azagrebin commented on a change in pull request #6777: [FLINK-10461] [State Backends, Checkpointing] Speed up download files when restore from DFS URL: https://github.com/apache/flink/pull/6777#discussion_r228970609
########## File path: flink-state-backends/flink-statebackend-rocksdb/src/main/java/org/apache/flink/contrib/streaming/state/RocksDbStateDataTransfer.java ########## @@ -0,0 +1,149 @@ +/* + * 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.contrib.streaming.state; + +import org.apache.flink.core.fs.CloseableRegistry; +import org.apache.flink.core.fs.FSDataInputStream; +import org.apache.flink.core.fs.FSDataOutputStream; +import org.apache.flink.core.fs.FileSystem; +import org.apache.flink.core.fs.Path; +import org.apache.flink.runtime.concurrent.FutureUtils; +import org.apache.flink.runtime.state.IncrementalKeyedStateHandle; +import org.apache.flink.runtime.state.StateHandleID; +import org.apache.flink.runtime.state.StreamStateHandle; + +import java.io.Closeable; +import java.io.IOException; +import java.util.LinkedList; +import java.util.List; +import java.util.Map; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.Executors; + +/** + * Data transfer utils for RocksDbKeyedStateBackend. + */ +public class RocksDbStateDataTransfer { + + public static void transferAllStateDataToDirectory( + IncrementalKeyedStateHandle restoreStateHandle, + Path dest, + int resotreThreadNum, + CloseableRegistry closeableRegistry) throws Exception { + + final Map<StateHandleID, StreamStateHandle> sstFiles = + restoreStateHandle.getSharedState(); + final Map<StateHandleID, StreamStateHandle> miscFiles = + restoreStateHandle.getPrivateState(); + + transferAllDataFromStateHandles(sstFiles, dest, resotreThreadNum, closeableRegistry); + transferAllDataFromStateHandles(miscFiles, dest, resotreThreadNum, closeableRegistry); + } + + /** + * Copies all the files from the given stream state handles to the given path, renaming the files w.r.t. their + * {@link StateHandleID}. + */ + private static void transferAllDataFromStateHandles( + Map<StateHandleID, StreamStateHandle> stateHandleMap, + Path restoreInstancePath, + int resotreThreadNum, + CloseableRegistry closeableRegistry + ) throws Exception { + + final ExecutorService executorService = Executors.newFixedThreadPool(resotreThreadNum); + List<CompletableFuture<Void>> futures = new LinkedList<>(); + List<Closeable> closeables = new LinkedList<>(); + + try { + closeables.add(() -> executorService.shutdownNow()); + closeableRegistry.registerCloseable(((LinkedList<Closeable>) closeables).getLast()); + + for (Map.Entry<StateHandleID, StreamStateHandle> entry : stateHandleMap.entrySet()) { + StateHandleID stateHandleID = entry.getKey(); + StreamStateHandle remoteFileHandle = entry.getValue(); + + if (resotreThreadNum > 1) { + CompletableFuture<Void> future = CompletableFuture.runAsync(() -> { + try { + copyStateDataHandleData(new Path(restoreInstancePath, stateHandleID.toString()), remoteFileHandle, closeableRegistry); + } catch (IOException e) { Review comment: the exception handling can go inside `copyStateDataHandleData`. `new Path(restoreInstancePath, stateHandleID.toString())` can be a variable to reduce the line length. I would create a list of `Runnable`'s: ``` Path path = new Path(restoreInstancePath, stateHandleID.toString()); runnables.add( -> copyStateDataHandleData(path, remoteFileHandle, closeableRegistry)); ``` and then have separate code for `resotreThreadNum > 1` and `resotreThreadNum == 1`. `executorService` currently is not used for `resotreThreadNum == 1` but created. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on 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
