feat(bigquery-jdbc): implement non-blocking telemetry batcher and dispatcher

java-bigquery-jdbc/src/main/java/com/google/cloud/bigquery/jdbc/telemetry/v1/TelemetryBatcher.java

@@ -0,0 +1,354 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed 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
+ *
+ * https://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 com.google.cloud.bigquery.jdbc.telemetry.v1;
+
+import com.google.cloud.bigquery.jdbc.BigQueryJdbcCustomLogger;
+import com.google.protobuf.Timestamp;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Queue;
+import java.util.concurrent.Executors;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * High-performance, non-blocking telemetry event batcher and periodic dispatcher. Buffers
+ * connection, statement, error, and feature usage telemetry events in memory and flushes them to
+ * Clearcut via {@link ClearcutTransport}.
+ */
+final class TelemetryBatcher implements AutoCloseable {
+  private static final Logger logger =
+      new BigQueryJdbcCustomLogger(TelemetryBatcher.class.getName());
+  private static final int MAX_QUEUE_SIZE = 10_000;
+  private static final int MAX_PAYLOAD_BYTES = 512 * 1024; // 512 KB payload size limit
+
+  private final TelemetryConfiguration config;
+  private final ClearcutTransport transport;
+  private final DriverEnvironment driverEnvironment;
+  private final ScheduledExecutorService executorService;
+  private final boolean ownsExecutor;
+  private final ReentrantLock flushLock = new ReentrantLock();
+
+  private final Queue<ConnectionAttempt> connectionAttemptQueue =
+      new LinkedBlockingQueue<>(MAX_QUEUE_SIZE);
+  private final Queue<StatementExecution> statementExecutionQueue =
+      new LinkedBlockingQueue<>(MAX_QUEUE_SIZE);
+  private final Queue<ErrorMetric> errorMetricQueue = new LinkedBlockingQueue<>(MAX_QUEUE_SIZE);
+  private final Queue<FeatureUsage> featureUsageQueue = new LinkedBlockingQueue<>(MAX_QUEUE_SIZE);
+
+  private final AtomicBoolean isClosed = new AtomicBoolean(false);
+  private final AtomicLong currentScheduleDelayMs = new AtomicLong(-1);
+  private ScheduledFuture<?> scheduledTask;
+
+  TelemetryBatcher(TelemetryConfiguration config, ClearcutTransport transport) {
+    this(
+        config,
+        transport,
+        Executors.newSingleThreadScheduledExecutor(
+            r -> {
+              Thread t = new Thread(r, "jdbc-telemetry-batcher");
+              t.setDaemon(true);
+              return t;
+            }),
+        true);
+  }
+
+  // Package-private constructor for testing overrides
+  TelemetryBatcher(
+      TelemetryConfiguration config,
+      ClearcutTransport transport,
+      ScheduledExecutorService executorService,
+      boolean ownsExecutor) {
+    this.config = config;
+    this.transport = transport;
+    this.driverEnvironment = config != null ? config.getDriverEnvironment() : null;
+    this.executorService = executorService;
+    this.ownsExecutor = ownsExecutor;
+
+    if (this.config != null && this.config.isEnabled()) {
+      reschedule(this.config.getUploadIntervalMs());
+    }
+  }
+
+  void offerConnectionAttempt(ConnectionAttempt attempt) {
+    offerMetric(connectionAttemptQueue, attempt, "Connection attempt");
+  }
+
+  void offerStatementExecution(StatementExecution execution) {
+    offerMetric(statementExecutionQueue, execution, "Statement execution");
+  }
+
+  void offerErrorMetric(ErrorMetric errorMetric) {
+    offerMetric(errorMetricQueue, errorMetric, "Error metric");
+  }
+
+  void offerFeatureUsage(FeatureUsage featureUsage) {
+    offerMetric(featureUsageQueue, featureUsage, "Feature usage");
+  }
+
+  private <T> void offerMetric(Queue<T> queue, T item, String metricName) {
+    if (isClosed.get() || !isConfigured() || item == null) {
+      return;
+    }
+    if (!queue.offer(item)) {
+      logger.log(Level.WARNING, metricName + " telemetry queue full. Dropping metric.");
+    }
+  }
+
+  TransportResult flush() {
+    flushLock.lock();
+    try {
+      if (!isConfigured() || isEmpty()) {
+        return TransportResult.disabled();
+      }
+
+      int maxTotalBatchSize =
+          config != null
+              ? config.getBatchSizeThreshold()
+              : TelemetryConfiguration.DEFAULT_BATCH_SIZE_THRESHOLD;
+
+      List<ConnectionAttempt> connectionAttempts = new ArrayList<>();
+      List<StatementExecution> statementExecutions = new ArrayList<>();
+      List<ErrorMetric> errorMetrics = new ArrayList<>();
+      List<FeatureUsage> featureUsages = new ArrayList<>();
+
+      int remainingQuota = maxTotalBatchSize;
+      remainingQuota -= drainQueue(connectionAttemptQueue, connectionAttempts, remainingQuota);
+      remainingQuota -= drainQueue(statementExecutionQueue, statementExecutions, remainingQuota);
+      remainingQuota -= drainQueue(errorMetricQueue, errorMetrics, remainingQuota);
+      remainingQuota -= drainQueue(featureUsageQueue, featureUsages, remainingQuota);
+
+      if (connectionAttempts.isEmpty()
+          && statementExecutions.isEmpty()
+          && errorMetrics.isEmpty()
+          && featureUsages.isEmpty()) {
+        return TransportResult.disabled();
+      }
+
+      Instant now = Instant.now();
+      Timestamp timestamp =
+          Timestamp.newBuilder().setSeconds(now.getEpochSecond()).setNanos(now.getNano()).build();
+
+      TelemetryPayload.Builder payloadBuilder =
+          TelemetryPayload.newBuilder().setEventTime(timestamp);
+      if (driverEnvironment != null) {
+        payloadBuilder.setDriverEnvironment(driverEnvironment);
+      }
+      payloadBuilder.addAllConnectionAttempts(connectionAttempts);
+      payloadBuilder.addAllStatementExecutions(statementExecutions);
+      payloadBuilder.addAllErrors(errorMetrics);
+      payloadBuilder.addAllFeatureUsages(featureUsages);
+
+      TelemetryPayload payload = payloadBuilder.build();
+
+      // Enforce MAX_PAYLOAD_BYTES (512 KB) by estimating bulk trim with safety padding
+      int currentSize = payload.getSerializedSize();
+      if (currentSize > MAX_PAYLOAD_BYTES) {
+        int totalItems =
+            connectionAttempts.size()
+                + statementExecutions.size()
+                + errorMetrics.size()
+                + featureUsages.size();
+        if (totalItems > 0) {
+          double avgBytesPerItem = (double) currentSize / totalItems;
+          int excessBytes = currentSize - MAX_PAYLOAD_BYTES;
+          // Add +5 items safety pad to guarantee 100% single-pass size compliance
+          int itemsToTrim =
+              Math.min(totalItems, (int) Math.ceil(excessBytes / avgBytesPerItem) + 5);
+
+          trimExcessItemsBulk(
+              itemsToTrim, connectionAttempts, statementExecutions, errorMetrics, featureUsages);
+
+          payloadBuilder
+              .clearConnectionAttempts()
+              .addAllConnectionAttempts(connectionAttempts)
+              .clearStatementExecutions()
+              .addAllStatementExecutions(statementExecutions)
+              .clearErrors()
+              .addAllErrors(errorMetrics)
+              .clearFeatureUsages()
+              .addAllFeatureUsages(featureUsages);
+          payload = payloadBuilder.build();
+        }
+      }
+
+      TransportResult result;
+      try {
+        result = transport.send(payload);
+      } catch (Throwable t) {
+        logger.log(Level.WARNING, "Unexpected exception during telemetry flush", t);
+        result = new TransportResult(false, -1);
+      }
+
+      if (!result.isSuccess()) {
+        requeueItems(connectionAttemptQueue, connectionAttempts);
+        requeueItems(statementExecutionQueue, statementExecutions);
+        requeueItems(errorMetricQueue, errorMetrics);
+        requeueItems(featureUsageQueue, featureUsages);
+      }
+
+      long uploadIntervalMs = config != null ? config.getUploadIntervalMs() : 300_000L;
+      long newDelayMs =
+          result.getNextRequestWaitMillis() > 0
+              ? Math.max(uploadIntervalMs, result.getNextRequestWaitMillis())
+              : uploadIntervalMs;
+      reschedule(newDelayMs);
+
+      return result;
+    } finally {
+      flushLock.unlock();
+    }
+  }
+
+  @Override
+  public void close() {
+    if (!isClosed.compareAndSet(false, true)) {
+      return;
+    }
+
+    flushLock.lock();
+    try {
+      if (scheduledTask != null) {
+        scheduledTask.cancel(false);
+      }
+    } finally {
+      flushLock.unlock();
+    }
+
+    try {
+      flush();
+    } catch (Throwable t) {
+      logger.log(Level.WARNING, "Error during final telemetry batcher flush", t);
+    }
+
+    if (ownsExecutor && executorService != null) {
+      executorService.shutdown();
+      try {
+        if (!executorService.awaitTermination(3, TimeUnit.SECONDS)) {
+          executorService.shutdownNow();
+        }
+      } catch (InterruptedException e) {
+        executorService.shutdownNow();
+        Thread.currentThread().interrupt();
+      }
+    }
+  }
+
+  boolean isEmpty() {
+    return connectionAttemptQueue.isEmpty()
+        && statementExecutionQueue.isEmpty()
+        && errorMetricQueue.isEmpty()
+        && featureUsageQueue.isEmpty();
+  }
+
+  int getPendingEventCount() {
+    return connectionAttemptQueue.size()
+        + statementExecutionQueue.size()
+        + errorMetricQueue.size()
+        + featureUsageQueue.size();
+  }
+
+  private boolean isConfigured() {
+    return config != null && config.isEnabled() && transport != null;
+  }
+
+  private void reschedule(long delayMs) {
+    if (isClosed.get() || executorService == null || executorService.isShutdown()) {
+      return;
+    }
+    long effectiveDelay = Math.max(1L, delayMs);
+
+    flushLock.lock();
+    try {
+      if (currentScheduleDelayMs.get() == effectiveDelay
+          && scheduledTask != null
+          && !scheduledTask.isDone()) {
+        return;
+      }
+
+      if (scheduledTask != null) {
+        scheduledTask.cancel(false);
+      }
+
+      currentScheduleDelayMs.set(effectiveDelay);
+      scheduledTask =
+          executorService.scheduleWithFixedDelay(
+              () -> {
+                try {
+                  flush();
+                } catch (Throwable t) {
+                  logger.log(Level.WARNING, "Periodic telemetry flush encountered an exception", t);
+                }
+              },
+              effectiveDelay,
+              effectiveDelay,
+              TimeUnit.MILLISECONDS);
+    } finally {
+      flushLock.unlock();
+    }
+  }
+
+  private void trimExcessItemsBulk(
+      int itemsToTrim,
+      List<ConnectionAttempt> connectionAttempts,
+      List<StatementExecution> statementExecutions,
+      List<ErrorMetric> errorMetrics,
+      List<FeatureUsage> featureUsages) {
+    int remainingToTrim = itemsToTrim;
+
+    while (remainingToTrim > 0 && !featureUsages.isEmpty()) {
+      featureUsageQueue.offer(featureUsages.remove(featureUsages.size() - 1));
+      remainingToTrim--;
+    }
+    while (remainingToTrim > 0 && !errorMetrics.isEmpty()) {
+      errorMetricQueue.offer(errorMetrics.remove(errorMetrics.size() - 1));
+      remainingToTrim--;
+    }
+    while (remainingToTrim > 0 && !statementExecutions.isEmpty()) {
+      statementExecutionQueue.offer(statementExecutions.remove(statementExecutions.size() - 1));
+      remainingToTrim--;
+    }
+    while (remainingToTrim > 0 && !connectionAttempts.isEmpty()) {
+      connectionAttemptQueue.offer(connectionAttempts.remove(connectionAttempts.size() - 1));
+      remainingToTrim--;
+    }
+  }
+
+  private <T> int drainQueue(Queue<T> queue, List<T> targetList, int maxItems) {
+    int count = 0;
+    T item;
+    while (count < maxItems && (item = queue.poll()) != null) {
+      targetList.add(item);
+      count++;
+    }
+    return count;
+  }
+
+  private <T> void requeueItems(Queue<T> queue, List<T> items) {
+    if (items != null && !items.isEmpty()) {
+      queue.addAll(items);
+    }
+  }
+}

java-bigquery-jdbc/src/main/java/com/google/cloud/bigquery/jdbc/telemetry/v1/TelemetryConfiguration.java

@@ -25,7 +25,7 @@ final class TelemetryConfiguration {
   static final int DEFAULT_LOG_SOURCE = -1;
   static final String DEFAULT_ENDPOINT_URL = "https://play.googleapis.com/log";
   static final long DEFAULT_UPLOAD_INTERVAL_MS = 300_000L;
-  static final int DEFAULT_BATCH_SIZE_THRESHOLD = 100;
+  static final int DEFAULT_BATCH_SIZE_THRESHOLD = 5000;
 
   private final boolean enabled;
   private final int logSource;