diff --git a/apps/webapp/app/v3/eventRepository.server.ts b/apps/webapp/app/v3/eventRepository.server.ts
index 067302aba9..7d1625395f 100644
--- a/apps/webapp/app/v3/eventRepository.server.ts
+++ b/apps/webapp/app/v3/eventRepository.server.ts
@@ -326,6 +326,43 @@ export class EventRepository {
     });
   }
 
+  async cancelEvents(events: TaskEventRecord[], cancelledAt: Date, reason: string) {
+    const eventsToCancel = events.filter((event) => event.isPartial);
+
+    if (eventsToCancel.length === 0) {
+      return;
+    }
+
+    await this.insertMany(
+      eventsToCancel.map((event) => ({
+        ...omit(event, "id"),
+        isPartial: false,
+        isError: false,
+        isCancelled: true,
+        status: "ERROR",
+        links: event.links ?? [],
+        events: [
+          {
+            name: "cancellation",
+            time: cancelledAt,
+            properties: {
+              reason,
+            },
+          },
+          ...((event.events as any[]) ?? []),
+        ],
+        duration: calculateDurationFromStart(event.startTime, cancelledAt),
+        properties: event.properties as Attributes,
+        metadata: event.metadata as Attributes,
+        style: event.style as Attributes,
+        output: event.output as Attributes,
+        outputType: event.outputType,
+        payload: event.payload as Attributes,
+        payloadType: event.payloadType,
+      }))
+    );
+  }
+
   async crashEvent({
     event,
     crashedAt,
@@ -394,28 +431,35 @@ export class EventRepository {
       queryOptions,
       startCreatedAt,
       endCreatedAt,
-      { spanId: true, isPartial: true, isCancelled: true }
+      { spanId: true, isPartial: true, isCancelled: true },
+      undefined,
+      { limit: 500 }
     );
 
-    const filteredTaskEvents = taskEvents.filter((event) => {
-      // Event must be partial
-      if (!event.isPartial) return false;
-
-      // If the event is cancelled, it is not incomplete
-      if (event.isCancelled) return false;
-
-      if (allowCompleteDuplicate) {
-        return true;
+    // Optimize the filtering by pre-processing the data
+    const completeEventSpanIds = new Set<string>();
+    const incompleteEvents: Array<{ spanId: string }> = [];
+
+    // Single pass to categorize events and build lookup structures
+    for (const event of taskEvents) {
+      if (!event.isPartial && !event.isCancelled) {
+        // This is a complete event
+        completeEventSpanIds.add(event.spanId);
+      } else if (event.isPartial && !event.isCancelled) {
+        // This is a potentially incomplete event
+        incompleteEvents.push(event);
       }
+      // Skip cancelled events as they are not incomplete
+    }
 
-      // There must not be another complete event with the same spanId
-      const hasCompleteDuplicate = taskEvents.some(
-        (otherEvent) =>
-          otherEvent.spanId === event.spanId && !otherEvent.isPartial && !otherEvent.isCancelled
-      );
+    // Filter incomplete events, excluding those with complete duplicates
+    const filteredTaskEvents = allowCompleteDuplicate
+      ? incompleteEvents
+      : incompleteEvents.filter((event) => !completeEventSpanIds.has(event.spanId));
 
-      return !hasCompleteDuplicate;
-    });
+    if (filteredTaskEvents.length === 0) {
+      return [];
+    }
 
     return this.#queryEvents(
       storeTable,
diff --git a/apps/webapp/app/v3/runEngineHandlers.server.ts b/apps/webapp/app/v3/runEngineHandlers.server.ts
index 2767e613db..2c2ed59a8a 100644
--- a/apps/webapp/app/v3/runEngineHandlers.server.ts
+++ b/apps/webapp/app/v3/runEngineHandlers.server.ts
@@ -309,12 +309,9 @@ export function registerRunEngineEventBusHandlers() {
         run.completedAt ?? undefined
       );
 
-      await Promise.all(
-        inProgressEvents.map((event) => {
-          const error = createJsonErrorObject(run.error);
-          return eventRepository.cancelEvent(event, time, error.message);
-        })
-      );
+      const error = createJsonErrorObject(run.error);
+
+      await eventRepository.cancelEvents(inProgressEvents, time, error.message);
     } catch (error) {
       logger.error("[runCancelled] Failed to cancel event", {
         error: error instanceof Error ? error.message : error,
diff --git a/apps/webapp/app/v3/services/cancelTaskRunV1.server.ts b/apps/webapp/app/v3/services/cancelTaskRunV1.server.ts
index 78aec652f7..1a8c136e5c 100644
--- a/apps/webapp/app/v3/services/cancelTaskRunV1.server.ts
+++ b/apps/webapp/app/v3/services/cancelTaskRunV1.server.ts
@@ -95,13 +95,10 @@ export class CancelTaskRunServiceV1 extends BaseService {
 
     logger.debug("Cancelling in-progress events", {
       inProgressEvents: inProgressEvents.map((event) => event.id),
+      eventCount: inProgressEvents.length,
     });
 
-    await Promise.all(
-      inProgressEvents.map((event) => {
-        return eventRepository.cancelEvent(event, opts.cancelledAt, opts.reason);
-      })
-    );
+    await eventRepository.cancelEvents(inProgressEvents, opts.cancelledAt, opts.reason);
 
     // Cancel any in progress attempts
     if (opts.cancelAttempts) {
diff --git a/apps/webapp/app/v3/taskEventStore.server.ts b/apps/webapp/app/v3/taskEventStore.server.ts
index 1f926e89f8..7a87d29b35 100644
--- a/apps/webapp/app/v3/taskEventStore.server.ts
+++ b/apps/webapp/app/v3/taskEventStore.server.ts
@@ -77,7 +77,7 @@ export class TaskEventStore {
     endCreatedAt?: Date,
     select?: TSelect,
     orderBy?: Prisma.TaskEventOrderByWithRelationInput,
-    options?: { includeDebugLogs?: boolean }
+    options?: { includeDebugLogs?: boolean; limit?: number }
   ): Promise<Prisma.TaskEventGetPayload<{ select: TSelect }>[]> {
     let finalWhere: Prisma.TaskEventWhereInput = where;
 
@@ -111,6 +111,7 @@ export class TaskEventStore {
         },
         select,
         orderBy,
+        take: options?.limit,
       })) as Prisma.TaskEventGetPayload<{ select: TSelect }>[];
     } else {
       // When partitioning is not enabled, we ignore the createdAt range.
@@ -121,6 +122,7 @@ export class TaskEventStore {
         },
         select,
         orderBy,
+        take: options?.limit,
       })) as Prisma.TaskEventGetPayload<{ select: TSelect }>[];
     }
   }