From 4e135a099c4e944954f68d894a165580a997e0f8 Mon Sep 17 00:00:00 2001
From: Michael Lumish <mlumish@google.com>
Date: Wed, 9 Sep 2026 14:58:54 -0700
Subject: [PATCH 1/2] grpc-js: Remove calls from the pick queue immediately
 when they end

---
 packages/grpc-js/src/internal-channel.ts    | 27 +++++++++++++--------
 packages/grpc-js/src/load-balancing-call.ts |  1 +
 2 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/packages/grpc-js/src/internal-channel.ts b/packages/grpc-js/src/internal-channel.ts
index db3827f7b..cc3f5a0af 100644
--- a/packages/grpc-js/src/internal-channel.ts
+++ b/packages/grpc-js/src/internal-channel.ts
@@ -193,7 +193,7 @@ export class InternalChannel {
    * first time the resolver returns a result, which includes the ConfigSelector.
    */
   private configSelectionQueue: ResolvingCall[] = [];
-  private pickQueue: LoadBalancingCall[] = [];
+  private pickQueue: Set<LoadBalancingCall> = new Set();
   private connectivityStateWatchers: ConnectivityStateWatcher[] = [];
   private readonly defaultAuthority: string;
   private readonly filterStackFactory: FilterStackFactory;
@@ -342,9 +342,9 @@ export class InternalChannel {
       },
       updateState: (connectivityState: ConnectivityState, picker: Picker) => {
         this.currentPicker = picker;
-        const queueCopy = this.pickQueue.slice();
-        this.pickQueue = [];
-        if (queueCopy.length > 0) {
+        const queueCopy = {...this.pickQueue};
+        this.pickQueue = new Set();
+        if (queueCopy.size > 0) {
           this.callRefTimerUnref();
         }
         for (const call of queueCopy) {
@@ -479,8 +479,8 @@ export class InternalChannel {
       this.trace(
         'callRefTimer.ref | configSelectionQueue.length=' +
           this.configSelectionQueue.length +
-          ' pickQueue.length=' +
-          this.pickQueue.length
+          ' pickQueue.size=' +
+          this.pickQueue.size
       );
       this.callRefTimer.ref?.();
     }
@@ -492,8 +492,8 @@ export class InternalChannel {
       this.trace(
         'callRefTimer.unref | configSelectionQueue.length=' +
           this.configSelectionQueue.length +
-          ' pickQueue.length=' +
-          this.pickQueue.length
+          ' pickQueue.size=' +
+          this.pickQueue.size
       );
       this.callRefTimer?.unref?.();
     }
@@ -571,10 +571,17 @@ export class InternalChannel {
   }
 
   queueCallForPick(call: LoadBalancingCall) {
-    this.pickQueue.push(call);
+    this.pickQueue.add(call);
     this.callRefTimerRef();
   }
 
+  removeCallFromPickQueue(call: LoadBalancingCall) {
+    this.pickQueue.delete(call);
+    if (this.pickQueue.size === 0) {
+      this.callRefTimerUnref();
+    }
+  }
+
   getConfig(method: string, metadata: Metadata): GetConfigResult {
     if (this.connectivityState !== ConnectivityState.SHUTDOWN) {
       this.resolvingLoadBalancer.exitIdle();
@@ -771,7 +778,7 @@ export class InternalChannel {
     for (const call of this.pickQueue) {
       call.cancelWithStatus(Status.UNAVAILABLE, 'Channel closed before call started');
     }
-    this.pickQueue = [];
+    this.pickQueue.clear();
     if (this.callRefTimer) {
       clearInterval(this.callRefTimer);
     }
diff --git a/packages/grpc-js/src/load-balancing-call.ts b/packages/grpc-js/src/load-balancing-call.ts
index 3ff728985..36014ee4f 100644
--- a/packages/grpc-js/src/load-balancing-call.ts
+++ b/packages/grpc-js/src/load-balancing-call.ts
@@ -128,6 +128,7 @@ export class LoadBalancingCall implements Call, DeadlineInfoProvider {
       const finalStatus = { ...status, progress };
       this.listener?.onReceiveStatus(finalStatus);
       this.onCallEnded?.(finalStatus.code, finalStatus.details, finalStatus.metadata);
+      this.channel.removeCallFromPickQueue(this);
     }
   }
 

From 9bf01da0229f42154f5337488cbb66ffc89915c7 Mon Sep 17 00:00:00 2001
From: Michael Lumish <mlumish@google.com>
Date: Thu, 10 Sep 2026 09:45:10 -0700
Subject: [PATCH 2/2] Don't copy the pick queue to loop over it

Co-authored-by: Sergey Melikyan <55602957+Sermelyan@users.noreply.github.com>
---
 packages/grpc-js/src/internal-channel.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/grpc-js/src/internal-channel.ts b/packages/grpc-js/src/internal-channel.ts
index cc3f5a0af..942d7a449 100644
--- a/packages/grpc-js/src/internal-channel.ts
+++ b/packages/grpc-js/src/internal-channel.ts
@@ -342,7 +342,7 @@ export class InternalChannel {
       },
       updateState: (connectivityState: ConnectivityState, picker: Picker) => {
         this.currentPicker = picker;
-        const queueCopy = {...this.pickQueue};
+        const queueCopy = this.pickQueue;
         this.pickQueue = new Set();
         if (queueCopy.size > 0) {
           this.callRefTimerUnref();