stevenzwu commented on code in PR #6160: URL: https://github.com/apache/iceberg/pull/6160#discussion_r1128200547
########## flink/v1.16/flink/src/main/java/org/apache/iceberg/flink/source/assigner/LocalitySplitAssigner.java: ########## @@ -0,0 +1,165 @@ +/* + * 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.iceberg.flink.source.assigner; + +import java.util.ArrayDeque; +import java.util.Collection; +import java.util.Deque; +import java.util.Iterator; +import java.util.Map; +import java.util.Set; +import java.util.concurrent.CompletableFuture; +import java.util.stream.Collectors; +import java.util.stream.Stream; +import javax.annotation.Nullable; +import org.apache.flink.annotation.Internal; +import org.apache.iceberg.flink.source.split.IcebergSourceSplit; +import org.apache.iceberg.flink.source.split.IcebergSourceSplitState; +import org.apache.iceberg.flink.source.split.IcebergSourceSplitStatus; +import org.apache.iceberg.relocated.com.google.common.collect.Maps; +import org.apache.iceberg.relocated.com.google.common.collect.Sets; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +@Internal +public class LocalitySplitAssigner implements SplitAssigner { + private static final Logger LOG = LoggerFactory.getLogger(LocalitySplitAssigner.class); + + private static final String DEFAULT_HOSTNAME = "hostname"; + private final Map<Set<String>, Deque<IcebergSourceSplit>> pendingSplits; + private CompletableFuture<Void> availableFuture; + + public LocalitySplitAssigner() { + this.pendingSplits = Maps.newHashMap(); + } + + public LocalitySplitAssigner(Collection<IcebergSourceSplitState> assignerState) { + this.pendingSplits = Maps.newHashMap(); + Stream<IcebergSourceSplit> splits = assignerState.stream().map(IcebergSourceSplitState::split); + addSplits(splits.collect(Collectors.toList())); + } + + @Override + public GetSplitResult getNext(@Nullable String hostname) { + if (pendingSplits.isEmpty()) { + return GetSplitResult.unavailable(); + } + + Deque<IcebergSourceSplit> icebergSourceSplits = + hostname == null + ? getIcebergSourceSplits(DEFAULT_HOSTNAME, pendingSplits) + : getIcebergSourceSplits(hostname, pendingSplits); + LOG.info("Get Iceberg source splits for: {}", hostname); + + if (!icebergSourceSplits.isEmpty()) { + IcebergSourceSplit split = icebergSourceSplits.poll(); + return GetSplitResult.forSplit(split); + } + + return GetSplitResult.unavailable(); + } + + private Deque<IcebergSourceSplit> getIcebergSourceSplits( + String hostname, Map<Set<String>, Deque<IcebergSourceSplit>> splitsDeque) { + if (splitsDeque.isEmpty()) { + return new ArrayDeque<>(); + } + + Iterator<Map.Entry<Set<String>, Deque<IcebergSourceSplit>>> splitsIterator = + splitsDeque.entrySet().iterator(); + while (splitsIterator.hasNext()) { Review Comment: the pseudo algo looks ok to me. BTW, for locality aware assigner, does it mean that `CombinedScanTask` is better to just contain one file? do we need to decompose it to individual files? E.g., a combined task contains 3 files: f1(h1, h2, h3), f2(h4, h5, h6), f3(h7, h8, h9). But the downside would be more smaller splits. so there is a tradeoff here. not sure what is the typical preference in HDFS scenario. -- 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: issues-unsubscr...@iceberg.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
