diff --git a/hydro/entry/master.ts b/hydro/entry/master.ts
index 1ed4254e1..18718925c 100644
--- a/hydro/entry/master.ts
+++ b/hydro/entry/master.ts
@@ -32,9 +32,9 @@ export async function load(call: Entry) {
     require('../lib/i18n');
     require('../utils');
     require('../error');
-    try {
-        require('../options').default();
-    } catch (e) {
+    const config = require('../options').default();
+    if (!config) {
+        console.log('Starting setup');
         await call({ entry: 'setup', newProcess: true }).catch((err) => {
             console.error('Cannot start setup process.', err);
             process.exit(1);
diff --git a/hydro/handler/contest.ts b/hydro/handler/contest.ts
index 7ff894b61..af4525480 100644
--- a/hydro/handler/contest.ts
+++ b/hydro/handler/contest.ts
@@ -8,14 +8,13 @@ import {
 } from '../error';
 import { isContent, isTitle } from '../lib/validator';
 import paginate from '../lib/paginate';
-import { PERM, PRIV } from '../model/builtin';
+import { PERM, PRIV, CONSTANT } from '../model/builtin';
 import * as contest from '../model/contest';
 import * as document from '../model/document';
 import * as problem from '../model/problem';
 import * as record from '../model/record';
 import * as user from '../model/user';
 import * as message from '../model/message';
-import * as system from '../model/system';
 import {
     Route, Handler, Types, param,
 } from '../service/server';
@@ -40,7 +39,7 @@ class ContestListHandler extends ContestHandler {
             qs = `rule=${rule}`;
         }
         // eslint-disable-next-line prefer-const
-        [tdocs, tpcount] = await paginate(tdocs, page, await system.get('CONTEST_PER_PAGE'));
+        [tdocs, tpcount] = await paginate(tdocs, page, CONSTANT.CONTEST_PER_PAGE);
         const tids = [];
         for (const tdoc of tdocs) tids.push(tdoc.docId);
         const tsdict = await contest.getListStatus(domainId, this.user._id, tids);
diff --git a/hydro/handler/discussion.ts b/hydro/handler/discussion.ts
index 2fd7ac46d..055d5d4b9 100644
--- a/hydro/handler/discussion.ts
+++ b/hydro/handler/discussion.ts
@@ -1,14 +1,15 @@
 import { ObjectID } from 'mongodb';
 import { isSafeInteger } from 'lodash';
 import { DiscussionNotFoundError, DocumentNotFoundError } from '../error';
-import { Drdoc, Mdoc } from '../interface';
+import {
+    Mdoc, Drdoc, Ddoc, Drrdoc,
+} from '../interface';
 import paginate from '../lib/paginate';
-import * as system from '../model/system';
 import * as user from '../model/user';
 import * as message from '../model/message';
 import * as discussion from '../model/discussion';
 import * as document from '../model/document';
-import { PERM, PRIV } from '../model/builtin';
+import { PERM, PRIV, CONSTANT } from '../model/builtin';
 import {
     Route, Handler, Types, param,
 } from '../service/server';
@@ -23,46 +24,45 @@ export const typeMapper = {
 };
 
 class DiscussionHandler extends Handler {
-    ddoc?: any;
+    ddoc?: Ddoc;
 
-    drdoc?: any;
+    drdoc?: Drdoc;
 
-    drrdoc?: any;
+    drrdoc?: Drrdoc;
 
     vnode?: any;
 
-    async _prepare({
-        domainId, type, name, did, drid, drrid,
-    }) {
+    @param('type', Types.String, true)
+    @param('name', Types.String, true)
+    @param('did', Types.ObjectID, true)
+    @param('drid', Types.ObjectID, true)
+    @param('drrid', Types.ObjectID, true)
+    async _prepare(
+        domainId: string, type: string, name: string,
+        did: ObjectID, drid: ObjectID, drrid: ObjectID,
+    ) {
         this.checkPerm(PERM.PERM_VIEW_DISCUSSION);
         if (did) {
-            did = new ObjectID(did);
             this.ddoc = await discussion.get(domainId, did);
             if (!this.ddoc) throw new DiscussionNotFoundError(did);
             type = discussion.typeDisplay[this.ddoc.parentType];
-            name = this.ddoc.parentId;
-            if (drid) {
-                drid = new ObjectID(drid);
+            name = this.ddoc.parentId.toString();
+            if (drrid) {
+                [this.drdoc, this.drrdoc] = await discussion.getTailReply(domainId, drid, drrid);
+                if (!this.drrdoc) throw new DiscussionNotFoundError(drrid);
+            } else if (drid) {
                 this.drdoc = await discussion.getReply(domainId, drid);
                 if (!this.drdoc) throw new DiscussionNotFoundError(drid);
                 if (!this.drdoc.parentId.equals(this.ddoc._id)) {
                     throw new DocumentNotFoundError(drid);
                 }
-                if (drrid) {
-                    drrid = new ObjectID(drrid);
-                    [, this.drrdoc] = await discussion.getTailReply(domainId, drid, drrid);
-                    if (!this.drrdoc) throw new DiscussionNotFoundError(drrid);
-                    if (!this.drrdoc.parentId.equals(this.drdoc._id)) {
-                        throw new DocumentNotFoundError(drid);
-                    }
-                }
             }
         }
         // TODO(twd2): do more visibility check eg. contest
         // TODO(twd2): exclude problem/contest discussions?
         // TODO(iceboy): continuation based pagination.
-        if (ObjectID.isValid(name.toString())) name = new ObjectID(name);
-        this.vnode = await discussion.getVnode(domainId, typeMapper[type], name, this);
+        this.vnode = await discussion.getVnode(domainId, typeMapper[type], name);
+        if (this.vnode.hidden) this.checkPerm(PERM.PERM_VIEW_PROBLEM_HIDDEN);
         if (this.ddoc) {
             this.ddoc.parentType = this.ddoc.parentType || this.vnode.type;
             this.ddoc.parentId = this.ddoc.parentId || this.vnode.id;
@@ -76,7 +76,7 @@ class DiscussionMainHandler extends Handler {
         const [ddocs, dpcount] = await paginate(
             discussion.getMulti(domainId),
             page,
-            await system.get('DISCUSSION_PER_PAGE'),
+            CONSTANT.DISCUSSION_PER_PAGE,
         );
         const udict = await user.getList(domainId, ddocs.map((ddoc) => ddoc.owner));
         const path = [
@@ -84,7 +84,9 @@ class DiscussionMainHandler extends Handler {
             ['discussion_main', null],
         ];
         const [vndict, vnodes] = await Promise.all([
-            discussion.getListVnodes(domainId, ddocs, this),
+            discussion.getListVnodes(
+                domainId, ddocs, this.user.hasPerm(PERM.PERM_VIEW_PROBLEM_HIDDEN),
+            ),
             discussion.getNodes(domainId),
         ]);
         this.response.template = 'discussion_main_or_node.html';
@@ -106,7 +108,7 @@ class DiscussionNodeHandler extends DiscussionHandler {
         const [ddocs, dpcount] = await paginate(
             discussion.getMulti(domainId, { parentType: typeMapper[type], parentId: name }),
             page,
-            await system.get('DISCUSSION_PER_PAGE'),
+            CONSTANT.DISCUSSION_PER_PAGE,
         );
         const uids = ddocs.map((ddoc) => ddoc.owner);
         uids.push(this.vnode.owner);
@@ -152,9 +154,10 @@ class DiscussionCreateHandler extends DiscussionHandler {
     @param('title', Types.String, isTitle)
     @param('content', Types.String, isContent)
     @param('highlight', Types.Boolean)
+    @param('pin', Types.Boolean)
     async post(
         domainId: string, type: string, _name: string,
-        title: string, content: string, highlight = false,
+        title: string, content: string, highlight = false, pin = false,
     ) {
         this.limitRate('add_discussion', 3600, 30);
         let name: ObjectID | string | number;
@@ -162,9 +165,10 @@ class DiscussionCreateHandler extends DiscussionHandler {
         else if (isSafeInteger(parseInt(_name, 10))) name = parseInt(_name, 10);
         else name = _name;
         if (highlight) this.checkPerm(PERM.PERM_HIGHLIGHT_DISCUSSION);
+        if (pin) this.checkPerm(PERM.PERM_PIN_DISCUSSION);
         const did = await discussion.add(
             domainId, typeMapper[type], name, this.user._id,
-            title, content, this.request.ip, highlight,
+            title, content, this.request.ip, highlight, pin,
         );
         this.response.body = { did };
         this.response.redirect = this.url('discussion_detail', { did });
@@ -181,7 +185,7 @@ class DiscussionDetailHandler extends DiscussionHandler {
         const [drdocs, pcount, drcount] = await paginate(
             discussion.getMultiReply(domainId, did),
             page,
-            await system.get('REPLY_PER_PAGE'),
+            CONSTANT.REPLY_PER_PAGE,
         );
         const uids = drdocs.map((drdoc) => drdoc.owner);
         uids.push(this.ddoc.owner);
@@ -327,13 +331,16 @@ class DiscussionEditHandler extends DiscussionHandler {
     @param('title', Types.String, isTitle)
     @param('content', Types.String, isContent)
     @param('highlight', Types.Boolean)
+    @param('pin', Types.Boolean)
     async postUpdate(
-        domainId: string, did: ObjectID, title: string, content: string, highlight = false,
+        domainId: string, did: ObjectID, title: string, content: string,
+        highlight = false, pin = false,
     ) {
         if (this.ddoc.owner !== this.user._id) this.checkPerm(PERM.PERM_EDIT_DISCUSSION);
         else this.checkPerm(PERM.PERM_EDIT_DISCUSSION_SELF);
-        if (highlight && !this.ddoc.highlight) this.checkPerm(PERM.PERM_HIGHLIGHT_DISCUSSION);
-        await discussion.edit(domainId, did, title, content, highlight);
+        if (highlight !== this.ddoc.highlight) this.checkPerm(PERM.PERM_HIGHLIGHT_DISCUSSION);
+        if (pin !== this.ddoc.pin) this.checkPerm(PERM.PERM_PIN_DISCUSSION);
+        await discussion.edit(domainId, did, title, content, highlight, pin);
         this.response.body = { did };
         this.response.redirect = this.url('discussion_detail', { did });
     }
diff --git a/hydro/handler/home.ts b/hydro/handler/home.ts
index be1ffe98d..7712c1105 100644
--- a/hydro/handler/home.ts
+++ b/hydro/handler/home.ts
@@ -21,7 +21,7 @@ import * as domain from '../model/domain';
 import * as discussion from '../model/discussion';
 import * as token from '../model/token';
 import * as training from '../model/training';
-import { PERM, PRIV } from '../model/builtin';
+import { PERM, PRIV, CONSTANT } from '../model/builtin';
 import {
     isContent, isPassword, isEmail, isTitle,
 } from '../lib/validator';
@@ -33,7 +33,7 @@ class HomeHandler extends Handler {
         if (this.user.hasPerm(PERM.PERM_VIEW_HOMEWORK)) {
             const tdocs = await contest.getMulti(domainId, {}, document.TYPE_HOMEWORK)
                 .sort('beginAt', -1)
-                .limit(await system.get('HOMEWORK_ON_MAIN'))
+                .limit(CONSTANT.HOMEWORK_ON_MAIN)
                 .toArray();
             const tsdict = await contest.getListStatus(
                 domainId, this.user._id,
@@ -48,7 +48,7 @@ class HomeHandler extends Handler {
         if (this.user.hasPerm(PERM.PERM_VIEW_CONTEST)) {
             const tdocs = await contest.getMulti(domainId)
                 .sort('beginAt', -1)
-                .limit(await system.get('CONTEST_ON_MAIN'))
+                .limit(CONSTANT.CONTEST_ON_MAIN)
                 .toArray();
             const tsdict = await contest.getListStatus(
                 domainId, this.user._id, tdocs.map((tdoc) => tdoc.docId),
@@ -62,7 +62,7 @@ class HomeHandler extends Handler {
         if (this.user.hasPerm(PERM.PERM_VIEW_TRAINING)) {
             const tdocs = await training.getMulti(domainId)
                 .sort('_id', 1)
-                .limit(await system.get('TRAINING_ON_MAIN'))
+                .limit(CONSTANT.TRAINING_ON_MAIN)
                 .toArray();
             const tsdict = await training.getListStatus(
                 domainId, this.user._id, tdocs.map((tdoc) => tdoc.docId),
@@ -75,9 +75,11 @@ class HomeHandler extends Handler {
     async discussion(domainId: string): Promise<[any[], any]> {
         if (this.user.hasPerm(PERM.PERM_VIEW_DISCUSSION)) {
             const ddocs = await discussion.getMulti(domainId)
-                .limit(await system.get('DISCUSSION_ON_MAIN'))
+                .limit(CONSTANT.DISCUSSION_ON_MAIN)
                 .toArray();
-            const vndict = await discussion.getListVnodes(domainId, ddocs, this);
+            const vndict = await discussion.getListVnodes(
+                domainId, ddocs, this.user.hasPerm(PERM.PERM_VIEW_PROBLEM_HIDDEN),
+            );
             return [ddocs, vndict];
         }
         return [[], {}];
diff --git a/hydro/handler/homework.ts b/hydro/handler/homework.ts
index 206628e5d..a4bb9a6cf 100644
--- a/hydro/handler/homework.ts
+++ b/hydro/handler/homework.ts
@@ -12,8 +12,7 @@ import {
     Route, Handler, Types, param,
 } from '../service/server';
 import * as bus from '../service/bus';
-import { PERM } from '../model/builtin';
-import * as system from '../model/system';
+import { PERM, CONSTANT } from '../model/builtin';
 import * as user from '../model/user';
 import * as contest from '../model/contest';
 import * as discussion from '../model/discussion';
@@ -84,7 +83,7 @@ class HomeworkDetailHandler extends HomeworkHandler {
         const [ddocs, dpcount, dcount] = await paginate(
             discussion.getMulti(domainId, { parentType: tdoc.docType, parentId: tdoc.docId }),
             page,
-            await system.get('DISCUSSION_PER_PAGE'),
+            CONSTANT.DISCUSSION_PER_PAGE,
         );
         const uids = ddocs.map((ddoc) => ddoc.owner);
         uids.push(tdoc.owner);
diff --git a/hydro/handler/misc.ts b/hydro/handler/misc.ts
index 217ab9756..29d29a431 100644
--- a/hydro/handler/misc.ts
+++ b/hydro/handler/misc.ts
@@ -102,34 +102,6 @@ class SwitchLanguageHandler extends Handler {
     }
 }
 
-class UiSettingsHandler extends Handler {
-    async get() {
-        const [
-            header_logo, header_logo_2x,
-            nav_logo_dark, nav_logo_light,
-            nav_logo_dark_2x, nav_logo_light_2x,
-            header_background, header_background_2x,
-        ] = await system.getMany([
-            'ui.header_logo', 'ui.header_logo_2x',
-            'ui.nav_logo_dark', 'ui.nav_logo_light',
-            'ui.nav_logo_dark_2x', 'ui.nav_logo_light_2x',
-            'ui.header_background', 'ui.header_background2x',
-        ]);
-        this.response.body = await this.renderHTML('extra.css', {
-            header_logo,
-            header_logo_2x,
-            nav_logo_dark,
-            nav_logo_light,
-            nav_logo_dark_2x,
-            nav_logo_light_2x,
-            header_background,
-            header_background_2x,
-        });
-        this.response.type = 'text/css';
-        this.ctx.set('nolog', '1');
-    }
-}
-
 export async function apply() {
     Route('file_download', '/fs/:fileId/:secret', FileDownloadHandler);
     Route('file_download_with_name', '/fs/:fileId/:name/:secret', FileDownloadHandler);
@@ -137,7 +109,6 @@ export async function apply() {
     Route('status', '/status', StatusHandler);
     Route('status_update', '/status/update', StatusUpdateHandler);
     Route('switch_language', '/language/:lang', SwitchLanguageHandler);
-    Route('ui', '/extra.css', UiSettingsHandler);
 }
 
 global.Hydro.handler.misc = apply;
diff --git a/hydro/handler/problem.ts b/hydro/handler/problem.ts
index bf09d42d5..5294b2247 100644
--- a/hydro/handler/problem.ts
+++ b/hydro/handler/problem.ts
@@ -19,8 +19,7 @@ import * as record from '../model/record';
 import * as domain from '../model/domain';
 import * as user from '../model/user';
 import * as solution from '../model/solution';
-import * as system from '../model/system';
-import { PERM, PRIV } from '../model/builtin';
+import { PERM, PRIV, CONSTANT } from '../model/builtin';
 import * as bus from '../service/bus';
 import {
     Route, Connection, Handler, ConnectionHandler, Types, param, multipart,
@@ -78,7 +77,7 @@ class ProblemMainHandler extends ProblemHandler {
         const [pdocs, ppcount, pcount] = await paginate(
             problem.getMulti(domainId, query).sort({ pid: 1 }),
             page,
-            await system.get('PROBLEM_PER_PAGE'),
+            CONSTANT.PROBLEM_PER_PAGE,
         );
         if (this.user.hasPriv(PRIV.PRIV_USER_PROFILE)) {
             psdict = await problem.getListStatus(
@@ -122,7 +121,7 @@ class ProblemCategoryHandler extends ProblemHandler {
         const [pdocs, ppcount, pcount] = await paginate(
             problem.getMulti(domainId, q).sort({ pid: 1 }),
             page,
-            await system.get('PROBLEM_PER_PAGE'),
+            CONSTANT.PROBLEM_PER_PAGE,
         );
         if (this.user.hasPriv(PRIV.PRIV_USER_PROFILE)) {
             psdict = await problem.getListStatus(
@@ -466,7 +465,7 @@ class ProblemSolutionHandler extends ProblemDetailHandler {
         const [psdocs, pcount, pscount] = await paginate(
             solution.getMulti(domainId, this.pdoc.docId),
             page,
-            await system.get('SOLUTION_PER_PAGE'),
+            CONSTANT.SOLUTION_PER_PAGE,
         );
         const uids = [this.pdoc.owner];
         const docids = [];
diff --git a/hydro/handler/record.ts b/hydro/handler/record.ts
index c1563d7bf..1e91d65f1 100644
--- a/hydro/handler/record.ts
+++ b/hydro/handler/record.ts
@@ -1,10 +1,9 @@
 import { ObjectID } from 'mongodb';
 import { PermissionError, RecordNotFoundError } from '../error';
-import { PERM } from '../model/builtin';
+import { PERM, CONSTANT } from '../model/builtin';
 import * as problem from '../model/problem';
 import * as record from '../model/record';
 import * as contest from '../model/contest';
-import * as system from '../model/system';
 import * as user from '../model/user';
 import paginate from '../lib/paginate';
 import * as bus from '../service/bus';
@@ -34,7 +33,7 @@ class RecordListHandler extends RecordHandler {
         const [rdocs] = await paginate(
             record.getMulti(domainId, q).sort('_id', -1),
             page,
-            await system.get('RECORD_PER_PAGE'),
+            CONSTANT.RECORD_PER_PAGE,
         );
         const canViewProblemHidden = this.user.hasPerm(PERM.PERM_VIEW_PROBLEM_HIDDEN);
         const [udict, pdict] = await Promise.all([
diff --git a/hydro/handler/training.ts b/hydro/handler/training.ts
index d8a821f1e..f0426e1ba 100644
--- a/hydro/handler/training.ts
+++ b/hydro/handler/training.ts
@@ -3,12 +3,11 @@ import { ObjectID } from 'mongodb';
 import { ValidationError, ProblemNotFoundError } from '../error';
 import { isTitle, isContent, isDescription } from '../lib/validator';
 import paginate from '../lib/paginate';
-import { PERM, PRIV } from '../model/builtin';
+import { PERM, PRIV, CONSTANT } from '../model/builtin';
 import * as problem from '../model/problem';
 import * as builtin from '../model/builtin';
 import * as training from '../model/training';
 import * as user from '../model/user';
-import * as system from '../model/system';
 import {
     Route, Handler, Types, param,
 } from '../service/server';
@@ -58,9 +57,9 @@ class TrainingMainHandler extends Handler {
     @param('page', Types.UnsignedInt, true)
     async get(domainId: string, page = 1) {
         const [tdocs, tpcount] = await paginate(
-            training.getMulti(domainId).sort('_id', 1),
+            training.getMulti(domainId),
             page,
-            await system.get('TRAINING_PER_PAGE'),
+            CONSTANT.TRAINING_PER_PAGE,
         );
         const tids: Set<ObjectID> = new Set();
         for (const tdoc of tdocs) tids.add(tdoc.docId);
diff --git a/hydro/interface.ts b/hydro/interface.ts
index 16fa9ac44..c7a13bd96 100644
--- a/hydro/interface.ts
+++ b/hydro/interface.ts
@@ -231,6 +231,7 @@ export interface DomainDoc extends Dictionary<any> {
     roles: Dictionary<string>,
     gravatar: string,
     bulletin: string,
+    pidCounter: number,
 }
 
 // Message
@@ -262,10 +263,14 @@ export interface Ddoc {
     _id: ObjectID,
     docType: number,
     docId: ObjectID,
+    parentType: number,
+    parentId: ObjectID | number,
     owner: number,
     title: string,
     content: string,
     ip: string,
+    pin: boolean,
+    highlight: boolean,
 }
 
 // Discussion reply
@@ -277,6 +282,7 @@ export interface Drdoc {
     parentId: ObjectID,
     owner: number,
     ip: string,
+    content: string,
     reply: Drrdoc[],
 }
 
diff --git a/hydro/model/builtin.ts b/hydro/model/builtin.ts
index 0b031855e..0598fd0be 100644
--- a/hydro/model/builtin.ts
+++ b/hydro/model/builtin.ts
@@ -46,6 +46,7 @@ export const PERM = {
     PERM_VIEW_DISCUSSION: 1n << 27n,
     PERM_CREATE_DISCUSSION: 1n << 28n,
     PERM_HIGHLIGHT_DISCUSSION: 1n << 29n,
+    PERM_PIN_DISCUSSION: 1n << 59n,
     PERM_EDIT_DISCUSSION: 1n << 30n,
     PERM_EDIT_DISCUSSION_SELF: 1n << 31n,
     PERM_DELETE_DISCUSSION: 1n << 32n,
@@ -603,6 +604,20 @@ export const USER_GENDER_ICONS = {
     [USER_GENDER_OTHER]: '?',
 };
 
+export const CONSTANT = {
+    PROBLEM_PER_PAGE: 100,
+    CONTEST_PER_PAGE: 20,
+    DISCUSSION_PER_PAGE: 50,
+    RECORD_PER_PAGE: 100,
+    SOLUTION_PER_PAGE: 20,
+    TRAINING_PER_PAGE: 10,
+    REPLY_PER_PAGE: 50,
+    HOMEWORK_ON_MAIN: 5,
+    DISCUSSION_ON_MAIN: 20,
+    CONTEST_ON_MAIN: 10,
+    TRAINING_ON_MAIN: 10,
+};
+
 global.Hydro.model.builtin = {
     Permission,
     PERM,
diff --git a/hydro/model/discussion.ts b/hydro/model/discussion.ts
index 1c569f9a7..cf42cd3f5 100644
--- a/hydro/model/discussion.ts
+++ b/hydro/model/discussion.ts
@@ -3,7 +3,6 @@ import * as problem from './problem';
 import * as contest from './contest';
 import * as training from './training';
 import * as document from './document';
-import { PERM } from './builtin';
 import { DocumentNotFoundError } from '../error';
 import { Ddoc, Drdoc, Drrdoc } from '../interface';
 
@@ -18,7 +17,7 @@ export const typeDisplay = {
 export function add(
     domainId: string, parentType: number, parentId: ObjectID | number | string,
     owner: number, title: string, content: string,
-    ip: string | null = null, highlight: boolean = false,
+    ip: string | null = null, highlight: boolean, pin: boolean,
 ): Promise<ObjectID> {
     return document.add(
         domainId, content, owner, document.TYPE_DISCUSSION,
@@ -26,8 +25,9 @@ export function add(
         {
             title,
             ip,
-            highlight,
             nReply: 0,
+            highlight,
+            pin,
             updateAt: new Date(),
             views: 0,
         },
@@ -40,9 +40,11 @@ export function get(domainId: string, did: ObjectID): Promise<Ddoc | null> {
 
 export function edit(
     domainId: string, did: ObjectID,
-    title: string, content: string, highlight: boolean,
+    title: string, content: string, highlight: boolean, pin: boolean,
 ): Promise<Ddoc | null> {
-    return document.set(domainId, document.TYPE_DISCUSSION, did, { title, content, highlight });
+    return document.set(domainId, document.TYPE_DISCUSSION, did, {
+        title, content, highlight, pin,
+    });
 }
 
 export function del(domainId: string, did: ObjectID) {
@@ -60,7 +62,8 @@ export function count(domainId: string, query: any) {
 }
 
 export function getMulti(domainId: string, query: any = {}) {
-    return document.getMulti(domainId, document.TYPE_DISCUSSION, query).sort('updateAt', -1);
+    return document.getMulti(domainId, document.TYPE_DISCUSSION, query)
+        .sort({ pin: -1, updateAt: -1 });
 }
 
 export async function addReply(
@@ -158,13 +161,12 @@ export function getNode(domainId: string, _id: string) {
     return document.get(domainId, document.TYPE_DISCUSSION_NODE, _id);
 }
 
-export async function getVnode(domainId: string, type: number, id: string, handler: any) {
+export async function getVnode(domainId: string, type: number, id: string) {
     if (type === document.TYPE_PROBLEM) {
         // @ts-ignore
         if (Number.isSafeInteger(parseInt(id, 10))) id = parseInt(id, 10);
         const pdoc = await problem.get(domainId, id);
         if (!pdoc) return null;
-        if (pdoc.hidden && handler) handler.checkPerm(PERM.PERM_VIEW_PROBLEM_HIDDEN);
         return { ...pdoc, type, id };
     }
     if (type === document.TYPE_CONTEST) {
@@ -199,12 +201,13 @@ export function getNodes(domainId: string) {
     return document.getMulti(domainId, document.TYPE_DISCUSSION_NODE).toArray();
 }
 
-export async function getListVnodes(domainId: string, ddocs: any, handler: any) {
+export async function getListVnodes(domainId: string, ddocs: any, getHidden: boolean) {
     const tasks = [];
     const res = {};
-    async function task(ddoc) {
-        const vnode = await getVnode(domainId, ddoc.parentType, ddoc.parentId, handler);
+    async function task(ddoc: Ddoc) {
+        const vnode = await getVnode(domainId, ddoc.parentType, ddoc.parentId.toString());
         if (!res[ddoc.parentType]) res[ddoc.parentType] = {};
+        if (vnode.hidden && !getHidden) return;
         res[ddoc.parentType][ddoc.parentId] = vnode;
     }
     for (const ddoc of ddocs) tasks.push(task(ddoc));
diff --git a/hydro/model/document.ts b/hydro/model/document.ts
index 571ff90f5..3dd5502fa 100644
--- a/hydro/model/document.ts
+++ b/hydro/model/document.ts
@@ -328,66 +328,40 @@ export async function revSetStatus(
     return await collStatus.updateOne(filter, update);
 }
 
+/* eslint-disable object-curly-newline */
 async function ensureIndexes() {
-    await coll.createIndex({ domainId: 1, docType: 1, docId: 1 }, { unique: true });
-    await coll.createIndex({
-        domainId: 1, docType: 1, owner: 1, docId: -1,
-    });
+    const ic = coll.createIndex.bind(coll);
+    const is = collStatus.createIndex.bind(coll);
+    const u = { unique: true };
+    const s = { sparse: true };
+    await ic({ domainId: 1, docType: 1, docId: 1 }, u);
+    await ic({ domainId: 1, docType: 1, owner: 1, docId: -1 });
     // For problem
-    await coll.createIndex({
-        domainId: 1, docType: 1, category: 1, docId: 1,
-    }, { sparse: true });
-    await coll.createIndex({
-        domainId: 1, docType: 1, hidden: 1, category: 1, docId: 1,
-    }, { sparse: true });
-    await coll.createIndex({
-        domainId: 1, docType: 1, tag: 1, docId: 1,
-    }, { sparse: true });
-    await coll.createIndex({
-        domainId: 1, docType: 1, hidden: 1, tag: 1, docId: 1,
-    }, { sparse: true });
+    await ic({ domainId: 1, docType: 1, category: 1, docId: 1 }, s);
+    await ic({ domainId: 1, docType: 1, hidden: 1, category: 1, docId: 1 }, s);
+    await ic({ domainId: 1, docType: 1, tag: 1, docId: 1 }, s);
+    await ic({ domainId: 1, docType: 1, hidden: 1, tag: 1, docId: 1 }, s);
     // For problem solution
-    await coll.createIndex({
-        domainId: 1, docType: 1, parentType: 1, parentId: 1, vote: -1, docId: -1,
-    }, { sparse: true });
+    await ic({ domainId: 1, docType: 1, parentType: 1, parentId: 1, vote: -1, docId: -1 }, s);
     // For discussion
-    await coll.createIndex({
-        domainId: 1, docType: 1, updateAt: -1, docId: -1,
-    }, { sparse: true });
-    await coll.createIndex({
-        domainId: 1, docType: 1, parentType: 1, parentId: 1, updateAt: -1, docId: -1,
-    }, { sparse: true });
+    await ic({ domainId: 1, docType: 1, pin: -1, updateAt: -1, docId: -1 }, s);
+    await ic({ domainId: 1, docType: 1, parentType: 1, parentId: 1, updateAt: -1, docId: -1 }, s);
     // Hidden doc
-    await coll.createIndex({
-        domainId: 1, docType: 1, hidden: 1, docId: -1,
-    }, { sparse: true });
+    await ic({ domainId: 1, docType: 1, hidden: 1, docId: -1 }, s);
     // For contest
-    await coll.createIndex({ domainId: 1, docType: 1, pids: 1 }, { sparse: true });
-    await coll.createIndex({
-        domainId: 1, docType: 1, rule: 1, docId: -1,
-    }, { sparse: true });
+    await ic({ domainId: 1, docType: 1, pids: 1 }, s);
+    await ic({ domainId: 1, docType: 1, rule: 1, docId: -1 }, s);
     // For training
-    await coll.createIndex({ domainId: 1, docType: 1, 'dag.pids': 1 }, { sparse: true });
-
-    await collStatus.createIndex({
-        domainId: 1, docType: 1, uid: 1, docId: 1,
-    }, { unique: true });
+    await ic({ domainId: 1, docType: 1, 'dag.pids': 1 }, s);
+    await is({ domainId: 1, docType: 1, uid: 1, docId: 1 }, u);
     // For rp system
-    await collStatus.createIndex({
-        domainId: 1, docType: 1, docId: 1, status: 1, rid: 1, rp: 1,
-    }, { sparse: true });
+    await is({ domainId: 1, docType: 1, docId: 1, status: 1, rid: 1, rp: 1 }, s);
     // For contest rule OI
-    await collStatus.createIndex({
-        domainId: 1, docType: 1, docId: 1, score: -1,
-    }, { sparse: true });
+    await is({ domainId: 1, docType: 1, docId: 1, score: -1 }, s);
     // For contest rule ACM
-    await collStatus.createIndex({
-        domainId: 1, docType: 1, docId: 1, accept: -1, time: 1,
-    }, { sparse: true });
+    await is({ domainId: 1, docType: 1, docId: 1, accept: -1, time: 1 }, s);
     // For training
-    await collStatus.createIndex({
-        domainId: 1, docType: 1, uid: 1, enroll: 1, docId: 1,
-    }, { sparse: true });
+    await is({ domainId: 1, docType: 1, uid: 1, enroll: 1, docId: 1 }, s);
 }
 
 global.Hydro.postInit.push(ensureIndexes);
diff --git a/hydro/model/domain.ts b/hydro/model/domain.ts
index 23148e0cb..147d01e64 100644
--- a/hydro/model/domain.ts
+++ b/hydro/model/domain.ts
@@ -7,9 +7,16 @@ const coll = db.collection('domain');
 const collUser = db.collection('domain.user');
 
 export async function add(domainId: string, owner: number, name: string, bulletin: string) {
-    await coll.insertOne({
-        _id: domainId, owner, name, bulletin, roles: {},
-    });
+    const ddoc: DomainDoc = {
+        _id: domainId,
+        owner,
+        name,
+        bulletin,
+        roles: {},
+        gravatar: '',
+        pidCounter: 0,
+    };
+    await coll.insertOne(ddoc);
     return domainId;
 }
 
@@ -17,11 +24,6 @@ export function get(domainId: string): Promise<DomainDoc | null> {
     return coll.findOne({ _id: domainId });
 }
 
-export function getMany(query: any, sort: any, page: number, limit: number): Promise<DomainDoc[]> {
-    return coll.find(query).sort(sort).skip((page - 1) * limit).limit(limit)
-        .toArray();
-}
-
 export function getMulti(query: any = {}) {
     return coll.find(query);
 }
@@ -36,7 +38,7 @@ export async function inc(domainId: string, field: string, n: number): Promise<n
         { $inc: { [field]: n } },
         { returnOriginal: false },
     );
-    return res.value.field;
+    return res.value[field];
 }
 
 export async function getList(domainIds: string[]): Promise<Dictionary<DomainDoc>> {
@@ -155,7 +157,6 @@ global.Hydro.model.domain = {
     add,
     inc,
     get,
-    getMany,
     edit,
     getMulti,
     getList,
diff --git a/hydro/model/setting.ts b/hydro/model/setting.ts
index 6345dee4f..c424e887a 100644
--- a/hydro/model/setting.ts
+++ b/hydro/model/setting.ts
@@ -134,17 +134,6 @@ SystemSetting(
     Setting('setting_oauth', 'oauth.googleappid', null, null, 'text', 'Google Oauth ClientID', null),
     Setting('setting_oauth', 'oauth.googlesecret', null, null, 'text', 'Google Oauth Secret', null, FLAG_SECRET),
     Setting('setting_proxy', 'proxy', null, null, 'text', 'Proxy Server URL'),
-    Setting('setting_storage', 'PROBLEM_PER_PAGE', null, 100, 'number', 'Problems per Page', null, FLAG_HIDDEN),
-    Setting('setting_storage', 'CONTEST_PER_PAGE', null, 20, 'number', 'Contests per Page', null, FLAG_HIDDEN),
-    Setting('setting_storage', 'DISCUSSION_PER_PAGE', null, 50, 'number', 'Discussion per Page', null, FLAG_HIDDEN),
-    Setting('setting_storage', 'RECORD_PER_PAGE', null, 100, 'number', 'Record per Page', null, FLAG_HIDDEN),
-    Setting('setting_storage', 'SOLUTION_PER_PAGE', null, 20, 'number', 'Solutions per Page', null, FLAG_HIDDEN),
-    Setting('setting_storage', 'TRAINING_PER_PAGE', null, 10, 'number', 'Training per Page', null, FLAG_HIDDEN),
-    Setting('setting_storage', 'REPLY_PER_PAGE', null, 50, 'number', 'Reply per Page', null, FLAG_HIDDEN),
-    Setting('setting_storage', 'HOMEWORK_ON_MAIN', null, 5, 'number', 'HOMEWORK_ON_MAIN', null, FLAG_HIDDEN),
-    Setting('setting_storage', 'DISCUSSION_ON_MAIN', null, 20, 'number', 'DISCUSSION_ON_MAIN', null, FLAG_HIDDEN),
-    Setting('setting_storage', 'CONTEST_ON_MAIN', null, 10, 'number', 'CONTEST_ON_MAIN', null, FLAG_HIDDEN),
-    Setting('setting_storage', 'TRAINING_ON_MAIN', null, 10, 'number', 'TRAINING_ON_MAIN', null, FLAG_HIDDEN),
     Setting('setting_storage', 'db.ver', null, 1, 'number', 'Database version', null, FLAG_DISABLED | FLAG_HIDDEN),
     Setting('setting_storage', 'user', null, 1, 'number', 'User Counter', null, FLAG_DISABLED | FLAG_HIDDEN),
 );
diff --git a/hydro/model/training.ts b/hydro/model/training.ts
index 8080d361a..64f3b8125 100644
--- a/hydro/model/training.ts
+++ b/hydro/model/training.ts
@@ -108,7 +108,7 @@ export async function getList(domainId: string, tids: ObjectID[]) {
 }
 
 export const getMulti = (domainId: string, query: any = {}) =>
-    document.getMulti(domainId, document.TYPE_TRAINING, query);
+    document.getMulti(domainId, document.TYPE_TRAINING, query).sort('_id', 1);
 
 global.Hydro.model.training = {
     getPids,
diff --git a/hydro/options.ts b/hydro/options.ts
index 54e9601d6..79d00673f 100644
--- a/hydro/options.ts
+++ b/hydro/options.ts
@@ -8,6 +8,7 @@ export default function load() {
     if (!fs.existsSync(f)) f = path.resolve(os.homedir(), '.config', 'hydro', 'config.json');
     if (!fs.existsSync(f)) f = path.resolve(os.homedir(), '.hydro', 'config.json');
     if (!fs.existsSync(f)) f = path.resolve('/config/config.json');
+    if (!fs.existsSync(f)) return null;
     let result: any = {};
     try {
         result = JSON.parse(fs.readFileSync(f).toString());
diff --git a/hydro/service/server.ts b/hydro/service/server.ts
index dda17ebd8..7f56b736d 100644
--- a/hydro/service/server.ts
+++ b/hydro/service/server.ts
@@ -745,7 +745,7 @@ export function Connection(
 // TODO use postInit?
 export async function start() {
     const port = await system.get('server.port');
-    if (!argv.debug) {
+    if (argv.debug) {
         app.use(morgan(':method :url :status :res[content-length] - :response-time ms', {
             skip: (req, res) => res.hasHeader('nolog'),
         }));
diff --git a/locales/zh_CN.yaml b/locales/zh_CN.yaml
index 17336880c..0df07cb59 100644
--- a/locales/zh_CN.yaml
+++ b/locales/zh_CN.yaml
@@ -524,7 +524,6 @@ Problem Solution: 题解列表
 Problem Tags Visibility: 题目标签可见性
 problem_create: 创建题目
 problem_detail: 题目详情
-problem_detail: 题目详情
 problem_edit: 编辑题目
 problem_import: 导入题目
 problem_main: 题库
diff --git a/package.json b/package.json
index be13aca78..2ee7e3dfc 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "hydrooj",
-  "version": "2.11.9",
+  "version": "2.12.0",
   "main": "dist/loader.js",
   "bin": "bin/hydrooj.js",
   "repository": "https://github.com/hydro-dev/Hydro.git",