterruptedException` is not good. - Exception message is confused, `"should never get here"`, IOException will go here. -- 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]
