diff --git a/build/build.js b/build/build.js
index b32ec49fd..6a5f44670 100644
--- a/build/build.js
+++ b/build/build.js
@@ -52,9 +52,9 @@ const configFlat = {
 const packages = fs.readdirSync(path.resolve(process.cwd(), 'packages'));
 console.log(packages);
 for (const package of packages) {
-    if (package !== 'hydrooj') config.references.push({ path: `packages/${package}` });
     const files = fs.readdirSync(path.resolve(process.cwd(), 'packages', package));
     if (!files.includes('src') && !files.map(n => n.split('.')[1]).includes('ts')) continue;
+    if (package !== 'hydrooj') config.references.push({ path: `packages/${package}` });
     fs.writeFileSync(
         path.resolve(process.cwd(), 'packages', package, 'tsconfig.json'),
         files.includes('src') ? JSON.stringify(configSrc) : JSON.stringify(configFlat),
diff --git a/packages/hydrooj/package.json b/packages/hydrooj/package.json
index 55f4695a6..57e860d2c 100644
--- a/packages/hydrooj/package.json
+++ b/packages/hydrooj/package.json
@@ -1,6 +1,6 @@
 {
     "name": "hydrooj",
-    "version": "2.13.23",
+    "version": "2.13.24",
     "bin": "bin/hydrooj.js",
     "main": "dist/loader.js",
     "typings": "dist/loader.d.ts",
diff --git a/packages/hydrooj/src/entry/common.ts b/packages/hydrooj/src/entry/common.ts
index f2943a627..9b08ffe79 100644
--- a/packages/hydrooj/src/entry/common.ts
+++ b/packages/hydrooj/src/entry/common.ts
@@ -18,7 +18,7 @@ export const builtinModel = [
     'builtin', 'document', 'domain', 'blacklist', 'opcount',
     'setting', 'token', 'user', 'problem', 'record',
     'contest', 'message', 'solution', 'training', 'file',
-    'discussion', 'system',
+    'discussion', 'system', 'oplog',
 ];
 
 export const builtinHandler = [
diff --git a/packages/hydrooj/src/handler/discussion.ts b/packages/hydrooj/src/handler/discussion.ts
index fd5f784c5..aed356bc0 100644
--- a/packages/hydrooj/src/handler/discussion.ts
+++ b/packages/hydrooj/src/handler/discussion.ts
@@ -6,6 +6,7 @@ import {
 } from '../interface';
 import paginate from '../lib/paginate';
 import * as user from '../model/user';
+import * as oplog from '../model/oplog';
 import * as message from '../model/message';
 import * as discussion from '../model/discussion';
 import * as document from '../model/document';
@@ -257,6 +258,7 @@ class DiscussionDetailHandler extends DiscussionHandler {
             } else this.checkPerm(PERM.PERM_DELETE_DISCUSSION_SELF);
         }
         await discussion.delReply(domainId, drid);
+        await oplog.add({ ...this.drdoc, operator: this.user._id, type: 'drdoc' });
         this.back();
     }
 
@@ -275,6 +277,7 @@ class DiscussionDetailHandler extends DiscussionHandler {
     async postDeleteTailReply(domainId: string, drid: ObjectID, drrid: ObjectID) {
         if (this.drrdoc.owner !== this.user._id) this.checkPerm(PERM.PERM_DELETE_DISCUSSION_REPLY);
         await discussion.delTailReply(domainId, drid, drrid);
+        await oplog.add({ ...this.drrdoc, operator: this.user._id, type: 'drrdoc' });
         this.back();
     }
 
@@ -348,6 +351,7 @@ class DiscussionEditHandler extends DiscussionHandler {
         if (this.ddoc.owner !== this.user._id) this.checkPerm(PERM.PERM_DELETE_DISCUSSION);
         else this.checkPerm(PERM.PERM_DELETE_DISCUSSION_SELF);
         await discussion.del(domainId, did);
+        await oplog.add({ ...this.ddoc, operator: this.user._id, type: 'ddoc' });
         this.response.body = { type: this.ddoc.parentType, parent: this.ddoc.parentId };
         this.response.redirect = this.url('discussion_node', {
             type: discussion.typeDisplay[this.ddoc.parentType],
diff --git a/packages/hydrooj/src/interface.ts b/packages/hydrooj/src/interface.ts
index a2f0cf319..e7ebad71c 100644
--- a/packages/hydrooj/src/interface.ts
+++ b/packages/hydrooj/src/interface.ts
@@ -374,7 +374,12 @@ export interface TokenDoc {
     [key: string]: any,
 }
 
-export interface ContestStat extends Dictionary<any> {
+export interface OplogDoc extends Record<string, any> {
+    _id: ObjectID,
+    type: string,
+}
+
+export interface ContestStat extends Record<string, any> {
     detail: any,
 }
 
@@ -464,6 +469,7 @@ export interface Collections {
     'oauth': any,
     'system': System,
     'task': Task,
+    'oplog': OplogDoc,
     'opcount': any,
     'fs.chunks': any,
     'fs.files': any,
@@ -486,6 +492,7 @@ export interface Model {
     solution: typeof import('./model/solution'),
     system: typeof import('./model/system'),
     task: typeof import('./model/task'),
+    oplog: typeof import('./model/oplog'),
     token: typeof import('./model/token'),
     training: typeof import('./model/training'),
     user: typeof import('./model/user'),
diff --git a/packages/hydrooj/src/model/oplog.ts b/packages/hydrooj/src/model/oplog.ts
new file mode 100644
index 000000000..ce82a4a05
--- /dev/null
+++ b/packages/hydrooj/src/model/oplog.ts
@@ -0,0 +1,16 @@
+import { ObjectID } from 'mongodb';
+import { OplogDoc } from '../interface';
+import * as db from '../service/db';
+
+export const coll = db.collection('oplog');
+
+export async function add(data: Partial<OplogDoc>): Promise<ObjectID> {
+    const res = await coll.insertOne(data);
+    return res.insertedId;
+}
+
+export async function get(id: ObjectID): Promise<OplogDoc | null> {
+    return await coll.findOne({ _id: id });
+}
+
+global.Hydro.model.oplog = { coll, add, get };