Copilot commented on code in PR #16409:
URL: https://github.com/apache/pinot/pull/16409#discussion_r2396459193
##########
pinot-spi/src/main/java/org/apache/pinot/spi/executor/ThrottleOnCriticalHeapUsageExecutor.java:
##########
@@ -18,44 +18,537 @@
*/
package org.apache.pinot.spi.executor;
+import java.util.concurrent.BlockingQueue;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
import org.apache.pinot.spi.accounting.ThreadAccountant;
import org.apache.pinot.spi.exception.QueryErrorCode;
import org.apache.pinot.spi.query.QueryThreadContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
/**
- * An Executor that throttles task submission when the heap usage is critical.
+ * An Executor that queues tasks when the heap usage is critical instead of
rejecting them.
* Heap Usage level is obtained from {@link
ThreadAccountant#throttleQuerySubmission()}.
+ *
+ * Features:
+ * - Tasks are queued when heap usage is critical
+ * - Queued tasks are processed when heap usage drops below critical level
+ * - Configurable queue size and timeout (global default or per-task)
+ * - Background monitoring of heap usage to process queued tasks
*/
public class ThrottleOnCriticalHeapUsageExecutor extends
DecoratorExecutorService {
+ private static final Logger LOGGER =
LoggerFactory.getLogger(ThrottleOnCriticalHeapUsageExecutor.class);
+
+ // Default configuration values
+ // Defaults are kept near config in CommonConstants; no local defaults
needed here
+ private static final long LOG_THROTTLE_INTERVAL_MS = 30000; // Log queue
status every 30 seconds
+
+ public enum Mode {
+ QUEUE,
+ REJECT
+ }
+
+ private final BlockingQueue<QueuedTask> _taskQueue;
+ private final int _maxQueueSize;
+ private final long _defaultQueueTimeoutMs;
+ private final ScheduledExecutorService _monitorExecutor;
+ private final AtomicBoolean _isShutdown = new AtomicBoolean(false);
+ private final AtomicInteger _queuedTaskCount = new AtomicInteger(0);
+ private final AtomicInteger _processedTaskCount = new AtomicInteger(0);
+ private final AtomicInteger _timedOutTaskCount = new AtomicInteger(0);
+ private final AtomicInteger _shutdownCanceledTaskCount = new
AtomicInteger(0);
+ private volatile long _lastQueueStatusLogTime = 0;
+ private final Mode _mode;
Review Comment:
The constructor is missing the original backward-compatible constructor that
takes only `ExecutorService`. This breaks backward compatibility as mentioned
in the PR description. Consider adding the original constructor that delegates
to this new one with default values.
```suggestion
/**
* Backward-compatible constructor that takes only ExecutorService.
* Uses default values for queue size, timeout, monitor interval, and mode.
*/
public ThrottleOnCriticalHeapUsageExecutor(ExecutorService
executorService) {
this(executorService,
1000, // default maxQueueSize
10000L, // default defaultQueueTimeoutMs
1000L, // default monitorIntervalMs
Mode.QUEUE); // default mode
}
```
##########
pinot-spi/src/main/java/org/apache/pinot/spi/executor/ThrottleOnCriticalHeapUsageExecutor.java:
##########
@@ -18,44 +18,537 @@
*/
package org.apache.pinot.spi.executor;
+import java.util.concurrent.BlockingQueue;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
import org.apache.pinot.spi.accounting.ThreadAccountant;
import org.apache.pinot.spi.exception.QueryErrorCode;
import org.apache.pinot.spi.query.QueryThreadContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
/**
- * An Executor that throttles task submission when the heap usage is critical.
+ * An Executor that queues tasks when the heap usage is critical instead of
rejecting them.
* Heap Usage level is obtained from {@link
ThreadAccountant#throttleQuerySubmission()}.
+ *
+ * Features:
+ * - Tasks are queued when heap usage is critical
+ * - Queued tasks are processed when heap usage drops below critical level
+ * - Configurable queue size and timeout (global default or per-task)
+ * - Background monitoring of heap usage to process queued tasks
*/
public class ThrottleOnCriticalHeapUsageExecutor extends
DecoratorExecutorService {
+ private static final Logger LOGGER =
LoggerFactory.getLogger(ThrottleOnCriticalHeapUsageExecutor.class);
+
+ // Default configuration values
+ // Defaults are kept near config in CommonConstants; no local defaults
needed here
+ private static final long LOG_THROTTLE_INTERVAL_MS = 30000; // Log queue
status every 30 seconds
+
+ public enum Mode {
+ QUEUE,
+ REJECT
+ }
+
+ private final BlockingQueue<QueuedTask> _taskQueue;
+ private final int _maxQueueSize;
+ private final long _defaultQueueTimeoutMs;
+ private final ScheduledExecutorService _monitorExecutor;
+ private final AtomicBoolean _isShutdown = new AtomicBoolean(false);
+ private final AtomicInteger _queuedTaskCount = new AtomicInteger(0);
+ private final AtomicInteger _processedTaskCount = new AtomicInteger(0);
+ private final AtomicInteger _timedOutTaskCount = new AtomicInteger(0);
+ private final AtomicInteger _shutdownCanceledTaskCount = new
AtomicInteger(0);
+ private volatile long _lastQueueStatusLogTime = 0;
+ private final Mode _mode;
- public ThrottleOnCriticalHeapUsageExecutor(ExecutorService executorService) {
+ public ThrottleOnCriticalHeapUsageExecutor(ExecutorService executorService,
+ int maxQueueSize, long defaultQueueTimeoutMs, long monitorIntervalMs,
Mode mode) {
super(executorService);
+ _maxQueueSize = maxQueueSize;
+ _defaultQueueTimeoutMs = defaultQueueTimeoutMs;
+ _taskQueue = new LinkedBlockingQueue<>(maxQueueSize);
+ _mode = mode;
+
+ // Create a single-threaded scheduler for monitoring heap usage
+ _monitorExecutor = Executors.newSingleThreadScheduledExecutor(r -> {
+ Thread t = new Thread(r, "throttle-heap-monitor");
+ t.setDaemon(true);
+ return t;
+ });
+
+ // Start the monitoring task
+ _monitorExecutor.scheduleWithFixedDelay(this::processQueuedTasks,
+ monitorIntervalMs, monitorIntervalMs, TimeUnit.MILLISECONDS);
+
+ LOGGER.info(
+ "ThrottleOnCriticalHeapUsageExecutor initialized with queue size: {},
default timeout: {}ms, "
+ + "monitor interval: {}ms, mode: {}", maxQueueSize,
defaultQueueTimeoutMs, monitorIntervalMs, mode);
+ }
+
+ /**
+ * Check if a task should be queued due to critical heap usage
+ * @return true if the task should be queued, false if it can be executed
immediately
+ */
+ protected boolean shouldQueueTask() {
+ return QueryThreadContext.get().getAccountant().throttleQuerySubmission();
}
- protected void checkTaskAllowed() {
- if (QueryThreadContext.get().getAccountant().throttleQuerySubmission()) {
- throw QueryErrorCode.SERVER_RESOURCE_LIMIT_EXCEEDED.asException("Tasks
throttled due to high heap usage.");
+ /**
+ * Process queued tasks when heap usage is below critical level
+ */
+ private void processQueuedTasks() {
+ if (_isShutdown.get()) {
+ return;
+ }
+
+ try {
+ int initialQueueSize = _taskQueue.size();
+ long currentTime = System.currentTimeMillis();
+
+ // Log queue size for monitoring if there are queued tasks (throttled to
prevent log flooding)
+ if (initialQueueSize > 0 && (currentTime - _lastQueueStatusLogTime) >
LOG_THROTTLE_INTERVAL_MS) {
+ LOGGER.info("Processing queued tasks. Current queue size: {}, Queued:
{}, Processed: {}, "
+ + "Timed out: {}, Shutdown canceled: {}",
+ initialQueueSize, _queuedTaskCount.get(),
_processedTaskCount.get(),
+ _timedOutTaskCount.get(), _shutdownCanceledTaskCount.get());
+ _lastQueueStatusLogTime = currentTime;
+ // Metrics intentionally not set here
+ }
+
+ // Process tasks while heap usage is not critical and queue is not empty
+ while (!shouldQueueTask() && !_taskQueue.isEmpty()) {
+ QueuedTask queuedTask = _taskQueue.poll();
+ if (queuedTask != null) {
+ long queueTime = System.currentTimeMillis() -
queuedTask.getQueueTime();
+
+ if (queueTime > queuedTask.getTimeoutMs()) {
+ // Task has timed out in queue
+ queuedTask.timeout();
+ _timedOutTaskCount.incrementAndGet();
+ LOGGER.warn("Task timed out after {}ms in queue (timeout: {}ms)",
queueTime, queuedTask.getTimeoutMs());
+ } else {
+ // Submit the task for execution
+ try {
+ queuedTask.execute();
+ _processedTaskCount.incrementAndGet();
+ LOGGER.debug("Processed queued task after {}ms in queue",
queueTime);
+ } catch (Exception e) {
+ LOGGER.error("Error executing queued task", e);
+ queuedTask.fail(e);
+ }
+ }
+ }
+ }
+
+ // Log completion only for significant processing (5+ tasks) to avoid
log spam
+ int finalQueueSize = _taskQueue.size();
+ if (initialQueueSize > 0 && initialQueueSize != finalQueueSize) {
+ int processedThisCycle = initialQueueSize - finalQueueSize;
+ if (processedThisCycle >= 5) {
+ LOGGER.info("Completed processing cycle. Processed {} tasks,
remaining queue size: {}",
+ processedThisCycle, finalQueueSize);
+ } else {
+ LOGGER.debug("Completed processing cycle. Processed {} tasks,
remaining queue size: {}",
+ processedThisCycle, finalQueueSize);
+ }
+ }
+ } catch (Exception e) {
+ LOGGER.error("Error in processQueuedTasks", e);
}
}
@Override
protected <T> Callable<T> decorate(Callable<T> task) {
- checkTaskAllowed();
return () -> {
- checkTaskAllowed();
- return task.call();
+ if (shouldQueueTask()) {
+ if (_mode == Mode.REJECT) {
+ throw QueryErrorCode.SERVER_RESOURCE_LIMIT_EXCEEDED.asException(
+ "Heap usage critical; rejecting task per configuration.");
+ }
+ // Queue the task if heap usage is critical
+ long timeoutMs = computePerTaskTimeoutMs(_defaultQueueTimeoutMs);
+ return queueCallableTask(task, timeoutMs);
+ } else {
+ // Execute immediately if heap usage is normal
+ return task.call();
+ }
};
}
@Override
protected Runnable decorate(Runnable task) {
- checkTaskAllowed();
return () -> {
- checkTaskAllowed();
- task.run();
+ if (shouldQueueTask()) {
+ if (_mode == Mode.REJECT) {
+ throw QueryErrorCode.SERVER_RESOURCE_LIMIT_EXCEEDED.asException(
+ "Heap usage critical; rejecting task per configuration.");
+ }
+ // Queue the task if heap usage is critical
+ long timeoutMs = computePerTaskTimeoutMs(_defaultQueueTimeoutMs);
+ queueRunnableTask(task, timeoutMs);
+ } else {
+ // Execute immediately if heap usage is normal
+ task.run();
+ }
};
}
+
+ private long computePerTaskTimeoutMs(long configuredTimeoutMs) {
+ try {
+ if (QueryThreadContext.get() != null &&
QueryThreadContext.get().getExecutionContext() != null) {
+ long remaining =
QueryThreadContext.getIfAvailable().getExecutionContext().getPassiveDeadlineMs()
Review Comment:
Inconsistent use of `QueryThreadContext.get()` and
`QueryThreadContext.getIfAvailable()` within the same method. Line 205 calls
`get()` twice but line 206 calls `getIfAvailable()`. This could lead to
different thread contexts being accessed or null pointer exceptions if the
context becomes unavailable between calls.
```suggestion
QueryThreadContext context = QueryThreadContext.getIfAvailable();
if (context != null && context.getExecutionContext() != null) {
long remaining = context.getExecutionContext().getPassiveDeadlineMs()
```
##########
pinot-spi/src/main/java/org/apache/pinot/spi/executor/ThrottleOnCriticalHeapUsageExecutor.java:
##########
@@ -18,44 +18,537 @@
*/
package org.apache.pinot.spi.executor;
+import java.util.concurrent.BlockingQueue;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
import org.apache.pinot.spi.accounting.ThreadAccountant;
import org.apache.pinot.spi.exception.QueryErrorCode;
import org.apache.pinot.spi.query.QueryThreadContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
/**
- * An Executor that throttles task submission when the heap usage is critical.
+ * An Executor that queues tasks when the heap usage is critical instead of
rejecting them.
* Heap Usage level is obtained from {@link
ThreadAccountant#throttleQuerySubmission()}.
+ *
+ * Features:
+ * - Tasks are queued when heap usage is critical
+ * - Queued tasks are processed when heap usage drops below critical level
+ * - Configurable queue size and timeout (global default or per-task)
+ * - Background monitoring of heap usage to process queued tasks
*/
public class ThrottleOnCriticalHeapUsageExecutor extends
DecoratorExecutorService {
+ private static final Logger LOGGER =
LoggerFactory.getLogger(ThrottleOnCriticalHeapUsageExecutor.class);
+
+ // Default configuration values
+ // Defaults are kept near config in CommonConstants; no local defaults
needed here
+ private static final long LOG_THROTTLE_INTERVAL_MS = 30000; // Log queue
status every 30 seconds
+
+ public enum Mode {
+ QUEUE,
+ REJECT
+ }
+
+ private final BlockingQueue<QueuedTask> _taskQueue;
+ private final int _maxQueueSize;
+ private final long _defaultQueueTimeoutMs;
+ private final ScheduledExecutorService _monitorExecutor;
+ private final AtomicBoolean _isShutdown = new AtomicBoolean(false);
+ private final AtomicInteger _queuedTaskCount = new AtomicInteger(0);
+ private final AtomicInteger _processedTaskCount = new AtomicInteger(0);
+ private final AtomicInteger _timedOutTaskCount = new AtomicInteger(0);
+ private final AtomicInteger _shutdownCanceledTaskCount = new
AtomicInteger(0);
+ private volatile long _lastQueueStatusLogTime = 0;
+ private final Mode _mode;
- public ThrottleOnCriticalHeapUsageExecutor(ExecutorService executorService) {
+ public ThrottleOnCriticalHeapUsageExecutor(ExecutorService executorService,
+ int maxQueueSize, long defaultQueueTimeoutMs, long monitorIntervalMs,
Mode mode) {
super(executorService);
+ _maxQueueSize = maxQueueSize;
+ _defaultQueueTimeoutMs = defaultQueueTimeoutMs;
+ _taskQueue = new LinkedBlockingQueue<>(maxQueueSize);
+ _mode = mode;
+
+ // Create a single-threaded scheduler for monitoring heap usage
+ _monitorExecutor = Executors.newSingleThreadScheduledExecutor(r -> {
+ Thread t = new Thread(r, "throttle-heap-monitor");
+ t.setDaemon(true);
+ return t;
+ });
+
+ // Start the monitoring task
+ _monitorExecutor.scheduleWithFixedDelay(this::processQueuedTasks,
+ monitorIntervalMs, monitorIntervalMs, TimeUnit.MILLISECONDS);
+
+ LOGGER.info(
+ "ThrottleOnCriticalHeapUsageExecutor initialized with queue size: {},
default timeout: {}ms, "
+ + "monitor interval: {}ms, mode: {}", maxQueueSize,
defaultQueueTimeoutMs, monitorIntervalMs, mode);
+ }
+
+ /**
+ * Check if a task should be queued due to critical heap usage
+ * @return true if the task should be queued, false if it can be executed
immediately
+ */
+ protected boolean shouldQueueTask() {
+ return QueryThreadContext.get().getAccountant().throttleQuerySubmission();
}
- protected void checkTaskAllowed() {
- if (QueryThreadContext.get().getAccountant().throttleQuerySubmission()) {
- throw QueryErrorCode.SERVER_RESOURCE_LIMIT_EXCEEDED.asException("Tasks
throttled due to high heap usage.");
+ /**
+ * Process queued tasks when heap usage is below critical level
+ */
+ private void processQueuedTasks() {
+ if (_isShutdown.get()) {
+ return;
+ }
+
+ try {
+ int initialQueueSize = _taskQueue.size();
+ long currentTime = System.currentTimeMillis();
+
+ // Log queue size for monitoring if there are queued tasks (throttled to
prevent log flooding)
+ if (initialQueueSize > 0 && (currentTime - _lastQueueStatusLogTime) >
LOG_THROTTLE_INTERVAL_MS) {
+ LOGGER.info("Processing queued tasks. Current queue size: {}, Queued:
{}, Processed: {}, "
+ + "Timed out: {}, Shutdown canceled: {}",
+ initialQueueSize, _queuedTaskCount.get(),
_processedTaskCount.get(),
+ _timedOutTaskCount.get(), _shutdownCanceledTaskCount.get());
+ _lastQueueStatusLogTime = currentTime;
+ // Metrics intentionally not set here
+ }
+
+ // Process tasks while heap usage is not critical and queue is not empty
+ while (!shouldQueueTask() && !_taskQueue.isEmpty()) {
+ QueuedTask queuedTask = _taskQueue.poll();
+ if (queuedTask != null) {
+ long queueTime = System.currentTimeMillis() -
queuedTask.getQueueTime();
+
+ if (queueTime > queuedTask.getTimeoutMs()) {
+ // Task has timed out in queue
+ queuedTask.timeout();
+ _timedOutTaskCount.incrementAndGet();
+ LOGGER.warn("Task timed out after {}ms in queue (timeout: {}ms)",
queueTime, queuedTask.getTimeoutMs());
+ } else {
+ // Submit the task for execution
+ try {
+ queuedTask.execute();
+ _processedTaskCount.incrementAndGet();
+ LOGGER.debug("Processed queued task after {}ms in queue",
queueTime);
+ } catch (Exception e) {
+ LOGGER.error("Error executing queued task", e);
+ queuedTask.fail(e);
+ }
+ }
+ }
+ }
+
+ // Log completion only for significant processing (5+ tasks) to avoid
log spam
+ int finalQueueSize = _taskQueue.size();
+ if (initialQueueSize > 0 && initialQueueSize != finalQueueSize) {
+ int processedThisCycle = initialQueueSize - finalQueueSize;
+ if (processedThisCycle >= 5) {
+ LOGGER.info("Completed processing cycle. Processed {} tasks,
remaining queue size: {}",
+ processedThisCycle, finalQueueSize);
+ } else {
+ LOGGER.debug("Completed processing cycle. Processed {} tasks,
remaining queue size: {}",
+ processedThisCycle, finalQueueSize);
+ }
+ }
+ } catch (Exception e) {
+ LOGGER.error("Error in processQueuedTasks", e);
}
}
@Override
protected <T> Callable<T> decorate(Callable<T> task) {
- checkTaskAllowed();
return () -> {
- checkTaskAllowed();
- return task.call();
+ if (shouldQueueTask()) {
+ if (_mode == Mode.REJECT) {
+ throw QueryErrorCode.SERVER_RESOURCE_LIMIT_EXCEEDED.asException(
+ "Heap usage critical; rejecting task per configuration.");
+ }
+ // Queue the task if heap usage is critical
+ long timeoutMs = computePerTaskTimeoutMs(_defaultQueueTimeoutMs);
+ return queueCallableTask(task, timeoutMs);
+ } else {
+ // Execute immediately if heap usage is normal
+ return task.call();
+ }
};
}
@Override
protected Runnable decorate(Runnable task) {
- checkTaskAllowed();
return () -> {
- checkTaskAllowed();
- task.run();
+ if (shouldQueueTask()) {
+ if (_mode == Mode.REJECT) {
+ throw QueryErrorCode.SERVER_RESOURCE_LIMIT_EXCEEDED.asException(
+ "Heap usage critical; rejecting task per configuration.");
+ }
+ // Queue the task if heap usage is critical
+ long timeoutMs = computePerTaskTimeoutMs(_defaultQueueTimeoutMs);
+ queueRunnableTask(task, timeoutMs);
+ } else {
+ // Execute immediately if heap usage is normal
+ task.run();
+ }
};
}
+
+ private long computePerTaskTimeoutMs(long configuredTimeoutMs) {
+ try {
+ if (QueryThreadContext.get() != null &&
QueryThreadContext.get().getExecutionContext() != null) {
+ long remaining =
QueryThreadContext.getIfAvailable().getExecutionContext().getPassiveDeadlineMs()
+ - System.currentTimeMillis();
+ if (remaining <= 0) {
+ return 0L;
+ }
+ // Do not wait in queue longer than the query's remaining passive
deadline
+ return Math.min(configuredTimeoutMs, remaining);
+ }
+ } catch (Throwable t) {
+ // Be conservative and use configured timeout if context is not available
+ LOGGER.debug("Failed to compute per-task timeout from thread context;
using configured timeout.", t);
+ }
+ return configuredTimeoutMs;
+ }
+
+ /**
+ * Queue a callable task and wait for its execution
+ */
+ private <T> T queueCallableTask(Callable<T> task, long timeoutMs)
+ throws Exception {
+ QueuedCallableTask<T> queuedTask = new QueuedCallableTask<>(task,
timeoutMs);
+
+ if (!_taskQueue.offer(queuedTask)) {
+ // Queue is full
+ throw QueryErrorCode.SERVER_RESOURCE_LIMIT_EXCEEDED.asException(
+ "Task queue is full (size: " + _maxQueueSize + ") due to high heap
usage.");
+ }
+
+ _queuedTaskCount.incrementAndGet();
+ LOGGER.debug("Queued callable task, queue size: {}", _taskQueue.size());
+ // Metrics intentionally not set here
+
+ // Wait for the task to complete or timeout
+ return queuedTask.get(timeoutMs, TimeUnit.MILLISECONDS);
+ }
+
+ /**
+ * Queue a runnable task and wait for its execution
+ */
+ private void queueRunnableTask(Runnable task, long timeoutMs) {
+ QueuedRunnableTask queuedTask = new QueuedRunnableTask(task, timeoutMs);
+
+ if (!_taskQueue.offer(queuedTask)) {
+ // Queue is full
+ throw QueryErrorCode.SERVER_RESOURCE_LIMIT_EXCEEDED.asException(
+ "Task queue is full (size: " + _maxQueueSize + ") due to high heap
usage.");
+ }
+
+ _queuedTaskCount.incrementAndGet();
+ LOGGER.debug("Queued runnable task, queue size: {}", _taskQueue.size());
+ // Metrics intentionally not set here
+
+ try {
+ // Wait for the task to complete or timeout
+ queuedTask.get(timeoutMs, TimeUnit.MILLISECONDS);
+ } catch (Exception e) {
+ if (e.getCause() instanceof RuntimeException) {
+ throw (RuntimeException) e.getCause();
+ } else {
+ throw new RuntimeException("Error executing queued task", e);
+ }
+ }
+ }
+
+ @Override
+ public void shutdown() {
+ _isShutdown.set(true);
+ _monitorExecutor.shutdownNow();
+
+ // Allow the monitor thread to complete current processing
+ try {
+ if (!_monitorExecutor.awaitTermination(30, TimeUnit.SECONDS)) {
+ LOGGER.warn("Monitor executor did not terminate within the timeout
period.");
+ }
+ } catch (InterruptedException e) {
+ LOGGER.warn("Interrupted while waiting for monitor executor to
terminate.", e);
+ Thread.currentThread().interrupt();
+ }
+
+ // Cancel remaining tasks in the queue - fail them with shutdown exception
+ int remainingTasks = 0; // keep local counter for logging
+ while (!_taskQueue.isEmpty()) {
+ QueuedTask task = _taskQueue.poll();
+ if (task != null) {
+ remainingTasks++;
+ task.fail(new IllegalStateException("Executor is shutting down"));
+ _shutdownCanceledTaskCount.incrementAndGet();
+ // Metrics intentionally not set here
+ }
+ }
+
+ super.shutdown();
+
+ LOGGER.info("ThrottleOnCriticalHeapUsageExecutor shutdown. Stats - Queued:
{}, Processed: {}, "
+ + "Timed out: {}, Shutdown canceled: {}, Remaining: {}",
+ _queuedTaskCount.get(), _processedTaskCount.get(),
_timedOutTaskCount.get(),
+ _shutdownCanceledTaskCount.get(), remainingTasks);
+ }
+
+ /**
+ * Get current queue size
+ */
+ public int getQueueSize() {
+ return _taskQueue.size();
+ }
+
+ /**
+ * Get total number of tasks queued
+ */
+ public int getQueuedTaskCount() {
+ return _queuedTaskCount.get();
+ }
+
+ /**
+ * Get total number of tasks processed from queue
+ */
+ public int getProcessedTaskCount() {
+ return _processedTaskCount.get();
+ }
+
+ /**
+ * Get total number of tasks that timed out in queue
+ */
+ public int getTimedOutTaskCount() {
+ return _timedOutTaskCount.get();
+ }
+
+ /**
+ * Get total number of tasks canceled during shutdown
+ */
+ public int getShutdownCanceledTaskCount() {
+ return _shutdownCanceledTaskCount.get();
+ }
+
+ /**
+ * Base class for queued tasks.
+ *
+ * <p>The {@code QueuedTask} class represents a task that can be queued for
execution when the system is under
+ * critical heap usage. It provides a common interface for handling task
execution, timeouts, and failures.</p>
+ *
+ * <p>Lifecycle:
+ * <ul>
+ * <li>Tasks are created and added to the queue when heap usage is
critical.</li>
+ * <li>When heap usage drops below the critical level, tasks are dequeued
and executed.</li>
+ * <li>If a task remains in the queue beyond a configured timeout, the
{@code timeout()} method is invoked.</li>
+ * <li>If an exception occurs during execution, the {@code fail(Exception
e)} method is invoked.</li>
+ * </ul>
+ * </p>
+ *
+ * <p>Thread-safety:
+ * <ul>
+ * <li>Instances of {@code QueuedTask} are not inherently thread-safe and
should be accessed in a thread-safe
+ * manner by the enclosing executor.</li>
+ * <li>The enclosing {@code ThrottleOnCriticalHeapUsageExecutor} ensures
proper synchronization when accessing
+ * and modifying the queue.</li>
+ * </ul>
+ * </p>
+ */
+ private abstract static class QueuedTask {
+ private final long _queueTime;
+ private final long _timeoutMs;
+
+ protected QueuedTask(long timeoutMs) {
+ _queueTime = System.currentTimeMillis();
+ _timeoutMs = timeoutMs;
+ }
+
+ public long getQueueTime() {
+ return _queueTime;
+ }
+
+ public long getTimeoutMs() {
+ return _timeoutMs;
+ }
+
+ public abstract void execute()
+ throws Exception;
+
+ public abstract void timeout();
+
+ public abstract void fail(Exception e);
+ }
+
+ /**
+ * Wrapper for callable tasks that can be queued
+ */
+ private class QueuedCallableTask<T> extends QueuedTask {
+ private final Callable<T> _task;
+ private volatile T _result;
+ private volatile Exception _exception;
+ private volatile boolean _completed = false;
+ private final Object _lock = new Object();
+
+ public QueuedCallableTask(Callable<T> task, long timeoutMs) {
+ super(timeoutMs);
+ _task = task;
+ }
+
+ @Override
+ public void execute()
+ throws Exception {
+ try {
+ T result = _task.call();
+ synchronized (_lock) {
+ _result = result;
+ _completed = true;
+ _lock.notifyAll();
+ }
+ } catch (Exception e) {
+ fail(e);
+ throw e;
Review Comment:
[nitpick] The exception is handled by calling `fail(e)` and then re-thrown.
This pattern is repeated in both `QueuedCallableTask` and `QueuedRunnableTask`.
The re-throwing seems unnecessary since `fail(e)` already sets the exception
state for waiting threads.
```suggestion
```
##########
pinot-query-runtime/src/main/java/org/apache/pinot/query/runtime/QueryRunner.java:
##########
@@ -219,8 +219,27 @@ public void init(PinotConfiguration serverConf,
InstanceDataManager instanceData
if
(serverConf.getProperty(Server.CONFIG_OF_ENABLE_QUERY_SCHEDULER_THROTTLING_ON_HEAP_USAGE,
Server.DEFAULT_ENABLE_QUERY_SCHEDULER_THROTTLING_ON_HEAP_USAGE)) {
- LOGGER.info("Enable OOM Throttling on critical heap usage for
multi-stage executor");
- _executorService = new
ThrottleOnCriticalHeapUsageExecutor(_executorService);
+ String modeStr =
serverConf.getProperty(Server.CONFIG_OF_OOM_THROTTLE_MODE,
Server.DEFAULT_OOM_THROTTLE_MODE);
+ ThrottleOnCriticalHeapUsageExecutor.Mode mode;
+ try {
+ mode =
ThrottleOnCriticalHeapUsageExecutor.Mode.valueOf(modeStr.toUpperCase());
+ } catch (IllegalArgumentException e) {
+ LOGGER.warn("Invalid oomThrottle.mode: {}. Falling back to default:
{}", modeStr,
+ Server.DEFAULT_OOM_THROTTLE_MODE);
+ mode =
ThrottleOnCriticalHeapUsageExecutor.Mode.valueOf(Server.DEFAULT_OOM_THROTTLE_MODE.toUpperCase());
+ }
Review Comment:
The exception handling logic is duplicated in both QueryRunner.java and
ResourceManager.java. Consider extracting this mode parsing logic into a
utility method to avoid code duplication and ensure consistent error handling.
```suggestion
mode = ExecutorServiceUtils.parseEnumWithDefault(
ThrottleOnCriticalHeapUsageExecutor.Mode.class,
modeStr,
Server.DEFAULT_OOM_THROTTLE_MODE,
LOGGER,
"oomThrottle.mode"
);
```
##########
pinot-spi/src/main/java/org/apache/pinot/spi/executor/ThrottleOnCriticalHeapUsageExecutor.java:
##########
@@ -18,44 +18,537 @@
*/
package org.apache.pinot.spi.executor;
+import java.util.concurrent.BlockingQueue;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
import org.apache.pinot.spi.accounting.ThreadAccountant;
import org.apache.pinot.spi.exception.QueryErrorCode;
import org.apache.pinot.spi.query.QueryThreadContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
/**
- * An Executor that throttles task submission when the heap usage is critical.
+ * An Executor that queues tasks when the heap usage is critical instead of
rejecting them.
* Heap Usage level is obtained from {@link
ThreadAccountant#throttleQuerySubmission()}.
+ *
+ * Features:
+ * - Tasks are queued when heap usage is critical
+ * - Queued tasks are processed when heap usage drops below critical level
+ * - Configurable queue size and timeout (global default or per-task)
+ * - Background monitoring of heap usage to process queued tasks
*/
public class ThrottleOnCriticalHeapUsageExecutor extends
DecoratorExecutorService {
+ private static final Logger LOGGER =
LoggerFactory.getLogger(ThrottleOnCriticalHeapUsageExecutor.class);
+
+ // Default configuration values
+ // Defaults are kept near config in CommonConstants; no local defaults
needed here
+ private static final long LOG_THROTTLE_INTERVAL_MS = 30000; // Log queue
status every 30 seconds
+
+ public enum Mode {
+ QUEUE,
+ REJECT
+ }
+
+ private final BlockingQueue<QueuedTask> _taskQueue;
+ private final int _maxQueueSize;
+ private final long _defaultQueueTimeoutMs;
+ private final ScheduledExecutorService _monitorExecutor;
+ private final AtomicBoolean _isShutdown = new AtomicBoolean(false);
+ private final AtomicInteger _queuedTaskCount = new AtomicInteger(0);
+ private final AtomicInteger _processedTaskCount = new AtomicInteger(0);
+ private final AtomicInteger _timedOutTaskCount = new AtomicInteger(0);
+ private final AtomicInteger _shutdownCanceledTaskCount = new
AtomicInteger(0);
+ private volatile long _lastQueueStatusLogTime = 0;
+ private final Mode _mode;
- public ThrottleOnCriticalHeapUsageExecutor(ExecutorService executorService) {
+ public ThrottleOnCriticalHeapUsageExecutor(ExecutorService executorService,
+ int maxQueueSize, long defaultQueueTimeoutMs, long monitorIntervalMs,
Mode mode) {
super(executorService);
+ _maxQueueSize = maxQueueSize;
+ _defaultQueueTimeoutMs = defaultQueueTimeoutMs;
+ _taskQueue = new LinkedBlockingQueue<>(maxQueueSize);
+ _mode = mode;
+
+ // Create a single-threaded scheduler for monitoring heap usage
+ _monitorExecutor = Executors.newSingleThreadScheduledExecutor(r -> {
+ Thread t = new Thread(r, "throttle-heap-monitor");
+ t.setDaemon(true);
+ return t;
+ });
+
+ // Start the monitoring task
+ _monitorExecutor.scheduleWithFixedDelay(this::processQueuedTasks,
+ monitorIntervalMs, monitorIntervalMs, TimeUnit.MILLISECONDS);
+
+ LOGGER.info(
+ "ThrottleOnCriticalHeapUsageExecutor initialized with queue size: {},
default timeout: {}ms, "
+ + "monitor interval: {}ms, mode: {}", maxQueueSize,
defaultQueueTimeoutMs, monitorIntervalMs, mode);
+ }
+
+ /**
+ * Check if a task should be queued due to critical heap usage
+ * @return true if the task should be queued, false if it can be executed
immediately
+ */
+ protected boolean shouldQueueTask() {
+ return QueryThreadContext.get().getAccountant().throttleQuerySubmission();
}
- protected void checkTaskAllowed() {
- if (QueryThreadContext.get().getAccountant().throttleQuerySubmission()) {
- throw QueryErrorCode.SERVER_RESOURCE_LIMIT_EXCEEDED.asException("Tasks
throttled due to high heap usage.");
+ /**
+ * Process queued tasks when heap usage is below critical level
+ */
+ private void processQueuedTasks() {
+ if (_isShutdown.get()) {
+ return;
+ }
+
+ try {
+ int initialQueueSize = _taskQueue.size();
+ long currentTime = System.currentTimeMillis();
+
+ // Log queue size for monitoring if there are queued tasks (throttled to
prevent log flooding)
+ if (initialQueueSize > 0 && (currentTime - _lastQueueStatusLogTime) >
LOG_THROTTLE_INTERVAL_MS) {
+ LOGGER.info("Processing queued tasks. Current queue size: {}, Queued:
{}, Processed: {}, "
+ + "Timed out: {}, Shutdown canceled: {}",
+ initialQueueSize, _queuedTaskCount.get(),
_processedTaskCount.get(),
+ _timedOutTaskCount.get(), _shutdownCanceledTaskCount.get());
+ _lastQueueStatusLogTime = currentTime;
+ // Metrics intentionally not set here
+ }
+
+ // Process tasks while heap usage is not critical and queue is not empty
+ while (!shouldQueueTask() && !_taskQueue.isEmpty()) {
+ QueuedTask queuedTask = _taskQueue.poll();
+ if (queuedTask != null) {
+ long queueTime = System.currentTimeMillis() -
queuedTask.getQueueTime();
+
+ if (queueTime > queuedTask.getTimeoutMs()) {
+ // Task has timed out in queue
+ queuedTask.timeout();
+ _timedOutTaskCount.incrementAndGet();
+ LOGGER.warn("Task timed out after {}ms in queue (timeout: {}ms)",
queueTime, queuedTask.getTimeoutMs());
+ } else {
+ // Submit the task for execution
+ try {
+ queuedTask.execute();
+ _processedTaskCount.incrementAndGet();
+ LOGGER.debug("Processed queued task after {}ms in queue",
queueTime);
+ } catch (Exception e) {
+ LOGGER.error("Error executing queued task", e);
+ queuedTask.fail(e);
+ }
+ }
+ }
+ }
+
+ // Log completion only for significant processing (5+ tasks) to avoid
log spam
+ int finalQueueSize = _taskQueue.size();
+ if (initialQueueSize > 0 && initialQueueSize != finalQueueSize) {
+ int processedThisCycle = initialQueueSize - finalQueueSize;
+ if (processedThisCycle >= 5) {
+ LOGGER.info("Completed processing cycle. Processed {} tasks,
remaining queue size: {}",
+ processedThisCycle, finalQueueSize);
+ } else {
+ LOGGER.debug("Completed processing cycle. Processed {} tasks,
remaining queue size: {}",
+ processedThisCycle, finalQueueSize);
+ }
+ }
+ } catch (Exception e) {
+ LOGGER.error("Error in processQueuedTasks", e);
}
}
@Override
protected <T> Callable<T> decorate(Callable<T> task) {
- checkTaskAllowed();
return () -> {
- checkTaskAllowed();
- return task.call();
+ if (shouldQueueTask()) {
+ if (_mode == Mode.REJECT) {
+ throw QueryErrorCode.SERVER_RESOURCE_LIMIT_EXCEEDED.asException(
+ "Heap usage critical; rejecting task per configuration.");
+ }
+ // Queue the task if heap usage is critical
+ long timeoutMs = computePerTaskTimeoutMs(_defaultQueueTimeoutMs);
+ return queueCallableTask(task, timeoutMs);
+ } else {
+ // Execute immediately if heap usage is normal
+ return task.call();
+ }
};
}
@Override
protected Runnable decorate(Runnable task) {
- checkTaskAllowed();
return () -> {
- checkTaskAllowed();
- task.run();
+ if (shouldQueueTask()) {
+ if (_mode == Mode.REJECT) {
+ throw QueryErrorCode.SERVER_RESOURCE_LIMIT_EXCEEDED.asException(
+ "Heap usage critical; rejecting task per configuration.");
+ }
+ // Queue the task if heap usage is critical
+ long timeoutMs = computePerTaskTimeoutMs(_defaultQueueTimeoutMs);
+ queueRunnableTask(task, timeoutMs);
+ } else {
+ // Execute immediately if heap usage is normal
+ task.run();
+ }
};
}
+
+ private long computePerTaskTimeoutMs(long configuredTimeoutMs) {
+ try {
+ if (QueryThreadContext.get() != null &&
QueryThreadContext.get().getExecutionContext() != null) {
+ long remaining =
QueryThreadContext.getIfAvailable().getExecutionContext().getPassiveDeadlineMs()
+ - System.currentTimeMillis();
+ if (remaining <= 0) {
+ return 0L;
+ }
+ // Do not wait in queue longer than the query's remaining passive
deadline
+ return Math.min(configuredTimeoutMs, remaining);
+ }
+ } catch (Throwable t) {
+ // Be conservative and use configured timeout if context is not available
+ LOGGER.debug("Failed to compute per-task timeout from thread context;
using configured timeout.", t);
+ }
+ return configuredTimeoutMs;
+ }
+
+ /**
+ * Queue a callable task and wait for its execution
+ */
+ private <T> T queueCallableTask(Callable<T> task, long timeoutMs)
+ throws Exception {
+ QueuedCallableTask<T> queuedTask = new QueuedCallableTask<>(task,
timeoutMs);
+
+ if (!_taskQueue.offer(queuedTask)) {
+ // Queue is full
+ throw QueryErrorCode.SERVER_RESOURCE_LIMIT_EXCEEDED.asException(
+ "Task queue is full (size: " + _maxQueueSize + ") due to high heap
usage.");
+ }
+
+ _queuedTaskCount.incrementAndGet();
+ LOGGER.debug("Queued callable task, queue size: {}", _taskQueue.size());
+ // Metrics intentionally not set here
Review Comment:
The comment 'Metrics intentionally not set here' appears multiple times but
doesn't explain why metrics are not set. Since ServerGauge metrics were added
for this functionality, it would be helpful to explain the reasoning or
indicate where metrics are actually updated.
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