001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.regionserver.storefiletracker;
019
020import java.io.IOException;
021import java.util.Collection;
022import java.util.List;
023import org.apache.hadoop.fs.FileStatus;
024import org.apache.hadoop.fs.Path;
025import org.apache.hadoop.hbase.TableName;
026import org.apache.hadoop.hbase.client.TableDescriptorBuilder;
027import org.apache.hadoop.hbase.io.Reference;
028import org.apache.hadoop.hbase.regionserver.CreateStoreFileWriterParams;
029import org.apache.hadoop.hbase.regionserver.StoreFileInfo;
030import org.apache.hadoop.hbase.regionserver.StoreFileWriter;
031import org.apache.yetus.audience.InterfaceAudience;
032
033/**
034 * An interface to define how we track the store files for a give store.
035 * <p/>
036 * In the old time, we will write store to a tmp directory first, and then rename it to the actual
037 * data file. And once a store file is under data directory, we will consider it as 'committed'. And
038 * we need to do listing when loading store files.
039 * <p/>
040 * When cloud age is coming, now we want to store the store files on object storage, where rename
041 * and list are not as cheap as on HDFS, especially rename. Although introducing a metadata
042 * management layer for object storage could solve the problem, but we still want HBase to run on
043 * pure object storage, so here we introduce this interface to abstract how we track the store
044 * files. For the old implementation, we just persist nothing here, and do listing to load store
045 * files. When running on object storage, we could persist the store file list in a system region,
046 * or in a file on the object storage, to make it possible to write directly into the data directory
047 * to avoid renaming, and also avoid listing when loading store files.
048 * <p/>
049 * The implementation requires to be thread safe as flush and compaction may occur as the same time,
050 * and we could also do multiple compactions at the same time. As the implementation may choose to
051 * persist the store file list to external storage, which could be slow, it is the duty for the
052 * callers to not call it inside a lock which may block normal read/write requests.
053 */
054@InterfaceAudience.Private
055public interface StoreFileTracker {
056  /**
057   * Load the store files list when opening a region.
058   */
059  List<StoreFileInfo> load() throws IOException;
060
061  /**
062   * Add new store files.
063   * <p/>
064   * Used for flush and bulk load.
065   */
066  void add(Collection<StoreFileInfo> newFiles) throws IOException;
067
068  /**
069   * Add new store files and remove compacted store files after compaction.
070   */
071  void replace(Collection<StoreFileInfo> compactedFiles, Collection<StoreFileInfo> newFiles)
072    throws IOException;
073
074  /**
075   * Set the store files.
076   */
077  void set(List<StoreFileInfo> files) throws IOException;
078
079  /**
080   * Create a writer for writing new store files.
081   * @return Writer for a new StoreFile
082   */
083  StoreFileWriter createWriter(CreateStoreFileWriterParams params) throws IOException;
084
085  /**
086   * Adds StoreFileTracker implementations specific configurations into the table descriptor.
087   * <p/>
088   * This is used to avoid accidentally data loss when changing the cluster level store file tracker
089   * implementation, and also possible misconfiguration between master and region servers.
090   * <p/>
091   * See HBASE-26246 for more details.
092   * @param builder The table descriptor builder for the given table.
093   */
094  TableDescriptorBuilder updateWithTrackerConfigs(TableDescriptorBuilder builder);
095
096  /**
097   * Whether the implementation of this tracker requires you to write to temp directory first, i.e,
098   * does not allow broken store files under the actual data directory.
099   */
100  boolean requireWritingToTmpDirFirst();
101
102  Reference createReference(Reference reference, Path path) throws IOException;
103
104  /**
105   * Reads the reference file from the given path.
106   * @param path the {@link Path} to the reference file in the file system.
107   * @return a {@link Reference} that points at top/bottom half of a an hfile
108   */
109  Reference readReference(Path path) throws IOException;
110
111  /**
112   * Returns true if the specified family has reference files
113   * @return true if family contains reference files
114   */
115  boolean hasReferences() throws IOException;
116
117  StoreFileInfo getStoreFileInfo(final FileStatus fileStatus, final Path initialPath,
118    final boolean primaryReplica) throws IOException;
119
120  StoreFileInfo getStoreFileInfo(final Path initialPath, final boolean primaryReplica)
121    throws IOException;
122
123  /**
124   * Create a new HFileLink
125   * <p>
126   * It also adds a back-reference to the hfile back-reference directory to simplify the
127   * reference-count and the cleaning process.
128   * @param hfileLinkName - HFileLink name (it contains hfile-region-table)
129   * @param createBackRef - Whether back reference should be created. Defaults to true.
130   * @return the file link name.
131   * @throws IOException on file or parent directory creation failure.
132   */
133  String createHFileLink(final TableName linkedTable, final String linkedRegion,
134    final String hfileName, final boolean createBackRef) throws IOException;
135
136  /**
137   * Create a new HFileLink starting from a hfileLink name
138   * <p>
139   * It also adds a back-reference to the hfile back-reference directory to simplify the
140   * reference-count and the cleaning process.
141   * @param hfileLinkName - HFileLink name (it contains hfile-region-table)
142   * @param createBackRef - Whether back reference should be created. Defaults to true.
143   * @return the file link name.
144   * @throws IOException on file or parent directory creation failure.
145   */
146  String createFromHFileLink(final String hfileName, final boolean createBackRef)
147    throws IOException;
148
149}