fix: Fixed high CPU usage due to pending JS commands (#22024) (#22035) (#22049)

mshabarov · web-flow · commit 9a5095d4d44e · 2025-08-18T09:45:56.000+03:00
Field "pendingJsInvocations" should be a Set instead of a List in order to avoid O(n^2) operations. This greatly improves performance in situations where many fields are updated constantly and the JS command queue becomes very large. Fixes #22024
diff --git a/flow-server/src/main/java/com/vaadin/flow/component/internal/UIInternals.java b/flow-server/src/main/java/com/vaadin/flow/component/internal/UIInternals.java
@@ -14,6 +14,7 @@
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.IdentityHashMap;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
@@ -165,7 +166,7 @@ public List<Object> getParameters() {
      */
     private long lastHeartbeatTimestamp = System.currentTimeMillis();
 
-    private List<PendingJavaScriptInvocation> pendingJsInvocations = new ArrayList<>();
+    private Set<PendingJavaScriptInvocation> pendingJsInvocations = new LinkedHashSet<>();
 
     private final HashMap<StateNode, PendingJavaScriptInvocationDetachListener> pendingJsInvocationDetachListeners = new HashMap<>();
 
@@ -572,7 +573,7 @@ public List<PendingJavaScriptInvocation> dumpPendingJavaScriptInvocations() {
 
         pendingJsInvocations = getPendingJavaScriptInvocations()
                 .filter(invocation -> !invocation.getOwner().isVisible())
-                .collect(Collectors.toCollection(ArrayList::new));
+                .collect(Collectors.toCollection(LinkedHashSet::new));
         pendingJsInvocations
                 .forEach(this::registerDetachListenerForPendingInvocation);
         return readyToSend;
@@ -615,8 +616,7 @@ public void execute() {
 
         private void removePendingInvocation(
                 PendingJavaScriptInvocation invocation) {
-            UIInternals.this.pendingJsInvocations.removeIf(
-                    pendingInvocation -> pendingInvocation.equals(invocation));
+            UIInternals.this.pendingJsInvocations.remove(invocation);
             if (invocationList.isEmpty() && registration != null) {
                 registration.remove();
                 registration = null;
