shahrs87 commented on a change in pull request #2945: URL: https://github.com/apache/hbase/pull/2945#discussion_r575028899
########## File path: hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationLogQueue.java ########## @@ -0,0 +1,182 @@ +/* + * 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 java.util.HashMap; +import java.util.Map; +import java.util.Queue; +import java.util.concurrent.PriorityBlockingQueue; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.fs.Path; +import org.apache.hadoop.hbase.util.EnvironmentEdgeManager; +import org.apache.hadoop.hbase.wal.AbstractFSWALProvider; +import org.apache.yetus.audience.InterfaceAudience; +import org.apache.yetus.audience.InterfaceStability; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/* + Class that does enqueueing/dequeueing of wal at one place so that we can update the metrics + just at one place. + */ +@InterfaceAudience.Private +@InterfaceStability.Evolving +public class ReplicationLogQueue { + // Queues of logs to process, entry in format of walGroupId->queue, + // each presents a queue for one wal group + private Map<String, PriorityBlockingQueue<Path>> queues = new HashMap<>(); + private MetricsSource metrics; + private Configuration conf; + // per group queue size, keep no more than this number of logs in each wal group + private int queueSizePerGroup; + // WARN threshold for the number of queued logs, defaults to 2 + private int logQueueWarnThreshold; + private ReplicationSource source; + private static final Logger LOG = LoggerFactory.getLogger(ReplicationSource.class); + + + public ReplicationLogQueue(Configuration conf, MetricsSource metrics, ReplicationSource source) { + this.conf = conf; + this.metrics = metrics; + this.source = source; + this.queueSizePerGroup = this.conf.getInt("hbase.regionserver.maxlogs", 32); + this.logQueueWarnThreshold = this.conf.getInt("replication.source.log.queue.warn", 2); + } + + /** + * Enqueue the wal + * @param wal wal to be enqueued + * @param walGroupId Key for the wal in @queues map + * @return boolean whether this is the first time we are seeing this walGroupId. + */ + public boolean enqueueLog(Path wal, String walGroupId) { + boolean exists = false; + PriorityBlockingQueue<Path> queue = queues.get(walGroupId); + if (queue == null) { + queue = new PriorityBlockingQueue<>(queueSizePerGroup, + new AbstractFSWALProvider.WALStartTimeComparator()); + // make sure that we do not use an empty queue when setting up a ReplicationSource, otherwise + // the shipper may quit immediately + queue.put(wal); + queues.put(walGroupId, queue); + } else { + exists = true; + queue.put(wal); + } + // Increment size of logQueue + this.metrics.incrSizeOfLogQueue(); + // Compute oldest wal age + setOldestWalAge(); + // This will wal a warning for each new wal that gets created above the warn threshold + int queueSize = queue.size(); + if (queueSize > this.logQueueWarnThreshold) { + LOG.warn("{} WAL group {} queue size: {} exceeds value of " + + "replication.source.log.queue.warn {}", source.logPeerId(), walGroupId, queueSize, + logQueueWarnThreshold); + } + return exists; + } + + /** + * Get the queue size for the given walGroupId. + * @param walGroupId walGroupId + */ + public int getQueueSize(String walGroupId) { + Queue queue = queues.get(walGroupId); + if (queue == null) { + return 0; + } + return queue.size(); + } + + /** + * Returns number of queues. + */ + public int getNumQueues() { + return queues.size(); + } + + public Map<String, PriorityBlockingQueue<Path>> getQueues() { + return queues; + } + + /** + * Return queue for the given walGroupId + * Please don't add or remove elements from the returned queue. + * Use @enqueueLog and @remove methods respectively. + * @param walGroupId walGroupId + */ + public PriorityBlockingQueue<Path> getQueue(String walGroupId) { + return queues.get(walGroupId); + } + + /** + * Remove head from the queue corresponding to given walGroupId. + * @param walGroupId walGroupId + */ + public void remove(String walGroupId) { + PriorityBlockingQueue<Path> queue = getQueue(walGroupId); + if (queue == null || queue.isEmpty()) { + return; + } + queue.remove(); + // Decrease size logQueue. + metrics.decrSizeOfLogQueue(); + // Re-compute age of oldest wal metric. + setOldestWalAge(); + } + + /** + * Remove all the elements from the queue corresponding to walGroupId + * @param walGroupId walGroupId + */ + public void clear(String walGroupId) { + PriorityBlockingQueue<Path> queue = getQueue(walGroupId); + while (!queue.isEmpty()) { + // Need to iterate since metrics#decrSizeOfLogQueue decrements just by 1. + queue.remove(); + metrics.decrSizeOfLogQueue(); + } + setOldestWalAge(); + } + + private void setOldestWalAge() { + long now = EnvironmentEdgeManager.currentTime(); + long timestamp = getOldestWalTimestamp(); + // TODO: Should we handle the case where getOldestWalTimestamp returns Long.MAX_VALUE ? + long age = now - timestamp; + this.metrics.setOldestWalAge(age); + } + + /* + Get the oldest wal timestamp from all the queues. + */ + private long getOldestWalTimestamp() { + long oldestWalTimestamp = Long.MAX_VALUE; + for (Map.Entry<String, PriorityBlockingQueue<Path>> entry : queues.entrySet()) { Review comment: Yes. That is the reason I was ok with O(n) loop. ---------------------------------------------------------------- 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
