adoroszlai commented on a change in pull request #7: HDDS-1228. Chunk Scanner Checkpoints URL: https://github.com/apache/hadoop-ozone/pull/7#discussion_r337399474
########## File path: hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/impl/ContainerDataScanOrder.java ########## @@ -0,0 +1,57 @@ +/* + * 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.hadoop.ozone.container.common.impl; + +import org.apache.hadoop.ozone.container.common.interfaces.Container; + +import java.time.Instant; +import java.util.Comparator; +import java.util.Optional; + +/** + * Orders containers: + * 1. containers not yet scanned first, + * 2. then least recently scanned first, + * 3. ties are broken by containerID. + */ +public class ContainerDataScanOrder implements Comparator<Container<?>> { + + public static final Comparator<Container<?>> INSTANCE = + new ContainerDataScanOrder(); + + @Override + public int compare(Container<?> o1, Container<?> o2) { + ContainerData d1 = o1.getContainerData(); + ContainerData d2 = o2.getContainerData(); + + Optional<Instant> scan1 = d1.lastDataScanTime(); + boolean scanned1 = scan1.isPresent(); + Optional<Instant> scan2 = d2.lastDataScanTime(); + boolean scanned2 = scan2.isPresent(); + + int result = Boolean.compare(scanned1, scanned2); + if (0 == result && scanned1 && scanned2) { + result = scan1.get().compareTo(scan2.get()); + } + if (0 == result) { + result = Long.compare(d1.getContainerID(), d2.getContainerID()); Review comment: Thanks @arp7 for reviewing it again. The first check compares presence of scan timestamps and takes care of the case you mention: https://github.com/apache/hadoop-ozone/blob/019f5d313bea56ec3009fbe9f773d21a85cfe54b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/impl/ContainerDataScanOrder.java#L47 The unit test also checks it: https://github.com/apache/hadoop-ozone/blob/019f5d313bea56ec3009fbe9f773d21a85cfe54b/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/impl/TestContainerSet.java#L212-L224 ---------------------------------------------------------------- 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 --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-dev-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-dev-h...@hadoop.apache.org
