| deniskuzZ commented on code in PR #3303:
URL: https://github.com/apache/hive/pull/3303#discussion_r909292463 ##########
ql/src/java/org/apache/hadoop/hive/ql/txn/compactor/CompactionHeartbeatService.java:
##########
@@ -0,0 +1,213 @@
+/*
+ * 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.hive.ql.txn.compactor;
+
+import org.apache.commons.pool2.ObjectPool;
+import org.apache.commons.pool2.impl.GenericObjectPool;
+import org.apache.commons.pool2.impl.GenericObjectPoolConfig;
+import org.apache.hadoop.hive.conf.HiveConf;
+import org.apache.hadoop.hive.metastore.IMetaStoreClient;
+import org.apache.hadoop.hive.metastore.conf.MetastoreConf;
+import org.apache.hive.common.util.ShutdownHookManager;
+import org.apache.thrift.TException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.NoSuchElementException;
+import java.util.Objects;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+
+import static org.apache.hive.common.util.HiveStringUtils.SHUTDOWN_HOOK_PRIORITY;
+
+/**
+ * Singleton service responsible for heartbeating the compaction transactions.
+ */
+class CompactionHeartbeatService {
+
+
+ private static final Logger LOG = LoggerFactory.getLogger(CompactionHeartbeatService.class);
+
+ private static volatile CompactionHeartbeatService instance;
+
+ /**
+ * Return the singleton instance of this class.
+ * @param conf The {@link HiveConf} used to create the service. Used only during the firsst call
+ * @return Returns the singleton {@link CompactionHeartbeatService} + * @throws IllegalStateException Thrown when the service has already been destroyed.
+ */
+ static CompactionHeartbeatService getInstance(HiveConf conf) {
+ if (instance == null) {
+ synchronized (CompactionHeartbeatService.class) {
+ if (instance == null) { + LOG.debug("Initializing compaction txn heartbeater service."); + instance = new CompactionHeartbeatService(conf); + ShutdownHookManager.addShutdownHook(() -> instance.shutdown(), SHUTDOWN_HOOK_PRIORITY); + } + }
+ }
+ if (instance.shuttingDown) { + throw new IllegalStateException("The CompactionHeartbeatService is already destroyed!"); + } + return instance;
+ }
+
+ private final ObjectPool<IMetaStoreClient> clientPool;
+ private volatile boolean shuttingDown = false;
+ private final long initialDelay;
+ private final long period;
+ private final ConcurrentHashMap<Long, CompactionHeartbeater> tasks = new ConcurrentHashMap<>(30);
+
+ /**
+ * Starts the heartbeat for the given transaction
+ * @param txnId The id of the compaction txn
+ * @param lockId The id of the lock associated with the txn
+ * @param tableName Required for logging only
+ * @throws IllegalStateException Thrown when the heartbeat for the given txn has already been started.
+ */
+ void startHeartbeat(long txnId, long lockId, String tableName) {
+ if (shuttingDown) { + throw new IllegalStateException("Service is shutting down, starting new heartbeats are not possible!"); + } + if (tasks.containsKey(txnId)) { + throw new IllegalStateException("Heartbeat was already started for TXN " + txnId); + } + LOG.info("Submitting heartbeat task for TXN {}", txnId);
+ CompactionHeartbeater heartbeater = new CompactionHeartbeater(txnId, lockId, tableName);
+ heartbeater.start();
+ tasks.put(txnId, heartbeater);
+ }
+
+ /**
+ * Stops the heartbeat for the given transaction
+ * @param txnId The id of the compaction txn
+ * @throws IllegalStateException Thrown when there is no {@link CompactionHeartbeater} task associated with the
+ * given txnId.
+ */
+ void stopHeartbeat(long txnId) {
+ LOG.info("Stopping heartbeat task for TXN {}", txnId);
+ CompactionHeartbeater heartbeater = tasks.get(txnId);
+ if (heartbeater == null) { + throw new IllegalStateException("No registered heartbeat found for TXN " + txnId); + } + try { + heartbeater.stop(); + } finally { + tasks.remove(txnId); + }
+ }
+
+ /**
+ * Shuts down the service, by closing its underlying resources. Be aware that after shutdown this service is no
+ * longer usable, there is no way to re-initialize it.
+ */
+ void shutdown() {
+ shuttingDown = true;
+ LOG.info("Shutting down compaction txn heartbeater service.");
+ for (CompactionHeartbeater heartbeater : tasks.values()) {+ heartbeater.stop();+ } + tasks.clear();
+ clientPool.close();
+ LOG.info("Compaction txn heartbeater service is successfully stopped.");
+ }
+
+ private CompactionHeartbeatService(HiveConf conf) { + int numberOfWorkers = MetastoreConf.getIntVar(conf, MetastoreConf.ConfVars.COMPACTOR_WORKER_THREADS); + GenericObjectPoolConfig<IMetaStoreClient> config = new GenericObjectPoolConfig<>(); + config.setMinIdle(1); + config.setMaxIdle(2); + config.setMaxTotal(numberOfWorkers); + config.setMaxWaitMillis(2000); + clientPool = new GenericObjectPool<>(new IMetaStoreClientFactory(conf), config); + long txnTimeout = MetastoreConf.getTimeVar(conf, MetastoreConf.ConfVars.TXN_TIMEOUT, TimeUnit.MILLISECONDS); + initialDelay = txnTimeout / 4; + period = txnTimeout / 2; + } +
+ private final class CompactionHeartbeater {
+ private final Logger LOG = LoggerFactory.getLogger(CompactionHeartbeater.class);
+ private final long txnId;
+ private final long lockId;
+ private final String tableName;
+ private final ScheduledThreadPoolExecutor heartbeatExecutor;
+
+ private CompactionHeartbeater(long txnId, long lockId, String tableName) { + heartbeatExecutor = new ScheduledThreadPoolExecutor(1); + this.tableName = Objects.requireNonNull(tableName); + this.txnId = txnId; + this.lockId = lockId; + } +
+ void start() {
+ heartbeatExecutor.scheduleAtFixedRate(() -> {
+ IMetaStoreClient msc = null;
+ try {
+ LOG.debug("Heartbeating compaction transaction id {} for table: {}", txnId, tableName);
+ // Create a metastore client for each thread since it is not thread safe
+ msc = clientPool.borrowObject();
+ msc.heartbeat(txnId, lockId);
+ } catch (NoSuchElementException e) { + LOG.error("Compaction transaction heartbeater pool exhausted, unable to heartbeat", e); + // This heartbeat attempt failed, and there is no client to return to the pool. + return; + } catch (TException e) {
+ LOG.error("Error while heartbeating compaction transaction id {} for table: {}", txnId, tableName, e);
+ // Heartbeat failed, but the client is not broken, we can return it to the pool.
+ } catch (Exception e) {
+ LOG.error("Error while heartbeating compaction transaction id {} for table: {}", txnId, tableName, e);
+ // Unknown error, invalidate the client, maybe it is broken.
+ if (msc != null) {
+ try { + clientPool.invalidateObject(msc); + } catch (Exception ex) { + LOG.error("Error while invalidating a broken MetaStoreClient instance", e); + } + }
+ return;
+ }
+ try {
+ if (msc != null) { + clientPool.returnObject(msc); + } + } catch (Exception e) { + LOG.error("Error while invalidating a broken MetaStoreClient instance", e); + } + }, initialDelay, period, TimeUnit.MILLISECONDS);
+ }
+
+ public void stop() {
+ LOG.info("Shutting down compaction txn heartbeater instance.");
+ heartbeatExecutor.shutdownNow();
+ try {
+ if (!heartbeatExecutor.awaitTermination(5, TimeUnit.SECONDS)) {
+ LOG.warn("Heartbeating for transaction {} did not stop in 5 seconds, do not wait any longer.", this);
+ return;
+ }
+ } catch (InterruptedException ex) {
+ //Caller thread was interrupted while waiting for heartbeater to terminate.
+ //Nothing to do, just restore the interrupted state.
+ Thread.currentThread().interrupt(); Review Comment:
how would it behave in case shutdownhook is invoked? would it interrupt the shutdownhook thread? |
