architjainjain commented on code in PR #6501:
URL: https://github.com/apache/hive/pull/6501#discussion_r3674399624
##########
service/src/java/org/apache/hive/service/server/HiveServer2.java:
##########
@@ -966,6 +970,20 @@ private void initAndStartWorkloadManager(final
WMFullResourcePlan resourcePlan)
}
}
+ /**
+ * Initializes the queue metrics refresh pool and HTTP exporter.
+ * Failures are non-fatal — logged as warnings so the server can start
without queue metrics.
+ */
+ private void initializeQueueMetricsPool(HiveConf hiveConf) {
Review Comment:
done
##########
ql/src/java/org/apache/hadoop/hive/ql/exec/tez/monitoring/yarnqueue/QueueMetricsRefreshPool.java:
##########
@@ -0,0 +1,146 @@
+/*
+ * 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.exec.tez.monitoring.yarnqueue;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.util.concurrent.ThreadFactoryBuilder;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * Singleton manager for the JVM-wide refresh executor pool used by queue
metrics collection.
+ * Provides a shared {@link ScheduledExecutorService} that fires periodic YARN
RM refresh tasks
+ * across all queries in the HiveServer2 process.
+ * <p>
+ * Initialized during HiveServer2 startup via {@link #init(int)} when Tez
session pool is set up.
+ * Pool size is configured via {@code
hive.server2.tez.queue.metrics.refresh.threads} (default: 4).
+ * <p>
+ * All {@link YarnQueueMetricsCollector} instances share this single pool,
ensuring efficient
+ * resource usage and preventing thread explosion when many queries run
concurrently.
+ * <p>
+ * Thread-safe singleton implementation using double-check locking pattern.
+ */
+public final class QueueMetricsRefreshPool {
+ private static final Logger LOG =
LoggerFactory.getLogger(QueueMetricsRefreshPool.class);
+
+ private static final int DEFAULT_THREAD_COUNT = 4;
+ public static final int JITTER_PERCENT = 10;
+
+ private static final AtomicReference<QueueMetricsRefreshPool> INSTANCE = new
AtomicReference<>(null);
+ private static final Object INIT_LOCK = new Object();
+
+ private final ScheduledExecutorService refreshPool;
+
+
+ /**
+ * Initializes the singleton pool with the specified thread count.
+ * Must be called during HiveServer2 startup. Subsequent calls are ignored.
+ *
+ * @param threadCount number of threads for the refresh pool
+ */
+ public static void init(int threadCount) {
+ if (INSTANCE.get() != null) {
+ LOG.debug("QueueMetricsRefreshPool already initialized, ignoring init
call");
+ return;
+ }
+ synchronized (INIT_LOCK) {
+ if (INSTANCE.get() == null) {
+ INSTANCE.set(new QueueMetricsRefreshPool(threadCount));
+ }
+ }
+ }
+
+ /**
+ * Returns the singleton instance. Must be called after {@link #init(int)}.
+ * For tests or non-HS2 environments, lazily initializes with default thread
count.
+ *
+ * @return the singleton pool instance
+ */
+ public static QueueMetricsRefreshPool getInstance() {
+ QueueMetricsRefreshPool local = INSTANCE.get();
+ if (local != null) {
+ return local;
+ }
+ // Lazy init for tests/non-HS2 with default thread count
+ synchronized (INIT_LOCK) {
+ local = INSTANCE.get();
+ if (local == null) {
+ LOG.warn("QueueMetricsRefreshPool not initialized via init(), using
default thread count: {}",
+ DEFAULT_THREAD_COUNT);
+ local = new QueueMetricsRefreshPool(DEFAULT_THREAD_COUNT);
+ INSTANCE.set(local);
+ }
+ return local;
+ }
+ }
+
+
+ private QueueMetricsRefreshPool(int threadCount) {
+ this.refreshPool = Executors.newScheduledThreadPool(threadCount,
+ new ThreadFactoryBuilder()
+ .setNameFormat("queue-metrics-refresh-%d")
+ .setDaemon(true)
+ .build());
+ LOG.info("QueueMetricsRefreshPool initialized with {} threads",
threadCount);
+ }
+
+
+ /**
+ * Schedules a periodic refresh task. initialDelay=0 so the first fetch runs
immediately.
+ */
+ public ScheduledFuture<Void> scheduleRefreshTask(Runnable task, long
intervalMs) {
+ return (ScheduledFuture<Void>) refreshPool.scheduleWithFixedDelay(task, 0,
intervalMs, TimeUnit.MILLISECONDS);
+ }
Review Comment:
done
##########
ql/src/java/org/apache/hadoop/hive/ql/exec/tez/monitoring/yarnqueue/QueueMetricsRefreshPool.java:
##########
@@ -0,0 +1,146 @@
+/*
+ * 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.exec.tez.monitoring.yarnqueue;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.util.concurrent.ThreadFactoryBuilder;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * Singleton manager for the JVM-wide refresh executor pool used by queue
metrics collection.
+ * Provides a shared {@link ScheduledExecutorService} that fires periodic YARN
RM refresh tasks
+ * across all queries in the HiveServer2 process.
+ * <p>
+ * Initialized during HiveServer2 startup via {@link #init(int)} when Tez
session pool is set up.
+ * Pool size is configured via {@code
hive.server2.tez.queue.metrics.refresh.threads} (default: 4).
+ * <p>
+ * All {@link YarnQueueMetricsCollector} instances share this single pool,
ensuring efficient
+ * resource usage and preventing thread explosion when many queries run
concurrently.
+ * <p>
+ * Thread-safe singleton implementation using double-check locking pattern.
+ */
+public final class QueueMetricsRefreshPool {
+ private static final Logger LOG =
LoggerFactory.getLogger(QueueMetricsRefreshPool.class);
+
+ private static final int DEFAULT_THREAD_COUNT = 4;
+ public static final int JITTER_PERCENT = 10;
+
+ private static final AtomicReference<QueueMetricsRefreshPool> INSTANCE = new
AtomicReference<>(null);
+ private static final Object INIT_LOCK = new Object();
+
+ private final ScheduledExecutorService refreshPool;
+
+
+ /**
+ * Initializes the singleton pool with the specified thread count.
+ * Must be called during HiveServer2 startup. Subsequent calls are ignored.
+ *
+ * @param threadCount number of threads for the refresh pool
+ */
+ public static void init(int threadCount) {
+ if (INSTANCE.get() != null) {
+ LOG.debug("QueueMetricsRefreshPool already initialized, ignoring init
call");
+ return;
+ }
+ synchronized (INIT_LOCK) {
+ if (INSTANCE.get() == null) {
+ INSTANCE.set(new QueueMetricsRefreshPool(threadCount));
+ }
+ }
+ }
+
+ /**
+ * Returns the singleton instance. Must be called after {@link #init(int)}.
+ * For tests or non-HS2 environments, lazily initializes with default thread
count.
+ *
+ * @return the singleton pool instance
+ */
+ public static QueueMetricsRefreshPool getInstance() {
+ QueueMetricsRefreshPool local = INSTANCE.get();
+ if (local != null) {
+ return local;
+ }
+ // Lazy init for tests/non-HS2 with default thread count
+ synchronized (INIT_LOCK) {
+ local = INSTANCE.get();
+ if (local == null) {
+ LOG.warn("QueueMetricsRefreshPool not initialized via init(), using
default thread count: {}",
+ DEFAULT_THREAD_COUNT);
+ local = new QueueMetricsRefreshPool(DEFAULT_THREAD_COUNT);
+ INSTANCE.set(local);
+ }
+ return local;
+ }
+ }
+
+
+ private QueueMetricsRefreshPool(int threadCount) {
+ this.refreshPool = Executors.newScheduledThreadPool(threadCount,
+ new ThreadFactoryBuilder()
+ .setNameFormat("queue-metrics-refresh-%d")
+ .setDaemon(true)
+ .build());
+ LOG.info("QueueMetricsRefreshPool initialized with {} threads",
threadCount);
+ }
+
+
+ /**
+ * Schedules a periodic refresh task. initialDelay=0 so the first fetch runs
immediately.
+ */
+ public ScheduledFuture<Void> scheduleRefreshTask(Runnable task, long
intervalMs) {
+ return (ScheduledFuture<Void>) refreshPool.scheduleWithFixedDelay(task, 0,
intervalMs, TimeUnit.MILLISECONDS);
+ }
+
+ /**
+ * Calculates deterministic hash-based jitter for a queue name to prevent
thundering herd.
+ * Jitter range: 0 to (intervalMs * JITTER_PERCENT / 100)
+ *
+ * @param queueName the queue name to hash
+ * @param intervalMs the refresh interval in milliseconds
+ * @return jitter value in milliseconds (0 to intervalMs * 10%)
+ */
+ public static long calculateJitter(String queueName, long intervalMs) {
+ long jitterWindow = intervalMs * JITTER_PERCENT / 100;
+ return Math.abs(queueName.hashCode()) % jitterWindow;
+ }
Review Comment:
done
##########
ql/src/java/org/apache/hadoop/hive/ql/exec/tez/TezSessionState.java:
##########
@@ -797,6 +810,19 @@ public String getSessionId() {
protected final void setTezClient(TezClient session) {
this.session = session;
+
+ // Initialize YarnClient for queue metrics collection
+ if (session != null && yarnClient == null) {
+ try {
+ yarnClient = YarnClient.createYarnClient();
+ yarnClient.init(conf);
+ yarnClient.start();
+ LOG.info("YarnClient initialized for session: {}", sessionId);
+ } catch (Exception e) {
+ LOG.warn("Failed to initialize YarnClient for metrics collection", e);
+ yarnClient = null;
+ }
+ }
Review Comment:
done
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