No volatile variables

jack-berg · Nov 10, 2023 · 60c2b43 · 60c2b43
1 parent 55b845a
commit 60c2b43
Showing 1 changed file with 12 additions and 4 deletions.
diff --git a/...ain/java/io/opentelemetry/sdk/metrics/internal/state/DefaultSynchronousMetricStorage.java b/...ain/java/io/opentelemetry/sdk/metrics/internal/state/DefaultSynchronousMetricStorage.java
@@ -26,6 +26,7 @@
 import java.util.Queue;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReadWriteLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
@@ -49,7 +50,9 @@ public final class DefaultSynchronousMetricStorage<T extends PointData, U extend
   private final MetricDescriptor metricDescriptor;
   private final AggregationTemporality aggregationTemporality;
   private final Aggregator<T, U> aggregator;
-  private volatile AggregatorHolder<T, U> aggregatorHolder = new AggregatorHolder<>();
+  private final AtomicInteger collectCount = new AtomicInteger();
+  private final AggregatorHolder<T, U> holder1 = new AggregatorHolder<>();
+  private final AggregatorHolder<T, U> holder2 = new AggregatorHolder<>();
   private final AttributesProcessor attributesProcessor;
 
   /**
@@ -85,6 +88,7 @@ Queue<AggregatorHandle<T, U>> getAggregatorHandlePool() {
 
   @Override
   public void recordLong(long value, Attributes attributes, Context context) {
+    AggregatorHolder<T, U> aggregatorHolder = collectCount.get() % 2 == 0 ? holder1 : holder2;
     Lock readLock = aggregatorHolder.lock.readLock();
     readLock.lock();
     try {
@@ -108,6 +112,7 @@ public void recordDouble(double value, Attributes attributes, Context context) {
               + ". Dropping measurement.");
       return;
     }
+    AggregatorHolder<T, U> aggregatorHolder = collectCount.get() % 2 == 0 ? holder1 : holder2;
     Lock readLock = aggregatorHolder.lock.readLock();
     readLock.lock();
     try {
@@ -167,8 +172,7 @@ public MetricData collect(
 
     ConcurrentHashMap<Attributes, AggregatorHandle<T, U>> aggregatorHandles;
     if (reset) {
-      AggregatorHolder<T, U> holder = this.aggregatorHolder;
-      this.aggregatorHolder = new AggregatorHolder<>();
+      AggregatorHolder<T, U> holder = collectCount.getAndIncrement() % 2 == 0 ? holder1 : holder2;
       Lock writeLock = holder.lock.writeLock();
       writeLock.lock();
       try {
@@ -177,7 +181,7 @@ public MetricData collect(
         writeLock.unlock();
       }
     } else {
-      aggregatorHandles = this.aggregatorHolder.aggregatorHandles;
+      aggregatorHandles = holder1.aggregatorHandles;
     }
 
     // Grab aggregated points.
@@ -201,6 +205,10 @@ public MetricData collect(
       aggregatorHandlePool.poll();
     }
 
+    if (reset) {
+      aggregatorHandles.clear();
+    }
+
     if (points.isEmpty()) {
       return EmptyMetricData.getInstance();
     }