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.replication.regionserver;
019
020import java.util.Collections;
021import org.apache.hadoop.hbase.wal.AbstractFSWALProvider;
022import org.apache.yetus.audience.InterfaceAudience;
023
024/**
025 * ReplicationSource that reads catalog WAL files -- e.g. hbase:meta WAL files -- and lets through
026 * all WALEdits from these WALs. This ReplicationSource is NOT created via
027 * {@link ReplicationSourceFactory}.
028 */
029@InterfaceAudience.Private
030class CatalogReplicationSource extends ReplicationSource {
031  CatalogReplicationSource() {
032    // Filters in hbase:meta WAL files and allows all edits, including 'meta' edits (these are
033    // filtered out in the 'super' class default implementation).
034    super(p -> AbstractFSWALProvider.isMetaFile(p), Collections.emptyList());
035  }
036
037  @Override
038  public void logPositionAndCleanOldLogs(WALEntryBatch entryBatch) {
039    // Noop. This CatalogReplicationSource implementation does not persist state to backing storage
040    // nor does it keep its WALs in a general map up in ReplicationSourceManager --
041    // CatalogReplicationSource is used by the Catalog Read Replica feature which resets everytime
042    // the WAL source process crashes. Skip calling through to the default implementation.
043    // See "4.1 Skip maintaining zookeeper replication queue (offsets/WALs)" in the
044    // design doc attached to HBASE-18070 'Enable memstore replication for meta replica for detail'
045    // for background on why no need to keep WAL state.
046  }
047}