diff --git a/packages/hydrooj/src/handler/status.ts b/packages/hydrooj/src/handler/status.ts
index 0b3de992f..5d0137aef 100644
--- a/packages/hydrooj/src/handler/status.ts
+++ b/packages/hydrooj/src/handler/status.ts
@@ -39,11 +39,11 @@ class AdminStatusHandler extends Handler {
         const record = await RecordModel.stat();
         const status = await getStatus();
         const [domainCount, userCount, problemCount, discussionCount, recordCount] = await Promise.all([
-            DomainModel.coll.countDocuments(),
-            UserModel.coll.countDocuments(),
-            DocumentModel.coll.countDocuments({ docType: DocumentModel.TYPE_PROBLEM }),
-            DocumentModel.coll.countDocuments({ docType: DocumentModel.TYPE_DISCUSSION }),
-            RecordModel.coll.countDocuments(),
+            DomainModel.coll.count(),
+            UserModel.coll.count(),
+            DocumentModel.coll.count({ docType: DocumentModel.TYPE_PROBLEM }),
+            DocumentModel.coll.count({ docType: DocumentModel.TYPE_DISCUSSION }),
+            RecordModel.coll.count(),
         ]);
         this.response.body = {
             record,
diff --git a/packages/hydrooj/src/lib/paginate.ts b/packages/hydrooj/src/lib/paginate.ts
index bf3da8fd7..59b3b7f79 100644
--- a/packages/hydrooj/src/lib/paginate.ts
+++ b/packages/hydrooj/src/lib/paginate.ts
@@ -12,8 +12,9 @@ async function paginate<T>(
         filter = cursor[key];
         break;
     }
+    const coll = db.collection(cursor.namespace.collection as any);
     const [count, pageDocs] = await Promise.all([
-        db.collection(cursor.namespace.collection as any).countDocuments(filter),
+        Object.keys(filter).length ? coll.count(filter) : coll.countDocuments(filter),
         cursor.skip((page - 1) * pageSize).limit(pageSize).toArray(),
     ]);
     const numPages = Math.floor((count + pageSize - 1) / pageSize);
diff --git a/packages/hydrooj/src/model/contest.ts b/packages/hydrooj/src/model/contest.ts
index a8fe73f6b..de0626b2b 100644
--- a/packages/hydrooj/src/model/contest.ts
+++ b/packages/hydrooj/src/model/contest.ts
@@ -986,6 +986,7 @@ export const statusText = (tdoc: Tdoc, tsdoc?: any) => (
 
 global.Hydro.model.contest = {
     RULES,
+    buildContestRule,
     add,
     getListStatus,
     getMultiStatus,
diff --git a/packages/hydrooj/src/model/record.ts b/packages/hydrooj/src/model/record.ts
index 3d5344da8..7dfa77a75 100644
--- a/packages/hydrooj/src/model/record.ts
+++ b/packages/hydrooj/src/model/record.ts
@@ -49,14 +49,17 @@ export default class RecordModel {
 
     @ArgMethod
     static async stat(domainId?: string) {
+        // INFO:
+        // using .count() for a much better performace
+        // @see https://www.mongodb.com/docs/manual/reference/command/count/
         const [d5min, d1h, day, week, month, year, total] = await Promise.all([
-            RecordModel.coll.countDocuments({ _id: { $gte: Time.getObjectID(moment().add(-5, 'minutes')) }, ...domainId ? { domainId } : {} }),
-            RecordModel.coll.countDocuments({ _id: { $gte: Time.getObjectID(moment().add(-1, 'hour')) }, ...domainId ? { domainId } : {} }),
-            RecordModel.coll.countDocuments({ _id: { $gte: Time.getObjectID(moment().add(-1, 'day')) }, ...domainId ? { domainId } : {} }),
-            RecordModel.coll.countDocuments({ _id: { $gte: Time.getObjectID(moment().add(-1, 'week')) }, ...domainId ? { domainId } : {} }),
-            RecordModel.coll.countDocuments({ _id: { $gte: Time.getObjectID(moment().add(-1, 'month')) }, ...domainId ? { domainId } : {} }),
-            RecordModel.coll.countDocuments({ _id: { $gte: Time.getObjectID(moment().add(-1, 'year')) }, ...domainId ? { domainId } : {} }),
-            RecordModel.coll.countDocuments(domainId ? { domainId } : {}),
+            RecordModel.coll.find({ _id: { $gte: Time.getObjectID(moment().add(-5, 'minutes')) }, ...domainId ? { domainId } : {} }).count(),
+            RecordModel.coll.find({ _id: { $gte: Time.getObjectID(moment().add(-1, 'hour')) }, ...domainId ? { domainId } : {} }).count(),
+            RecordModel.coll.find({ _id: { $gte: Time.getObjectID(moment().add(-1, 'day')) }, ...domainId ? { domainId } : {} }).count(),
+            RecordModel.coll.find({ _id: { $gte: Time.getObjectID(moment().add(-1, 'week')) }, ...domainId ? { domainId } : {} }).count(),
+            RecordModel.coll.find({ _id: { $gte: Time.getObjectID(moment().add(-1, 'month')) }, ...domainId ? { domainId } : {} }).count(),
+            RecordModel.coll.find({ _id: { $gte: Time.getObjectID(moment().add(-1, 'year')) }, ...domainId ? { domainId } : {} }).count(),
+            RecordModel.coll.find(domainId ? { domainId } : {}).count(),
         ]);
         return {
             d5min, d1h, day, week, month, year, total,
diff --git a/packages/hydrooj/src/service/monitor.ts b/packages/hydrooj/src/service/monitor.ts
index 893b3e476..7fc17223f 100644
--- a/packages/hydrooj/src/service/monitor.ts
+++ b/packages/hydrooj/src/service/monitor.ts
@@ -18,11 +18,11 @@ export async function feedback(): Promise<[string, StatusUpdate]> {
     const [mid, $update, inf] = await sysinfo.update();
     const [installId, name, url] = system.getMany(['installid', 'server.name', 'server.url']);
     const [domainCount, userCount, problemCount, discussionCount, recordCount] = await Promise.all([
-        domain.coll.countDocuments(),
-        user.coll.countDocuments(),
-        document.coll.countDocuments({ docType: document.TYPE_PROBLEM }),
-        document.coll.countDocuments({ docType: document.TYPE_DISCUSSION }),
-        record.coll.countDocuments(),
+        domain.coll.count(),
+        user.coll.count(),
+        document.coll.count({ docType: document.TYPE_PROBLEM }),
+        document.coll.count({ docType: document.TYPE_DISCUSSION }),
+        record.coll.count(),
     ]);
     const info: Record<string, any> = {
         mid: mid.toString(),