Apache9 commented on code in PR #4556: URL: https://github.com/apache/hbase/pull/4556#discussion_r907951846
########## hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationMarkerChore.java: ########## @@ -0,0 +1,118 @@ +/* + * 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.hbase.replication.regionserver; + +import static org.apache.hadoop.hbase.replication.master.ReplicationSinkTrackerTableCreator.REPLICATION_SINK_TRACKER_TABLE_NAME; + +import java.io.IOException; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.hbase.ScheduledChore; +import org.apache.hadoop.hbase.Stoppable; +import org.apache.hadoop.hbase.client.RegionInfo; +import org.apache.hadoop.hbase.client.RegionInfoBuilder; +import org.apache.hadoop.hbase.regionserver.MultiVersionConcurrencyControl; +import org.apache.hadoop.hbase.regionserver.RegionServerServices; +import org.apache.hadoop.hbase.regionserver.wal.WALUtil; +import org.apache.hadoop.hbase.util.Bytes; +import org.apache.hadoop.hbase.util.EnvironmentEdgeManager; +import org.apache.hadoop.hbase.wal.WAL; +import org.apache.hadoop.hbase.wal.WALEdit; +import org.apache.yetus.audience.InterfaceAudience; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * This chore is responsible to create replication marker rows with special WALEdit with family as + * {@link org.apache.hadoop.hbase.wal.WALEdit#METAFAMILY} and column qualifier as + * {@link WALEdit#REPLICATION_MARKER} and empty value. If config key + * {@link #REPLICATION_MARKER_ENABLED_KEY} is set to true, then we will create 1 marker row every + * {@link #REPLICATION_MARKER_CHORE_DURATION_KEY} ms + * {@link org.apache.hadoop.hbase.replication.regionserver.ReplicationSourceWALReader} will populate + * the Replication Marker edit with region_server_name, wal_name and wal_offset encoded in + * {@link org.apache.hadoop.hbase.shaded.protobuf.generated.WALProtos.ReplicationMarkerDescriptor} + * object. {@link org.apache.hadoop.hbase.replication.regionserver.Replication} will change the + * REPLICATION_SCOPE for this edit to GLOBAL so that it can replicate. On the sink cluster, + * {@link org.apache.hadoop.hbase.replication.regionserver.ReplicationSink} will convert the + * ReplicationMarkerDescriptor into a Put mutation to REPLICATION_SINK_TRACKER_TABLE_NAME_STR table. + */ [email protected] +public class ReplicationMarkerChore extends ScheduledChore { + private static final Logger LOG = LoggerFactory.getLogger(ReplicationMarkerChore.class); + private static final MultiVersionConcurrencyControl MVCC = new MultiVersionConcurrencyControl(); + public static final RegionInfo REGION_INFO = + RegionInfoBuilder.newBuilder(REPLICATION_SINK_TRACKER_TABLE_NAME).build(); + private static final String DELIMITER = "_"; + private final Configuration conf; + private final RegionServerServices rsServices; + private WAL wal; + + public static final String REPLICATION_MARKER_ENABLED_KEY = + "hbase.regionserver.replication.marker.enabled"; + public static final boolean REPLICATION_MARKER_ENABLED_DEFAULT = false; + + public static final String REPLICATION_MARKER_CHORE_DURATION_KEY = + "hbase.regionserver.replication.marker.chore.duration"; + public static final int REPLICATION_MARKER_CHORE_DURATION_DEFAULT = 30 * 1000; // 30 seconds + + public ReplicationMarkerChore(final Stoppable stopper, final RegionServerServices rsServices, + int period, Configuration conf) { + super("ReplicationTrackerChore", stopper, period); + this.conf = conf; + this.rsServices = rsServices; + } + + @Override + protected void chore() { + if (wal == null) { + try { + wal = rsServices.getWAL(null); + } catch (IOException ioe) { + LOG.warn("Unable to get WAL ", ioe); + // Shouldn't happen. Ignore and wait for the next chore run. + return; + } + } + String serverName = rsServices.getServerName().getServerName(); + long timeStamp = EnvironmentEdgeManager.currentTime(); + // We only have timestamp in ReplicationMarkerDescriptor and the remaining properties walname, + // regionserver name and wal offset at ReplicationSourceWALReaderThread. + byte[] rowKey = getRowKey(serverName, timeStamp); + if (LOG.isTraceEnabled()) { + LOG.trace("Creating replication marker edit."); + } + try { + WALUtil.writeReplicationMarkerAndSync(wal, MVCC, REGION_INFO, rowKey, timeStamp); Review Comment: > > If we only use table name in this method, then better just pass a table name in. > > All the methods which are used to sync the marker rows expect regioninfo parameter. For e.g `WALUtil#writeMarker` [here](https://github.com/apache/hbase/blob/master/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/WALUtil.java#L139) Also the API to append marker row to WAL uses regioninfo. Refer [here](https://github.com/apache/hbase/blob/master/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/AbstractFSWAL.java#L1257) That's the problem here... We need to pass a region info in, so we hard coded a region info, which implies that this table only has one region, while it is actually not... And this makes me a bit worry that, actually we do not hold this region on the region server, but then we write a WAL which is for this region, I'm afraid in the future if other developers add some sanity checks in the WAL implementation and then it will break this feature... -- 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]
