GeorgeJahad commented on code in PR #3885: URL: https://github.com/apache/ozone/pull/3885#discussion_r1018514954
########## hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/snapshot/SnapshotDiffManager.java: ########## @@ -0,0 +1,235 @@ +/* + * 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 + * <p> + * http://www.apache.org/licenses/LICENSE-2.0 + * <p> + * 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.om.snapshot; + +import org.apache.hadoop.hdds.utils.db.Table; +import org.apache.hadoop.ozone.om.OMMetadataManager; +import org.apache.hadoop.ozone.om.OmSnapshot; +import org.apache.hadoop.ozone.om.helpers.BucketLayout; +import org.apache.hadoop.ozone.om.helpers.OmKeyInfo; +import org.apache.hadoop.ozone.om.snapshot.SnapshotDiffReport.DiffType; +import org.apache.hadoop.ozone.om.snapshot.SnapshotDiffReport.DiffReportEntry; + +import org.apache.ozone.rocksdb.util.ManagedSstFileReader; +import org.apache.ozone.rocksdb.util.RdbUtil; +import org.rocksdb.RocksDBException; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.HashMap; +import java.util.HashSet; +import java.util.List; +import java.util.Map; +import java.util.Set; +import java.util.stream.Stream; + +/** + * Class to generate snapshot diff. + */ +public class SnapshotDiffManager { + + public SnapshotDiffReport getSnapshotDiffReport(final String volume, + final String bucket, + final OmSnapshot fromSnapshot, + final OmSnapshot toSnapshot) + throws IOException, RocksDBException { + + // TODO: Once RocksDBCheckpointDiffer exposes method to get list + // of delta SST files, plug it in here. + + Set<String> fromSnapshotFiles = RdbUtil.getKeyTableSSTFiles(fromSnapshot + .getMetadataManager().getStore().getDbLocation().getPath()); + Set<String> toSnapshotFiles = RdbUtil.getKeyTableSSTFiles(toSnapshot + .getMetadataManager().getStore().getDbLocation().getPath()); + + final Set<String> deltaFiles = new HashSet<>(); + deltaFiles.addAll(fromSnapshotFiles); + deltaFiles.addAll(toSnapshotFiles); + + // TODO: Filter out the files. + + final Stream<String> keysToCheck = new ManagedSstFileReader(deltaFiles) + .getKeyStream(); + + final BucketLayout bucketLayout = getBucketLayout(volume, bucket, + fromSnapshot.getMetadataManager()); + + final Table<String, OmKeyInfo> fsKeyTable = fromSnapshot + .getMetadataManager().getKeyTable(bucketLayout); + final Table<String, OmKeyInfo> tsKeyTable = toSnapshot + .getMetadataManager().getKeyTable(bucketLayout); + + /* + * The reason for having ObjectID to KeyName mapping instead of OmKeyInfo + * is to reduce the memory footprint. + */ + final Map<Long, String> oldObjIdToKeyMap = new HashMap<>(); + // Long --> const. length + // String --> var. length "/dir1/dir2/dir3/dir4/dir5/key1" + final Map<Long, String> newObjIdToKeyMap = new HashMap<>(); + Review Comment: It looks like these hashmaps need to simultaneously store every key being diffed. Is that correct? So if each entry is 100 bytes, and there are 10 million keys being diffed, that is 1 gig of memory per hashmap. Is that acceptable? -- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
