diff --git a/packages/hydrooj/src/handler/contest.ts b/packages/hydrooj/src/handler/contest.ts
index e32a7372a..7dbca825e 100644
--- a/packages/hydrooj/src/handler/contest.ts
+++ b/packages/hydrooj/src/handler/contest.ts
@@ -18,7 +18,6 @@ import message from '../model/message';
 import * as oplog from '../model/oplog';
 import problem from '../model/problem';
 import record from '../model/record';
-import RecordModel from '../model/record';
 import ScheduleModel from '../model/schedule';
 import storage from '../model/storage';
 import * as system from '../model/system';
diff --git a/packages/prom-client/metrics.ts b/packages/prom-client/metrics.ts
index 405135dc5..27268c18d 100644
--- a/packages/prom-client/metrics.ts
+++ b/packages/prom-client/metrics.ts
@@ -68,6 +68,13 @@ export function createRegistry(ctx: Context) {
         labelNames: ['type'],
     });
 
+    const eventCounter = createMetric(Counter, 'hydro_eventcount', 'eventcount', {
+        labelNames: ['name'],
+    });
+    ctx.on('bus/broadcast', (name) => {
+        eventCounter.inc({ name });
+    });
+
     collectDefaultMetrics({ register: registry });
 
     ctx.metrics = registry;