chore: add a metric label is_multiplexed for multiplexed session.

Author: arpan14

google-cloud-spanner/src/main/java/com/google/cloud/spanner/MetricRegistryConstants.java

@@ -79,6 +79,7 @@ class MetricRegistryConstants {
   static final String NUM_SESSIONS_IN_USE = "spanner/num_in_use_sessions";
   static final String NUM_SESSIONS_AVAILABLE = "spanner/num_available_sessions";
   static final String SESSIONS_TYPE = "session_type";
+  static final String IS_MULTIPLEXED = "is_multiplexed";
 
   static final String MAX_IN_USE_SESSIONS_DESCRIPTION =
       "The maximum number of sessions in use during the last 10 minute interval.";

google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionPool.java

@@ -18,6 +18,7 @@
 
 import static com.google.cloud.spanner.MetricRegistryConstants.COUNT;
 import static com.google.cloud.spanner.MetricRegistryConstants.GET_SESSION_TIMEOUTS;
+import static com.google.cloud.spanner.MetricRegistryConstants.IS_MULTIPLEXED;
 import static com.google.cloud.spanner.MetricRegistryConstants.MAX_ALLOWED_SESSIONS;
 import static com.google.cloud.spanner.MetricRegistryConstants.MAX_ALLOWED_SESSIONS_DESCRIPTION;
 import static com.google.cloud.spanner.MetricRegistryConstants.MAX_IN_USE_SESSIONS;
@@ -1402,7 +1403,7 @@ PooledSession get(final boolean eligibleForLongRunning) {
           res.markBusy(span);
           span.addAnnotation("Using Session", "sessionId", res.getName());
           synchronized (lock) {
-            incrementNumSessionsInUse();
+            incrementNumSessionsInUse(false);
             checkedOutSessions.add(this);
           }
           res.eligibleForLongRunning = eligibleForLongRunning;
@@ -2162,9 +2163,15 @@ enum Position {
   @GuardedBy("lock")
   private long numSessionsAcquired = 0;
 
+  @GuardedBy("lock")
+  private long numMultiplexedSessionsAcquired = 0;
+
   @GuardedBy("lock")
   private long numSessionsReleased = 0;
 
+  @GuardedBy("lock")
+  private long numMultiplexedSessionsReleased = 0;
+
   @GuardedBy("lock")
   private long numIdleSessionsRemoved = 0;
 
@@ -2175,6 +2182,7 @@ enum Position {
   private long numLeakedSessionsRemoved = 0;
 
   private AtomicLong numWaiterTimeouts = new AtomicLong();
+  private AtomicLong numMultiplexedSessionWaiterTimeouts = new AtomicLong();
 
   @GuardedBy("lock")
   private final Set<PooledSession> allSessions = new HashSet<>();
@@ -2184,15 +2192,12 @@ enum Position {
   final Set<PooledSessionFuture> checkedOutSessions = new HashSet<>();
 
   private final SessionConsumer sessionConsumer = new SessionConsumerImpl();
-
   @VisibleForTesting Function<PooledSession, Void> idleSessionRemovedListener;
 
   @VisibleForTesting Function<PooledSession, Void> longRunningSessionRemovedListener;
-
   private final CountDownLatch waitOnMinSessionsLatch;
   private final SessionReplacementHandler pooledSessionReplacementHandler =
       new PooledSessionReplacementHandler();
-
   /**
    * Create a session pool with the given options and for the given database. It will also start
    * eagerly creating sessions if {@link SessionPoolOptions#getMinSessions()} is greater than 0.
@@ -2424,6 +2429,10 @@ long getNumWaiterTimeouts() {
     return numWaiterTimeouts.get();
   }
 
+  long getNumMultiplexedSessionWaiterTimeouts() {
+    return numMultiplexedSessionWaiterTimeouts.get();
+  }
+
   private void initPool() {
     synchronized (lock) {
       poolMaintainer.init();
@@ -2557,12 +2566,16 @@ private PooledSessionFuture checkoutSession(
     return res;
   }
 
-  private void incrementNumSessionsInUse() {
+  private void incrementNumSessionsInUse(boolean isMultiplexed) {
     synchronized (lock) {
-      if (maxSessionsInUse < ++numSessionsInUse) {
-        maxSessionsInUse = numSessionsInUse;
+      if (!isMultiplexed) {
+        if (maxSessionsInUse < ++numSessionsInUse) {
+          maxSessionsInUse = numSessionsInUse;
+        }
+        numSessionsAcquired++;
+      } else {
+        numMultiplexedSessionsAcquired++;
       }
-      numSessionsAcquired++;
     }
   }
 
@@ -3139,13 +3152,25 @@ private void initOpenTelemetryMetricsCollection(
               measurement.record(this.sessions.size(), attributesAvailableSessions);
             });
 
+    AttributesBuilder attributesBuilderIsMultiplexed;
+    if (attributes != null) {
+      attributesBuilderIsMultiplexed = attributes.toBuilder();
+    } else {
+      attributesBuilderIsMultiplexed = Attributes.builder();
+    }
+    Attributes attributesRegularSession =
+        attributesBuilderIsMultiplexed.put(IS_MULTIPLEXED, false).build();
+    Attributes attributesMultiplexedSession =
+        attributesBuilderIsMultiplexed.put(IS_MULTIPLEXED, true).build();
     meter
         .counterBuilder(GET_SESSION_TIMEOUTS)
         .setDescription(SESSIONS_TIMEOUTS_DESCRIPTION)
         .setUnit(COUNT)
         .buildWithCallback(
             measurement -> {
-              measurement.record(this.getNumWaiterTimeouts(), attributes);
+              measurement.record(this.getNumWaiterTimeouts(), attributesRegularSession);
+              measurement.record(
+                  this.getNumMultiplexedSessionWaiterTimeouts(), attributesMultiplexedSession);
             });
 
     meter
@@ -3154,7 +3179,8 @@ private void initOpenTelemetryMetricsCollection(
         .setUnit(COUNT)
         .buildWithCallback(
             measurement -> {
-              measurement.record(this.numSessionsAcquired, attributes);
+              measurement.record(this.numSessionsAcquired, attributesRegularSession);
+              measurement.record(this.numMultiplexedSessionsAcquired, attributesMultiplexedSession);
             });
 
     meter
@@ -3163,7 +3189,8 @@ private void initOpenTelemetryMetricsCollection(
         .setUnit(COUNT)
         .buildWithCallback(
             measurement -> {
-              measurement.record(this.numSessionsReleased, attributes);
+              measurement.record(this.numSessionsReleased, attributesRegularSession);
+              measurement.record(this.numMultiplexedSessionsReleased, attributesMultiplexedSession);
             });
   }
 }