diff --git a/packages/hydrojudge/src/hosts/hydro.ts b/packages/hydrojudge/src/hosts/hydro.ts
index a09cb5692..f0d24450e 100644
--- a/packages/hydrojudge/src/hosts/hydro.ts
+++ b/packages/hydrojudge/src/hosts/hydro.ts
@@ -58,7 +58,7 @@ class JudgeTask {
         this.stat.handle = new Date();
         this.tag = this.request.tag;
         this.type = this.request.type;
-        this.domainId = this.request.domainId;
+        this.domainId = this.request.pdomain;
         this.pid = this.request.pid.toString();
         this.rid = this.request.rid;
         this.lang = this.request.lang;
@@ -120,7 +120,6 @@ class JudgeTask {
     next(data, id?: number) {
         log.debug('Next: %d %o', id, data);
         data.key = 'next';
-        data.domainId = this.request.domainId;
         data.rid = new ObjectID(this.rid);
         if (data.time_ms) data.time = data.time_ms;
         if (data.memory_kb) data.memory = data.memory_kb;
@@ -162,7 +161,6 @@ class JudgeTask {
         log.info('End: %o', data);
         data.key = 'end';
         data.rid = new ObjectID(this.request.rid);
-        data.domainId = this.request.domainId;
         data.time = data.time_ms ?? data.time;
         data.memory = data.memory_kb ?? data.memory;
         this.ws.send(JSON.stringify(data));
diff --git a/packages/hydrojudge/src/service.ts b/packages/hydrojudge/src/service.ts
index 75e095878..18ea36f89 100644
--- a/packages/hydrojudge/src/service.ts
+++ b/packages/hydrojudge/src/service.ts
@@ -102,7 +102,6 @@ async function postInit() {
         that.nextWaiting = [];
         return (data, id = 0) => {
             logger.debug('Next: %d %o', id, data);
-            data.domainId = that.domainId;
             data.rid = new ObjectID(that.rid);
             if (data.time_ms) data.time = data.time_ms;
             if (data.memory_kb) data.memory = data.memory_kb;
@@ -139,11 +138,10 @@ async function postInit() {
         };
     }
 
-    function getEnd(domainId: string, rid: string) {
+    function getEnd(rid: string) {
         return (data) => {
             data.key = 'end';
             data.rid = new ObjectID(rid);
-            data.domainId = domainId;
             data.time = data.time_ms ?? data.time;
             data.memory = data.memory_kb ?? data.memory;
             logger.info('End: status=%d score=%d time=%dms memory=%dkb', data.status, data.score, data.time, data.memory);
@@ -188,14 +186,14 @@ async function postInit() {
                 this.stat.handle = new Date();
                 this.pid = (this.request.pid || 'unknown').toString();
                 this.rid = this.request.rid.toString();
-                this.domainId = this.request.domainId;
+                this.domainId = this.request.pdomain;
                 this.lang = this.request.lang;
                 this.code = this.request.code;
                 this.data = this.request.data;
                 this.config = this.request.config;
                 this.input = this.request.input;
                 this.next = getNext(this);
-                this.end = getEnd(this.domainId, this.rid);
+                this.end = getEnd(this.rid);
                 this.tmpdir = path.resolve(getConfig('tmp_dir'), this.rid);
                 this.clean = [];
                 fs.ensureDirSync(this.tmpdir);
diff --git a/packages/hydrooj/package.json b/packages/hydrooj/package.json
index bc0462b86..d40cd3ab1 100644
--- a/packages/hydrooj/package.json
+++ b/packages/hydrooj/package.json
@@ -1,6 +1,6 @@
 {
     "name": "hydrooj",
-    "version": "2.27.7",
+    "version": "2.28.0",
     "bin": "bin/hydrooj.js",
     "main": "dist/loader.js",
     "typings": "dist/loader.d.ts",
diff --git a/packages/hydrooj/src/handler/contest.ts b/packages/hydrooj/src/handler/contest.ts
index a2e448926..94b700950 100644
--- a/packages/hydrooj/src/handler/contest.ts
+++ b/packages/hydrooj/src/handler/contest.ts
@@ -1,11 +1,14 @@
 import moment from 'moment-timezone';
 import { ObjectID } from 'mongodb';
 import AdmZip from 'adm-zip';
+import { Time } from '@hydrooj/utils/lib/utils';
 import {
     ContestNotLiveError, ValidationError, ProblemNotFoundError,
     ContestNotAttendedError, PermissionError, BadRequestError,
 } from '../error';
-import { ProblemDoc, Tdoc, User } from '../interface';
+import {
+    ProblemId, ProblemDoc, Tdoc, User,
+} from '../interface';
 import paginate from '../lib/paginate';
 import { PERM, PRIV } from '../model/builtin';
 import * as contest from '../model/contest';
@@ -22,23 +25,13 @@ import {
 import * as bus from '../service/bus';
 import storage from '../service/storage';
 
-class ContestListHandler extends Handler {
+export class ContestListHandler extends Handler {
     @param('rule', Types.Range(contest.RULES), true)
     @param('page', Types.PositiveInt, true)
     async get(domainId: string, rule = '', page = 1) {
-        this.response.template = 'contest_main.html';
-        let tdocs;
-        let qs;
-        let tpcount;
-        if (!rule) {
-            tdocs = contest.getMulti(domainId).sort({ beginAt: -1 });
-            qs = '';
-        } else {
-            tdocs = contest.getMulti(domainId, { rule }).sort({ beginAt: -1 });
-            qs = `rule=${rule}`;
-        }
-        // eslint-disable-next-line prefer-const
-        [tdocs, tpcount] = await paginate(tdocs, page, system.get('pagination.contest'));
+        const cursor = contest.getMulti(domainId, rule ? { rule } : undefined).sort({ beginAt: -1 });
+        const qs = rule ? `rule=${rule}` : '';
+        const [tdocs, tpcount] = await paginate(cursor, page, system.get('pagination.contest'));
         const tids = [];
         for (const tdoc of tdocs) tids.push(tdoc.docId);
         const tsdict = await contest.getListStatus(domainId, this.user._id, tids);
@@ -46,13 +39,14 @@ class ContestListHandler extends Handler {
             ['Hydro', 'homepage'],
             ['contest_main', null],
         ];
+        this.response.template = 'contest_main.html';
         this.response.body = {
             page, tpcount, qs, rule, tdocs, tsdict, path,
         };
     }
 }
 
-class ContestDetailHandler extends Handler {
+export class ContestDetailHandler extends Handler {
     @param('tid', Types.ObjectID)
     @param('page', Types.PositiveInt, true)
     async get(domainId: string, tid: ObjectID, page = 1) {
@@ -165,42 +159,49 @@ class ContestScoreboardDownloadHandler extends Handler {
     }
 }
 
-class ContestEditHandler extends Handler {
+export class ContestEditHandler extends Handler {
     tdoc: Tdoc;
 
-    @param('tid', Types.ObjectID)
+    @param('tid', Types.ObjectID, true)
     async prepare(domainId: string, tid: ObjectID) {
-        this.tdoc = await contest.get(domainId, tid);
-        if (!this.user.own(this.tdoc)) this.checkPerm(PERM.PERM_EDIT_CONTEST);
-        else this.checkPerm(PERM.PERM_EDIT_CONTEST_SELF);
+        if (tid) {
+            this.tdoc = await contest.get(domainId, tid);
+            if (!this.user.own(this.tdoc)) this.checkPerm(PERM.PERM_EDIT_CONTEST);
+            else this.checkPerm(PERM.PERM_EDIT_CONTEST_SELF);
+        }
     }
 
-    async get() {
+    @param('tid', Types.ObjectID, true)
+    async get(domainId: string, tid: ObjectID) {
         this.response.template = 'contest_edit.html';
         const rules = {};
-        for (const i in contest.RULES) {
-            rules[i] = contest.RULES[i].TEXT;
-        }
-        const duration = (this.tdoc.endAt.getTime() - this.tdoc.beginAt.getTime()) / 3600 / 1000;
+        for (const i in contest.RULES) rules[i] = contest.RULES[i].TEXT;
         const path = [
             ['Hydro', 'homepage'],
             ['contest_main', 'contest_main'],
-            [this.tdoc.title, 'contest_detail', { tid: this.tdoc.docId }, true],
-            ['contest_edit', null],
+            ...tid
+                ? [
+                    [this.tdoc.title, 'contest_detail', { tid: this.tdoc.docId }, true],
+                    ['contest_edit', null],
+                ]
+                : [['contest_create', null]],
         ];
-        const dt = this.tdoc.beginAt;
+        let ts = new Date().getTime();
+        ts = ts - (ts % (15 * Time.minute)) + 15 * Time.minute;
+        const dt = this.tdoc?.beginAt || new Date(ts);
         this.response.body = {
             rules,
             tdoc: this.tdoc,
-            duration,
+            duration: tid ? (this.tdoc.endAt.getTime() - this.tdoc.beginAt.getTime()) / Time.hour : 2,
             path,
-            pids: this.tdoc.pids.join(','),
+            pids: tid ? this.tdoc.pids.join(',') : '',
             date_text: dt.format('%Y-%m-%d'),
             time_text: dt.format('%H:%M'),
-            page_name: 'contest_edit',
+            page_name: tid ? 'contest_edit' : 'contest_create',
         };
     }
 
+    @param('tid', Types.ObjectID, true)
     @param('beginAtDate', Types.Date)
     @param('beginAtTime', Types.Time)
     @param('duration', Types.Float)
@@ -210,31 +211,36 @@ class ContestEditHandler extends Handler {
     @param('pids', Types.Content)
     @param('rated', Types.Boolean)
     async post(
-        domainId: string, beginAtDate: string, beginAtTime: string, duration: number,
+        domainId: string, tid: ObjectID, beginAtDate: string, beginAtTime: string, duration: number,
         title: string, content: string, rule: string, _pids: string, rated = false,
     ) {
-        const pids = _pids.replace(/，/g, ',').split(',').map((i) => +i).filter((i) => i);
-        await problem.getList(domainId, pids, this.user.hasPerm(PERM.PERM_VIEW_PROBLEM_HIDDEN), true);
+        const pids = _pids.replace(/，/g, ',').split(',').map((i) => {
+            if ((+i).toString() === i) return +i;
+            return i;
+        }).filter((i) => i);
         const beginAtMoment = moment.tz(`${beginAtDate} ${beginAtTime}`, this.user.timeZone);
-        if (!beginAtMoment.isValid()) {
-            throw new ValidationError('beginAtDate', 'beginAtTime');
-        }
+        if (!beginAtMoment.isValid()) throw new ValidationError('beginAtDate', 'beginAtTime');
         const endAt = beginAtMoment.clone().add(duration, 'hours').toDate();
         if (beginAtMoment.isSameOrAfter(endAt)) throw new ValidationError('duration');
         const beginAt = beginAtMoment.toDate();
-        await contest.edit(domainId, this.tdoc.docId, {
-            title, content, rule, beginAt, endAt, pids, rated,
-        });
-        if (this.tdoc.beginAt !== beginAt || this.tdoc.endAt !== endAt
-            || Array.isDiff(this.tdoc.pids, pids) || this.tdoc.rule !== rule) {
-            await contest.recalcStatus(domainId, this.tdoc.docId);
+        await problem.getList(domainId, pids, this.user.hasPerm(PERM.PERM_VIEW_PROBLEM_HIDDEN), true);
+        if (tid) {
+            await contest.edit(domainId, tid, {
+                title, content, rule, beginAt, endAt, pids, rated,
+            });
+            if (this.tdoc.beginAt !== beginAt || this.tdoc.endAt !== endAt
+                || Array.isDiff(this.tdoc.pids, pids) || this.tdoc.rule !== rule) {
+                await contest.recalcStatus(domainId, this.tdoc.docId);
+            }
+        } else {
+            tid = await contest.add(domainId, title, content, this.user._id, rule, beginAt, endAt, pids, rated);
         }
-        this.response.body = { tid: this.tdoc.docId };
-        this.response.redirect = this.url('contest_detail', { tid: this.tdoc.docId });
+        this.response.body = { tid };
+        this.response.redirect = this.url('contest_detail', { tid });
     }
 }
 
-class ContestProblemHandler extends Handler {
+export class ContestProblemHandler extends Handler {
     tdoc: Tdoc<30 | 60>;
     pdoc: ProblemDoc;
     tsdoc: any;
@@ -242,25 +248,22 @@ class ContestProblemHandler extends Handler {
     attended: boolean;
 
     @param('tid', Types.ObjectID)
-    @param('pid', Types.UnsignedInt)
-    async _prepare(domainId: string, tid: ObjectID, pid: number) {
-        [this.tdoc, this.pdoc] = await Promise.all([
-            contest.get(domainId, tid),
+    @param('pid', Types.Name)
+    async _prepare(domainId: string, tid: ObjectID, pid: ProblemId) {
+        this.tdoc = await contest.get(domainId, tid);
+        if (!this.tdoc.pids.includes(pid)) throw new ProblemNotFoundError(domainId, pid);
+        [this.pdoc, this.tsdoc, this.udoc] = await Promise.all([
             problem.get(domainId, pid),
-        ]);
-        [this.tsdoc, this.udoc] = await Promise.all([
-            contest.getStatus(domainId, this.tdoc.docId, this.user._id),
+            contest.getStatus(domainId, tid, this.user._id),
             user.getById(domainId, this.tdoc.owner),
         ]);
+        if (!this.pdoc) throw new ProblemNotFoundError(domainId, pid);
+        // @ts-ignore
+        if (this.pdoc.domainId !== domainId) this.pdoc.docId = `${this.pdoc.domainId}:${this.pdoc.docId}`;
         this.attended = this.tsdoc && this.tsdoc.attend === 1;
+        if (contest.isNotStarted(this.tdoc)) throw new ContestNotLiveError(tid);
+        if (!contest.isDone(this.tdoc) && !this.attended) throw new ContestNotAttendedError(tid);
         this.response.template = 'problem_detail.html';
-        if (!contest.isDone(this.tdoc)) {
-            if (!this.attended) throw new ContestNotAttendedError(this.tdoc.docId);
-            if (contest.isNotStarted(this.tdoc)) throw new ContestNotLiveError(this.tdoc.docId);
-        }
-        if (!this.tdoc.pids.map((s) => s.toString()).includes(this.pdoc.docId.toString())) {
-            throw new ProblemNotFoundError(domainId, this.tdoc.docId);
-        }
         this.response.body = {
             tdoc: this.tdoc,
             tsdoc: this.tsdoc,
@@ -271,18 +274,19 @@ class ContestProblemHandler extends Handler {
         };
     }
 
-    // eslint-disable-next-line
+    @param('tid', Types.ObjectID)
+    @param('pid', Types.Name)
     async get(...args: any[]) {
         this.response.body.path = [
             ['Hydro', 'homepage'],
             ['contest_main', 'contest_main'],
-            [this.tdoc.title, 'contest_detail', { tid: this.tdoc.docId }, true],
+            [this.tdoc.title, 'contest_detail', { tid: args[1] }, true],
             [this.pdoc.title, null, null, true],
         ];
         // Navigate to current additional file download
         // e.g. ![img](a.jpg) will navigate to ![img](./pid/file/a.jpg)
         this.response.body.pdoc.content = this.response.body.pdoc.content
-            .replace(/\(file:\/\//g, `(./${this.pdoc.docId}/file/`);
+            .replace(/\(file:\/\//g, `(./${args[2]}/file/`);
     }
 }
 
@@ -301,19 +305,19 @@ export class ContestProblemFileDownloadHandler extends ContestProblemHandler {
     }
 }
 
-class ContestDetailProblemSubmitHandler extends ContestProblemHandler {
+export class ContestDetailProblemSubmitHandler extends ContestProblemHandler {
     async prepare() {
         if (!contest.isOngoing(this.tdoc)) throw new ContestNotLiveError(this.tdoc.docId);
     }
 
     @param('tid', Types.ObjectID)
-    @param('pid', Types.UnsignedInt)
-    async get(domainId: string, tid: ObjectID, pid: number) {
+    @param('pid', Types.Name)
+    async get(domainId: string, tid: ObjectID, pid: ProblemId) {
         this.response.body.rdocs = [];
         if (contest.canShowRecord.call(this, this.tdoc)) {
             this.response.body.rdocs = await record.getUserInProblemMulti(
                 domainId, this.user._id,
-                this.pdoc.docId, true,
+                pid, { type: document.TYPE_CONTEST, tid },
             ).sort({ _id: -1 }).limit(10).toArray();
         }
         this.response.body.path = [
@@ -330,20 +334,21 @@ class ContestDetailProblemSubmitHandler extends ContestProblemHandler {
     @param('tid', Types.ObjectID)
     @param('lang', Types.Name)
     @param('code', Types.Content)
-    async post(domainId: string, tid: ObjectID, lang: string, code: string) {
+    @param('pid', Types.Name)
+    async post(domainId: string, tid: ObjectID, lang: string, code: string, pid: ProblemId) {
         if (this.response.body.pdoc.config?.langs && !this.response.body.pdoc.config.langs.includes(lang)) {
             throw new BadRequestError('Language not allowed.');
         }
         await this.limitRate('add_record', 60, 10);
-        const rid = await record.add(domainId, this.pdoc.docId, this.user._id, lang, code, true, {
+        const rid = await record.add(domainId, pid, this.user._id, lang, code, true, {
             type: document.TYPE_CONTEST,
             tid,
         });
         const [rdoc] = await Promise.all([
             record.get(domainId, rid),
-            problem.inc(domainId, this.pdoc.docId, 'nSubmit', 1),
+            problem.inc(domainId, pid, 'nSubmit', 1),
             domain.incUserInDomain(domainId, this.user._id, 'nSubmit'),
-            contest.updateStatus(domainId, this.tdoc.docId, this.user._id, rid, this.pdoc.docId),
+            contest.updateStatus(domainId, tid, this.user._id, rid, pid),
         ]);
         bus.boardcast('record/change', rdoc);
         if (!contest.canShowRecord.call(this, this.tdoc)) {
@@ -356,7 +361,7 @@ class ContestDetailProblemSubmitHandler extends ContestProblemHandler {
     }
 }
 
-class ContestCodeHandler extends Handler {
+export class ContestCodeHandler extends Handler {
     @param('tid', Types.ObjectID)
     async get(domainId: string, tid: ObjectID) {
         if (!this.user.hasPriv(PRIV.PRIV_READ_RECORD_CODE)) {
@@ -381,58 +386,8 @@ class ContestCodeHandler extends Handler {
     }
 }
 
-class ContestCreateHandler extends Handler {
-    async get() {
-        this.response.template = 'contest_edit.html';
-        const rules = {};
-        for (const i in contest.RULES) rules[i] = contest.RULES[i].TEXT;
-        const now = new Date();
-        let ts = now.getTime();
-        ts = ts - (ts % (15 * 60 * 1000)) + 15 * 60 * 1000;
-        const dt = new Date(ts);
-        const path = [
-            ['Hydro', 'homepage'],
-            ['contest_main', 'contest_main'],
-            ['contest_create', null],
-        ];
-        this.response.body = {
-            rules,
-            path,
-            page_name: 'contest_create',
-            date_text: dt.format('%Y-%m-%d'),
-            time_text: dt.format('%H:%M'),
-            pids: '1000, 1001',
-        };
-    }
-
-    @param('beginAtDate', Types.Date)
-    @param('beginAtTime', Types.Time)
-    @param('duration', Types.Float)
-    @param('title', Types.Title)
-    @param('content', Types.Content)
-    @param('rule', Types.Name)
-    @param('pids', Types.Content)
-    @param('rated', Types.Boolean)
-    async post(
-        domainId: string, beginAtDate: string, beginAtTime: string, duration: number,
-        title: string, content: string, rule: string, _pids: string, rated = false,
-    ) {
-        const pids = _pids.replace(/，/g, ',').split(',').map((i) => +i).filter((i) => i);
-        const beginAt = moment.tz(`${beginAtDate} ${beginAtTime}`, this.user.timeZone);
-        if (!beginAt.isValid()) throw new ValidationError('beginAtDate', 'beginAtTime');
-        const endAt = beginAt.clone().add(duration, 'hours').toDate();
-        await problem.getList(domainId, pids, this.user.hasPerm(PERM.PERM_VIEW_PROBLEM_HIDDEN), true);
-        const tid = await contest.add(
-            domainId, title, content,
-            this.user._id, rule, beginAt.toDate(), endAt, pids, rated,
-        );
-        this.response.body = { tid };
-        this.response.redirect = this.url('contest_detail', { tid });
-    }
-}
-
 export async function apply() {
-    Route('contest_create', '/contest/create', ContestCreateHandler, PERM.PERM_CREATE_CONTEST);
+    Route('contest_create', '/contest/create', ContestEditHandler, PERM.PERM_CREATE_CONTEST);
     Route('contest_main', '/contest', ContestListHandler, PERM.PERM_VIEW_CONTEST);
     Route('contest_detail', '/contest/:tid', ContestDetailHandler, PERM.PERM_VIEW_CONTEST);
     Route('contest_boardcast', '/contest/:tid/boardcast', ContestBoardcastHandler);
diff --git a/packages/hydrooj/src/handler/home.ts b/packages/hydrooj/src/handler/home.ts
index c80c329ba..64f6dc0db 100644
--- a/packages/hydrooj/src/handler/home.ts
+++ b/packages/hydrooj/src/handler/home.ts
@@ -11,7 +11,7 @@ import {
     Route, Connection, Handler, ConnectionHandler, param, Types,
 } from '../service/server';
 import { md5 } from '../lib/crypto';
-import { isPassword, isEmail } from '../lib/validator';
+import { isPassword, isEmail, isDomainId } from '../lib/validator';
 import avatar from '../lib/avatar';
 import * as mail from '../lib/mail';
 import * as contest from '../model/contest';
@@ -321,7 +321,7 @@ class HomeDomainCreateHandler extends Handler {
         this.response.template = 'domain_create.html';
     }
 
-    @param('id', Types.Name)
+    @param('id', Types.Name, isDomainId)
     @param('name', Types.Title)
     @param('bulletin', Types.Content)
     @param('avatar', Types.Content, true)
diff --git a/packages/hydrooj/src/handler/homework.ts b/packages/hydrooj/src/handler/homework.ts
index 01be9b319..d640a2710 100644
--- a/packages/hydrooj/src/handler/homework.ts
+++ b/packages/hydrooj/src/handler/homework.ts
@@ -2,13 +2,13 @@ import yaml from 'js-yaml';
 import moment from 'moment-timezone';
 import { ObjectID } from 'mongodb';
 import AdmZip from 'adm-zip';
+import { Time } from '@hydrooj/utils/lib/utils';
 import {
     ValidationError, HomeworkNotLiveError, ProblemNotFoundError,
-    HomeworkNotAttendedError,
-    BadRequestError,
+    HomeworkNotAttendedError, BadRequestError,
 } from '../error';
 import {
-    PenaltyRules, Tdoc, ProblemDoc, User,
+    PenaltyRules, Tdoc, ProblemDoc, User, ProblemId,
 } from '../interface';
 import {
     Route, Handler, Types, param,
@@ -24,11 +24,9 @@ import problem from '../model/problem';
 import record from '../model/record';
 import * as document from '../model/document';
 import paginate from '../lib/paginate';
+import { isExternalPid } from '../lib/validator';
 
-const validatePenaltyRules = (input: string) => {
-    const s = yaml.load(input);
-    return s;
-};
+const validatePenaltyRules = (input: string) => yaml.load(input);
 const convertPenaltyRules = validatePenaltyRules;
 
 class HomeworkMainHandler extends Handler {
@@ -40,9 +38,7 @@ class HomeworkMainHandler extends Handler {
             if (contest.isExtended(tdoc) || contest.isDone(tdoc)) {
                 cal.endAt = tdoc.endAt;
                 cal.penaltySince = tdoc.penaltySince;
-            } else {
-                cal.endAt = tdoc.penaltySince;
-            }
+            } else cal.endAt = tdoc.penaltySince;
             calendar.push(cal);
         }
         const path = [
@@ -126,12 +122,14 @@ class HomeworkDetailProblemHandler extends Handler {
     attended: boolean;
 
     @param('tid', Types.ObjectID)
-    @param('pid', Types.UnsignedInt)
-    async prepare(domainId: string, tid: ObjectID, pid: number) {
-        this.checkPerm(PERM.PERM_VIEW_PROBLEM);
+    @param('pid', Types.String, isExternalPid)
+    async _prepare(domainId: string, tid: ObjectID, pid: ProblemId) {
+        if (!this.tdoc.pids.includes(pid)) throw new ProblemNotFoundError(domainId, pid, tid);
+        const pdomainId = typeof pid === 'string' ? pid.split(':')[0] : domainId;
+        const ppid = typeof pid === 'number' ? pid : +pid.split(':')[1];
         [this.tdoc, this.pdoc, this.tsdoc] = await Promise.all([
             contest.get(domainId, tid, document.TYPE_HOMEWORK),
-            problem.get(domainId, pid),
+            problem.get(pdomainId, ppid),
             contest.getStatus(domainId, tid, this.user._id, document.TYPE_HOMEWORK),
         ]);
         this.udoc = await user.getById(domainId, this.tdoc.owner);
@@ -146,13 +144,13 @@ class HomeworkDetailProblemHandler extends Handler {
     }
 
     @param('tid', Types.ObjectID)
-    @param('pid', Types.UnsignedInt)
-    async get(domainId: string, tid: ObjectID, pid: number) {
+    @param('pid', Types.Name)
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    async get(domainId: string, tid: ObjectID, pid: ProblemId) {
         if (!contest.isDone(this.tdoc)) {
             if (!this.attended) throw new HomeworkNotAttendedError(tid);
             if (contest.isNotStarted(this.tdoc)) throw new HomeworkNotLiveError(tid);
         }
-        if (!this.tdoc.pids.includes(pid)) throw new ProblemNotFoundError(domainId, pid, tid);
         this.response.template = 'problem_detail.html';
         this.response.body.page_name = 'homework_detail_problem';
         this.response.body.path = [
@@ -166,13 +164,16 @@ class HomeworkDetailProblemHandler extends Handler {
 
 class HomeworkDetailProblemSubmitHandler extends HomeworkDetailProblemHandler {
     @param('tid', Types.ObjectID)
-    @param('pid', Types.UnsignedInt)
-    async get(domainId: string, tid: ObjectID, pid: number) {
+    async prepare(domainId: string, tid: ObjectID) {
         if (!this.attended) throw new HomeworkNotAttendedError(tid);
         if (!contest.isOngoing(this.tdoc)) throw new HomeworkNotLiveError(tid);
-        if (!this.tdoc.pids.includes(pid)) throw new ProblemNotFoundError(domainId, pid, tid);
+    }
+
+    @param('tid', Types.ObjectID)
+    @param('pid', Types.String, isExternalPid)
+    async get(domainId: string, tid: ObjectID, pid: ProblemId) {
         this.response.body.rdocs = contest.canShowRecord.call(this, this.tdoc)
-            ? await record.getUserInProblemMulti(domainId, this.user._id, pid, true)
+            ? await record.getUserInProblemMulti(domainId, this.user._id, pid, { type: document.TYPE_HOMEWORK, tid })
                 .sort('_id', -1).limit(10).toArray()
             : [];
         this.response.body.path = [
@@ -186,24 +187,23 @@ class HomeworkDetailProblemSubmitHandler extends HomeworkDetailProblemHandler {
     }
 
     @param('tid', Types.ObjectID)
-    @param('pid', Types.UnsignedInt)
+    @param('pid', Types.String, isExternalPid)
     @param('code', Types.Content)
     @param('lang', Types.Name)
-    async post(domainId: string, tid: ObjectID, pid: number, code: string, lang: string) {
+    async post(domainId: string, tid: ObjectID, pid: ProblemId, code: string, lang: string) {
         if (this.response.body.pdoc.config?.langs && !this.response.body.pdoc.config.langs.includes(lang)) {
             throw new BadRequestError('Language not allowed.');
         }
         await this.limitRate('add_record', 60, 5);
-        if (!this.attended) throw new HomeworkNotAttendedError(tid);
-        if (!contest.isOngoing(this.tdoc)) throw new HomeworkNotLiveError(tid);
-        if (!this.tdoc.pids.includes(pid)) throw new ProblemNotFoundError(domainId, pid);
         const rid = await record.add(domainId, pid, this.user._id, lang, code, true, {
             type: document.TYPE_HOMEWORK,
             tid,
         });
+        const pdomainId = typeof pid === 'string' ? pid.split(':')[0] : domainId;
+        const ppid = typeof pid === 'number' ? pid : +pid.split(':')[1];
         const [rdoc] = await Promise.all([
             record.get(domainId, rid),
-            problem.inc(domainId, pid, 'nSubmit', 1),
+            problem.inc(pdomainId, ppid, 'nSubmit', 1),
             domain.incUserInDomain(domainId, this.user._id, 'nSubmit'),
             contest.updateStatus(domainId, tid, this.user._id,
                 rid, pid, false, 0, document.TYPE_HOMEWORK),
@@ -216,77 +216,35 @@ class HomeworkDetailProblemSubmitHandler extends HomeworkDetailProblemHandler {
     }
 }
 
-class HomeworkCreateHandler extends Handler {
-    async get() {
-        const beginAt = moment().add(1, 'day');
-        const penaltySince = beginAt.clone().add(7, 'days');
-        const path = [
-            ['Hydro', 'homepage'],
-            ['homework_main', 'homework_main'],
-            ['homework_create', null],
-        ];
-        this.response.template = 'homework_edit.html';
-        this.response.body = {
-            path,
-            dateBeginText: beginAt.tz(this.user.timeZone).format('YYYY-M-D'),
-            timeBeginText: '00:00',
-            datePenaltyText: penaltySince.tz(this.user.timeZone).format('YYYY-M-D'),
-            timePenaltyText: '23:59',
-            pids: '1000, 1001',
-            extensionDays: 1,
-            page_name: 'homework_create',
-        };
-    }
-
-    @param('beginAtDate', Types.Date)
-    @param('beginAtTime', Types.Time)
-    @param('penaltySinceDate', Types.Date)
-    @param('penaltySinceTime', Types.Time)
-    @param('extensionDays', Types.Float)
-    @param('penaltyRules', Types.Content, validatePenaltyRules, convertPenaltyRules)
-    @param('title', Types.Title)
-    @param('content', Types.Content)
-    @param('pids', Types.Content)
-    @param('rated', Types.Boolean)
-    async post(
-        domainId: string, beginAtDate: string, beginAtTime: string,
-        penaltySinceDate: string, penaltySinceTime: string, extensionDays: number,
-        penaltyRules: PenaltyRules, title: string, content: string, _pids: string, rated = false,
-    ) {
-        const pids = _pids.replace(/，/g, ',').split(',').map((i) => +i).filter((i) => i);
-        const beginAt = moment.tz(`${beginAtDate} ${beginAtTime}`, this.user.timeZone);
-        if (!beginAt.isValid()) throw new ValidationError('beginAtDate', 'beginAtTime');
-        const penaltySince = moment.tz(`${penaltySinceDate} ${penaltySinceTime}`, this.user.timeZone);
-        if (!penaltySince.isValid()) throw new ValidationError('endAtDate', 'endAtTime');
-        const endAt = penaltySince.clone().add(extensionDays, 'days');
-        if (beginAt.isSameOrAfter(penaltySince)) throw new ValidationError('endAtDate', 'endAtTime');
-        if (penaltySince.isAfter(endAt)) throw new ValidationError('extensionDays');
-        await problem.getList(domainId, pids, this.user.hasPerm(PERM.PERM_VIEW_PROBLEM_HIDDEN), true);
-        const tid = await contest.add(domainId, title, content, this.user._id,
-            'homework', beginAt.toDate(), endAt.toDate(), pids, rated,
-            { penaltySince: penaltySince.toDate(), penaltyRules }, document.TYPE_HOMEWORK);
-        this.response.body = { tid };
-        this.response.redirect = this.url('homework_detail', { tid });
-    }
-}
-
 class HomeworkEditHandler extends Handler {
-    @param('tid', Types.ObjectID)
+    @param('tid', Types.ObjectID, true)
     async get(domainId: string, tid: ObjectID) {
-        const tdoc = await contest.get(domainId, tid, document.TYPE_HOMEWORK);
+        const tdoc = tid
+            ? await contest.get(domainId, tid, document.TYPE_HOMEWORK)
+            : null;
         if (!this.user.own(tdoc)) this.checkPerm(PERM.PERM_EDIT_HOMEWORK);
         else this.checkPerm(PERM.PERM_EDIT_HOMEWORK_SELF);
-        const extensionDays = Math.round(
-            (tdoc.endAt.getTime() - tdoc.penaltySince.getTime()) / 36000 / 24,
-        ) / 100;
+        const extensionDays = tid
+            ? Math.round(
+                (tdoc.endAt.getTime() - tdoc.penaltySince.getTime()) / (Time.day / 100),
+            ) / 100
+            : 1;
         const path = [
             ['Hydro', 'homepage'],
             ['homework_main', 'homework_main'],
-            [tdoc.title, 'homework_detail', { tid }, true],
-            ['homework_edit', null],
+            ...tid
+                ? [
+                    [tdoc.title, 'homework_detail', { tid }, true],
+                    ['homework_edit', null],
+                ]
+                : [['homework_create', null]],
         ];
-        const beginAt = moment(tdoc.beginAt).tz(this.user.timeZone);
-        const penaltySince = moment(tdoc.penaltySince).tz(this.user.timeZone);
+        const beginAt = tid
+            ? moment(tdoc.beginAt).tz(this.user.timeZone)
+            : moment().add(1, 'day').tz(this.user.timeZone).hour(0).minute(0).millisecond(0);
+        const penaltySince = tid
+            ? moment(tdoc.penaltySince).tz(this.user.timeZone)
+            : beginAt.clone().add(7, 'days').tz(this.user.timeZone).hour(23).minute(59).millisecond(0);
         this.response.template = 'homework_edit.html';
         this.response.body = {
             tdoc,
@@ -298,10 +256,11 @@ class HomeworkEditHandler extends Handler {
             penaltyRules: yaml.dump(tdoc.penaltyRules),
             pids: tdoc.pids.join(','),
             path,
+            page_name: tid ? 'homework_edit' : 'homework_create',
         };
     }
 
-    @param('tid', Types.ObjectID)
+    @param('tid', Types.ObjectID, true)
     @param('beginAtDate', Types.Date)
     @param('beginAtTime', Types.Time)
     @param('penaltySinceDate', Types.Date)
@@ -315,38 +274,37 @@ class HomeworkEditHandler extends Handler {
     async post(
         domainId: string, tid: ObjectID, beginAtDate: string, beginAtTime: string,
         penaltySinceDate: string, penaltySinceTime: string, extensionDays: number,
-        penaltyRules: string, title: string, content: string, _pids: string, rated = false,
+        penaltyRules: PenaltyRules, title: string, content: string, _pids: string, rated = false,
     ) {
-        const pids = _pids.replace(/，/g, ',').split(',').map((i) => +i).filter((i) => i);
+        const pids = _pids.replace(/，/g, ',').split(',').map((i) => {
+            if ((+i).toString() === i) return +i;
+            return i;
+        }).filter((i) => i);
         const tdoc = await contest.get(domainId, tid, document.TYPE_HOMEWORK);
         if (!this.user.own(tdoc)) this.checkPerm(PERM.PERM_EDIT_HOMEWORK);
         else this.checkPerm(PERM.PERM_EDIT_HOMEWORK_SELF);
-        let beginAt;
-        let penaltySince;
-        try {
-            beginAt = moment.tz(`${beginAtDate} ${beginAtTime}`, this.user.timeZone);
-        } catch (e) {
-            throw new ValidationError('beginAtDate', 'beginAtTime');
-        }
-        try {
-            penaltySince = moment.tz(`${penaltySinceDate} ${penaltySinceTime}`, this.user.timeZone);
-        } catch (e) {
-            throw new ValidationError('endAtDate', 'endAtTime');
-        }
-        let endAt = penaltySince.clone().add(extensionDays, 'days');
+        const beginAt = moment.tz(`${beginAtDate} ${beginAtTime}`, this.user.timeZone);
+        if (!beginAt.isValid()) throw new ValidationError('beginAtDate', 'beginAtTime');
+        const penaltySince = moment.tz(`${penaltySinceDate} ${penaltySinceTime}`, this.user.timeZone);
+        if (!penaltySince.isValid()) throw new ValidationError('endAtDate', 'endAtTime');
+        const endAt = penaltySince.clone().add(extensionDays, 'days');
         if (beginAt.isSameOrAfter(penaltySince)) throw new ValidationError('endAtDate', 'endAtTime');
+        if (penaltySince.isAfter(endAt)) throw new ValidationError('extensionDays');
         await problem.getList(domainId, pids, this.user.hasPerm(PERM.PERM_VIEW_PROBLEM_HIDDEN), true);
-        beginAt = beginAt.toDate();
-        endAt = endAt.toDate();
-        penaltySince = penaltySince.toDate();
-        await contest.edit(domainId, tid, {
-            title, content, beginAt, endAt, pids, penaltySince, penaltyRules, rated,
-        }, document.TYPE_HOMEWORK);
-        if (tdoc.beginAt !== beginAt
-            || tdoc.endAt !== endAt
-            || tdoc.penaltySince !== penaltySince
-            || tdoc.pids.sort().join(' ') !== pids.sort().join(' ')) {
-            await contest.recalcStatus(domainId, tdoc.docId, document.TYPE_HOMEWORK);
+        if (!tid) {
+            tid = await contest.add(domainId, title, content, this.user._id,
+                'homework', beginAt.toDate(), endAt.toDate(), pids, rated,
+                { penaltySince: penaltySince.toDate(), penaltyRules }, document.TYPE_HOMEWORK);
+        } else {
+            await contest.edit(domainId, tid, {
+                title, content, beginAt: beginAt.toDate(), endAt: endAt.toDate(), pids, penaltySince: penaltySince.toDate(), penaltyRules, rated,
+            }, document.TYPE_HOMEWORK);
+            if (tdoc.beginAt !== beginAt.toDate()
+                || tdoc.endAt !== endAt.toDate()
+                || tdoc.penaltySince !== penaltySince.toDate()
+                || tdoc.pids.sort().join(' ') !== pids.sort().join(' ')) {
+                await contest.recalcStatus(domainId, tdoc.docId, document.TYPE_HOMEWORK);
+            }
         }
         this.response.body = { tid };
         this.response.redirect = this.url('homework_detail', { tid });
@@ -405,9 +363,7 @@ class HomeworkCodeHandler extends Handler {
         }
         const zip = new AdmZip();
         const rdocs = await record.getMulti(domainId, {
-            _id: {
-                $in: Array.from(Object.keys(rnames)).map((id) => new ObjectID(id)),
-            },
+            _id: { $in: Array.from(Object.keys(rnames)).map((id) => new ObjectID(id)) },
         }).toArray();
         for (const rdoc of rdocs) {
             zip.addFile(`${rnames[rdoc._id.toHexString()]}.${rdoc.lang}`, Buffer.from(rdoc.code));
@@ -418,7 +374,7 @@ class HomeworkCodeHandler extends Handler {
 
 export async function apply() {
     Route('homework_main', '/homework', HomeworkMainHandler, PERM.PERM_VIEW_HOMEWORK);
-    Route('homework_create', '/homework/create', HomeworkCreateHandler, PERM.PERM_CREATE_HOMEWORK);
+    Route('homework_create', '/homework/create', HomeworkEditHandler, PERM.PERM_CREATE_HOMEWORK);
     Route('homework_detail', '/homework/:tid', HomeworkDetailHandler, PERM.PERM_VIEW_HOMEWORK);
     Route('homework_scoreboard', '/homework/:tid/scoreboard', HomeworkScoreboardHandler, PERM.PERM_VIEW_HOMEWORK_SCOREBOARD);
     Route(
diff --git a/packages/hydrooj/src/handler/judge.ts b/packages/hydrooj/src/handler/judge.ts
index acf128704..a5d12b101 100644
--- a/packages/hydrooj/src/handler/judge.ts
+++ b/packages/hydrooj/src/handler/judge.ts
@@ -23,16 +23,20 @@ const logger = new Logger('judge');
 async function _postJudge(rdoc: RecordDoc) {
     if (typeof rdoc.input === 'string') return;
     const accept = rdoc.status === builtin.STATUS.STATUS_ACCEPTED;
-    const updated = await problem.updateStatus(rdoc.domainId, rdoc.pid, rdoc.uid, rdoc._id, rdoc.status, rdoc.score);
+    const updated = await problem.updateStatus(rdoc.pdomain, rdoc.pid, rdoc.uid, rdoc._id, rdoc.status, rdoc.score);
     if (rdoc.contest) {
         await contest.updateStatus(
             rdoc.domainId, rdoc.contest.tid, rdoc.uid,
             rdoc._id, rdoc.pid, accept, rdoc.score, rdoc.contest.type,
         );
+        await contest.updateStatus(
+            rdoc.domainId, rdoc.contest.tid, rdoc.uid,
+            rdoc._id, `${rdoc.pdomain}:${rdoc.pid}`, accept, rdoc.score, rdoc.contest.type,
+        );
     } else if (accept && updated) await domain.incUserInDomain(rdoc.domainId, rdoc.uid, 'nAccept', 1);
     const pdoc = (accept && updated)
-        ? await problem.inc(rdoc.domainId, rdoc.pid, 'nAccept', 1)
-        : await problem.get(rdoc.domainId, rdoc.pid);
+        ? await problem.inc(rdoc.pdomain, rdoc.pid, 'nAccept', 1)
+        : await problem.get(rdoc.pdomain, rdoc.pid);
     const difficulty = difficultyAlgorithm(pdoc.nSubmit, pdoc.nAccept);
     if (!updated) await record.updateMulti(rdoc.domainId, { uid: rdoc.uid, status: builtin.STATUS.STATUS_ACCEPTED }, { effective: false });
     await Promise.all([
@@ -45,8 +49,8 @@ async function _postJudge(rdoc: RecordDoc) {
 }
 
 export async function next(body: JudgeResultBody) {
-    if (body.rid) body.rid = new ObjectID(body.rid);
-    let rdoc = await record.get(body.domainId, body.rid);
+    body.rid = new ObjectID(body.rid);
+    let rdoc = await record.get(body.rid);
     const $set: Partial<RecordDoc> = {};
     const $push: any = {};
     if (body.case) {
@@ -72,13 +76,13 @@ export async function next(body: JudgeResultBody) {
     if (body.time !== undefined) $set.time = body.time;
     if (body.memory !== undefined) $set.memory = body.memory;
     if (body.progress !== undefined) $set.progress = body.progress;
-    rdoc = await record.update(body.domainId, body.rid, $set, $push);
+    rdoc = await record.update(rdoc.domainId, body.rid, $set, $push);
     bus.boardcast('record/change', rdoc, $set, $push);
 }
 
 export async function end(body: JudgeResultBody) {
     if (body.rid) body.rid = new ObjectID(body.rid);
-    let rdoc = await record.get(body.domainId, body.rid);
+    let rdoc = await record.get(body.rid);
     const $set: Partial<RecordDoc> = {};
     const $push: any = {};
     const $unset: any = { progress: '' };
@@ -97,7 +101,7 @@ export async function end(body: JudgeResultBody) {
     $set.judgeAt = new Date();
     $set.judger = body.judger ?? 1;
     await sleep(100); // Make sure that all 'next' event already triggered
-    rdoc = await record.update(body.domainId, body.rid, $set, $push, $unset);
+    rdoc = await record.update(rdoc.domainId, body.rid, $set, $push, $unset);
     await _postJudge(rdoc);
     bus.boardcast('record/change', rdoc); // trigger a full update
 }
diff --git a/packages/hydrooj/src/handler/problem.ts b/packages/hydrooj/src/handler/problem.ts
index fce9340ba..0e257270a 100644
--- a/packages/hydrooj/src/handler/problem.ts
+++ b/packages/hydrooj/src/handler/problem.ts
@@ -247,7 +247,7 @@ export class ProblemSubmitHandler extends ProblemDetailHandler {
     async get(domainId: string, pid: string | number) {
         this.response.template = 'problem_submit.html';
         const rdocs = await record
-            .getUserInProblemMulti(domainId, this.user._id, this.pdoc.docId)
+            .getUserInProblemMulti(domainId, this.user._id, pid)
             .sort({ _id: -1 })
             .limit(10)
             .toArray();
diff --git a/packages/hydrooj/src/handler/record.ts b/packages/hydrooj/src/handler/record.ts
index e94d8f0ea..8705e2a43 100644
--- a/packages/hydrooj/src/handler/record.ts
+++ b/packages/hydrooj/src/handler/record.ts
@@ -1,4 +1,5 @@
 import { FilterQuery, ObjectID } from 'mongodb';
+import { pick } from 'lodash';
 import {
     ContestNotFoundError, PermissionError, ProblemNotFoundError,
     RecordNotFoundError, UserNotFoundError,
@@ -58,8 +59,10 @@ class RecordListHandler extends Handler {
         const [udict, pdict] = await Promise.all([
             user.getList(domainId, rdocs.map((rdoc) => rdoc.uid)),
             canViewProblem
-                ? problem.getList(domainId, rdocs.map((rdoc) => rdoc.pid), canViewProblemHidden, false)
-                : Object.fromEntries([rdocs.map((rdoc) => [rdoc.pid, problem.create(rdoc.pid, rdoc.pid.toString())])]),
+                ? problem.getList(domainId, rdocs.map(
+                    (rdoc) => (rdoc.domainId === domainId ? rdoc.pid : `${rdoc.pdomain}:${rdoc.pid}`)
+                ), canViewProblemHidden, false)
+                : Object.fromEntries([rdocs.map((rdoc) => [rdoc.pid, { ...problem.default, pid: rdoc.pid }])]),
         ]);
         const path = [
             ['Hydro', 'homepage'],
@@ -100,16 +103,15 @@ class RecordDetailHandler extends Handler {
         }
         // eslint-disable-next-line prefer-const
         let [pdoc, udoc] = await Promise.all([
-            problem.get(domainId, rdoc.pid),
+            problem.get(rdoc.pdomain, rdoc.pid),
             user.getById(domainId, rdoc.uid),
         ]);
-        if (!(pdoc && this.user.hasPerm(PERM.PERM_VIEW_PROBLEM))) {
-            pdoc = problem.create(pdoc?.docId || 0, pdoc?.pid || '*');
-        }
-        if (!rdoc.contest && pdoc.hidden && !this.user.own(pdoc)) {
-            if (!this.user.hasPerm(PERM.PERM_VIEW_PROBLEM_HIDDEN)) {
-                pdoc = problem.create(pdoc.docId, pdoc.pid);
-            }
+        if (
+            !pdoc
+            || !this.user.hasPerm(PERM.PERM_VIEW_PROBLEM)
+            || (!rdoc.contest && pdoc.hidden && !this.user.own(pdoc) && !this.user.hasPerm(PERM.PERM_VIEW_PROBLEM_HIDDEN))
+        ) {
+            pdoc = { ...problem.default, docId: pdoc?.docId || 0, pid: '*' };
         }
         this.response.body = {
             path: [
@@ -162,6 +164,7 @@ class RecordMainConnectionHandler extends ConnectionHandler {
     dispose: bus.Disposable;
     tid: string;
     uid: number;
+    pdomain: string;
     pid: number;
     status: number;
     pretest: boolean;
@@ -172,16 +175,11 @@ class RecordMainConnectionHandler extends ConnectionHandler {
     @param('status', Types.Int, true)
     @param('pretest', Types.Boolean)
     async prepare(domainId: string, tid?: ObjectID, pid?: string, uidOrName?: string, status?: number, pretest = false) {
-        if (tid) {
-            const tdoc = await contest.get(domainId, tid, -1);
-            if (contest.canShowRecord.call(this, tdoc)) this.tid = tid.toHexString();
-            else throw new PermissionError(PERM.PERM_VIEW_CONTEST_HIDDEN_SCOREBOARD);
-        }
         if (tid) {
             const tdoc = await contest.get(domainId, tid, -1);
             if (!tdoc) throw new ContestNotFoundError(domainId, tid);
-            if (!contest.canShowScoreboard.call(this, tdoc, true)) throw new PermissionError(PERM.PERM_VIEW_CONTEST_HIDDEN_SCOREBOARD);
-            this.tid = tid.toHexString();
+            if (contest.canShowScoreboard.call(this, tdoc, true)) this.tid = tid.toHexString();
+            else throw new PermissionError(PERM.PERM_VIEW_CONTEST_HIDDEN_SCOREBOARD);
         }
         if (uidOrName) {
             let udoc = await user.getById(domainId, +uidOrName);
@@ -193,9 +191,13 @@ class RecordMainConnectionHandler extends ConnectionHandler {
             }
         }
         if (pid) {
-            const pdoc = await problem.get(domainId, pid);
-            if (pdoc) this.pid = pdoc.docId;
-            else throw new ProblemNotFoundError(domainId, pid);
+            const pdomain = pid.includes(':') ? pid.split(':')[0] : domainId;
+            const ppid = pid.includes(':') ? +pid.split(':')[1] : pid;
+            const pdoc = await problem.get(pdomain, ppid);
+            if (pdoc) {
+                this.pdomain = pdoc.domainId;
+                this.pid = pdoc.docId;
+            } else throw new ProblemNotFoundError(domainId, pid);
         }
         if (status) this.status = status;
         if (pretest) this.pretest = true;
@@ -219,7 +221,7 @@ class RecordMainConnectionHandler extends ConnectionHandler {
         if (!this.pretest && rdoc.input) return;
         if (rdoc.contest && rdoc.contest.tid.toString() !== this.tid) return;
         if (this.uid && rdoc.uid !== this.uid) return;
-        if (this.pid && rdoc.pid !== this.pid) return;
+        if (this.pid && (rdoc.pid !== this.pid || rdoc.pdomain !== this.pdomain)) return;
         // eslint-disable-next-line prefer-const
         let [udoc, pdoc] = await Promise.all([
             user.getById(this.domainId, rdoc.uid),
diff --git a/packages/hydrooj/src/handler/user.ts b/packages/hydrooj/src/handler/user.ts
index 28d02cb89..7970e056d 100644
--- a/packages/hydrooj/src/handler/user.ts
+++ b/packages/hydrooj/src/handler/user.ts
@@ -206,7 +206,7 @@ class UserDetailHandler extends Handler {
                 this.user.hasPerm(PERM.PERM_VIEW_PROBLEM_HIDDEN), false,
             )
             : Object.fromEntries(rdocs.map(
-                (rdoc) => [rdoc.pid, problem.create(undefined, rdoc.pid.toString())],
+                (rdoc) => [rdoc.pid, { ...problem.default, pid: rdoc.pid }],
             ));
         // Remove sensitive data
         if (!isSelfProfile && sdoc) {
diff --git a/packages/hydrooj/src/interface.ts b/packages/hydrooj/src/interface.ts
index c7ee2d403..2500a859d 100644
--- a/packages/hydrooj/src/interface.ts
+++ b/packages/hydrooj/src/interface.ts
@@ -256,27 +256,31 @@ export interface ContestInfo {
 }
 
 export interface RecordDoc {
-    _id: ObjectID,
-    domainId: string,
-    pid: number
-    uid: number,
-    lang: string,
-    code: string,
-    score: number,
-    memory: number,
-    time: number,
-    judgeTexts: string[],
-    compilerTexts: string[],
-    testCases: TestCase[],
-    rejudged: boolean,
-    judger: number,
-    judgeAt: Date,
-    status: number,
-    hidden: boolean,
-    progress?: number,
-    input?: string,
-    contest?: ContestInfo,
-    effective?: boolean,
+    _id: ObjectID;
+    domainId: string;
+    pdomain: string;
+    pid: number;
+    uid: number;
+    lang: string;
+    code: string;
+    score: number;
+    memory: number;
+    time: number;
+    judgeTexts: string[];
+    compilerTexts: string[];
+    testCases: TestCase[];
+    rejudged: boolean;
+    /** judge uid */
+    judger: number;
+    judgeAt: Date;
+    status: number;
+    progress?: number;
+    /** pretest/script */
+    hidden?: boolean;
+    /** pretest */
+    input?: string;
+    contest?: ContestInfo;
+    effective?: boolean;
 }
 
 export interface ScoreboardNode {
@@ -296,6 +300,9 @@ export interface TrainingNode {
     pids: number[],
 }
 
+export type ExternalProblemId = string; // ${string}:${number}
+export type ProblemId = ExternalProblemId | number;
+
 export interface Tdoc<docType = document['TYPE_CONTEST'] | document['TYPE_HOMEWORK'] | document['TYPE_TRAINING']> extends Document {
     docId: ObjectID,
     docType: docType & number,
@@ -305,7 +312,7 @@ export interface Tdoc<docType = document['TYPE_CONTEST'] | document['TYPE_HOMEWO
     title: string,
     content: string,
     rule: string,
-    pids: number[],
+    pids: ProblemId[],
     rated?: boolean,
 
     // For homework
diff --git a/packages/hydrooj/src/lib/validator.ts b/packages/hydrooj/src/lib/validator.ts
index 0dc1144b9..bc085558b 100644
--- a/packages/hydrooj/src/lib/validator.ts
+++ b/packages/hydrooj/src/lib/validator.ts
@@ -1,6 +1,8 @@
 import { ValidationError } from '../error';
 
 const RE_UID = /^-?\d+$/i;
+const RE_DOMAINID = /^[a-zA-Z][a-zA-Z0-9_]{3,31}$/i;
+const RE_EXTERNAL_PID = /^[a-zA-Z][a-zA-Z0-9_]{3,31}:\d+$/i;
 const RE_PID = /^[a-zA-Z]+[a-zA-Z0-9]*$/i;
 const RE_UNAME = /^.{3,254}$/i;
 const RE_ROLE = /^[_0-9A-Za-z]{1,256}$/i;
@@ -60,6 +62,10 @@ export function validate(scheme: any, arg: any) {
 
 export const isTitle = (s) => s && s.length < 64;
 export const checkTitle = (s) => { if (!(s && s.length < 64)) throw new ValidationError('title'); else return s; };
+export const isDomainId = (s) => RE_DOMAINID.test(s);
+export const checkDomainId = (s) => { if (!isDomainId(s)) throw new ValidationError('domainId'); else return s; };
+export const isExternalPid = (s) => RE_EXTERNAL_PID.test(s);
+export const checkExternalPid = (s) => { if (!isExternalPid(s)) throw new ValidationError('pid'); else return s; };
 export const isUid = (s) => RE_UID.test(s);
 export const checkUid = (s) => { if (!isUid(s)) throw new ValidationError('uid'); else return s; };
 export const isUname = (s) => RE_UNAME.test(s);
@@ -87,6 +93,10 @@ global.Hydro.lib.validator = {
     validate,
     isTitle,
     checkTitle,
+    isDomainId,
+    checkDomainId,
+    isExternalPid,
+    checkExternalPid,
     isUid,
     checkUid,
     isUname,
diff --git a/packages/hydrooj/src/model/contest.ts b/packages/hydrooj/src/model/contest.ts
index 94c8584ef..d78522b3d 100644
--- a/packages/hydrooj/src/model/contest.ts
+++ b/packages/hydrooj/src/model/contest.ts
@@ -8,7 +8,7 @@ import {
     ContestNotAttendedError, ContestScoreboardHiddenError,
 } from '../error';
 import {
-    ContestRule, ContestRules, ProblemDict,
+    ProblemId, ContestRule, ContestRules, ProblemDict,
     ScoreboardNode, ScoreboardRow, Tdoc,
     Udict,
 } from '../interface';
@@ -178,14 +178,20 @@ const oi: ContestRule = {
         const psdict = {};
         // eslint-disable-next-line @typescript-eslint/no-use-before-define
         if (isDone(tdoc)) {
-            const psdocs = await problem.getMultiStatus(tdoc.domainId, {
-                $or: rankedTsdocs.map(([, i]) => ({
-                    uid: i.uid,
-                    docId: { $in: tdoc.pids },
-                })),
-            }).toArray();
-            for (const psdoc of psdocs) {
-                psdict[`${psdoc.uid}/${psdoc.docId}`] = psdoc;
+            const psdocs = await Promise.all(
+                tdoc.pids.map((pid) => {
+                    let pdomain = tdoc.domainId;
+                    if (typeof pid === 'string') {
+                        pdomain = pid.split(':')[0];
+                        pid = +pid.split(':')[1];
+                    }
+                    return problem.getMultiStatus(pdomain, { uid: { $in: uids } }).toArray();
+                }),
+            );
+            for (const tpsdoc of psdocs) {
+                for (const psdoc of tpsdoc) {
+                    psdict[`${psdoc.uid}/${psdoc.docId}`] = psdoc;
+                }
             }
         }
         const rows = [columns];
@@ -397,7 +403,7 @@ function _getStatusJournal(tsdoc) {
 
 export function add(
     domainId: string, title: string, content: string, owner: number,
-    rule: string, beginAt = new Date(), endAt = new Date(), pids = [],
+    rule: string, beginAt = new Date(), endAt = new Date(), pids: ProblemId[] = [],
     rated = false, data: Partial<Tdoc> = {}, type: Type = document.TYPE_CONTEST,
 ) {
     if (!this.RULES[rule]) throw new ValidationError('rule');
@@ -444,12 +450,12 @@ export async function get(domainId: string, tid: ObjectID, type: Type | -1 = doc
     return tdoc;
 }
 
-export async function getRelated(domainId: string, pid: number, type: Type = document.TYPE_CONTEST) {
+export async function getRelated(domainId: string, pid: ProblemId, type: Type = document.TYPE_CONTEST) {
     return await document.getMulti(domainId, type, { pids: pid }).toArray();
 }
 
 export async function updateStatus(
-    domainId: string, tid: ObjectID, uid: number, rid: ObjectID, pid: number,
+    domainId: string, tid: ObjectID, uid: number, rid: ObjectID, pid: ProblemId,
     accept = false, score = 0, type: 30 | 60 = document.TYPE_CONTEST,
 ) {
     const tdoc = await get(domainId, tid, type);
diff --git a/packages/hydrooj/src/model/problem.ts b/packages/hydrooj/src/model/problem.ts
index 53233df99..9ba71a33c 100644
--- a/packages/hydrooj/src/model/problem.ts
+++ b/packages/hydrooj/src/model/problem.ts
@@ -1,12 +1,17 @@
 import { ObjectID, FilterQuery } from 'mongodb';
-import { Dictionary, escapeRegExp, pick } from 'lodash';
+import {
+    Dictionary, escapeRegExp, flatten, groupBy, pick,
+} from 'lodash';
 import { streamToBuffer } from '@hydrooj/utils/lib/utils';
 import type { Readable } from 'stream';
 import * as document from './document';
 import { STATUS } from './builtin';
+import domain from './domain';
 import storage from './storage';
 import { buildProjection } from '../utils';
-import type { ProblemStatusDoc, ProblemDict, Document } from '../interface';
+import type {
+    ProblemStatusDoc, ProblemDict, Document, ProblemId,
+} from '../interface';
 import {
     ArrayKeys, MaybeArray, NumberKeys, Projection,
 } from '../typeutils';
@@ -16,9 +21,6 @@ import { parseConfig } from '../lib/testdataConfig';
 
 export interface ProblemDoc extends Document { }
 export type Field = keyof ProblemDoc;
-const fields: Field[] = [];
-export type Getter = (docId?: number, pid?: string) => Partial<ProblemDoc>;
-const getters: Getter[] = [];
 
 export class ProblemModel {
     static PROJECTION_LIST: Field[] = [
@@ -32,18 +34,47 @@ export class ProblemModel {
         'content', 'html', 'data', 'config', 'additional_file',
     ];
 
-    static extend(getter: Getter) {
-        getters.push(getter);
-        fields.push(...Object.keys(getter(0, '0')) as any);
-    }
+    static default = {
+        _id: new ObjectID(),
+        domainId: 'system',
+        docType: document.TYPE_PROBLEM,
+        docId: 0,
+        pid: null,
+        owner: 1,
+        title: '*',
+        content: '',
+        html: false,
+        nSubmit: 0,
+        nAccept: 0,
+        tag: [],
+        data: [],
+        additional_file: [],
+        stats: {},
+        hidden: true,
+        config: '',
+        difficulty: 0,
+    };
 
-    static create(docId?: number, pid?: string) {
-        const result = {} as ProblemDoc;
-        for (const getter of getters) {
-            Object.assign(result, getter(docId, pid));
-        }
-        return result;
-    }
+    static deleted = {
+        _id: new ObjectID(),
+        domainId: 'system',
+        docType: document.TYPE_PROBLEM,
+        docId: -1,
+        pid: null,
+        owner: 1,
+        title: '*',
+        content: 'Deleted Problem',
+        html: false,
+        nSubmit: 0,
+        nAccept: 0,
+        tag: [],
+        data: [],
+        additional_file: [],
+        stats: {},
+        hidden: true,
+        config: '',
+        difficulty: 0,
+    };
 
     static async add(
         domainId: string, pid: string = null, title: string, content: string, owner: number,
@@ -80,6 +111,12 @@ export class ProblemModel {
         if (typeof pid !== 'number') {
             if (Number.isSafeInteger(parseInt(pid, 10))) pid = parseInt(pid, 10);
         }
+        if (typeof pid === 'string') {
+            if (pid.includes(':')) {
+                domainId = pid.split(':')[0];
+                pid = +pid.split(':')[1];
+            }
+        }
         const res = typeof pid === 'number'
             ? await document.get(domainId, document.TYPE_PROBLEM, pid, projection)
             : (await document.getMulti(domainId, document.TYPE_PROBLEM, { pid }).toArray())[0];
@@ -121,7 +158,12 @@ export class ProblemModel {
         return document.deleteSub(domainId, document.TYPE_PROBLEM, pid, key, values);
     }
 
-    static inc(domainId: string, _id: number, field: NumberKeys<ProblemDoc> | string, n: number): Promise<ProblemDoc> {
+    static inc(domainId: string, _id: ProblemId, field: NumberKeys<ProblemDoc> | string, n: number): Promise<ProblemDoc> {
+        if (typeof _id === 'string') {
+            if (!_id.includes(':')) throw new Error(`model.problem.inc: invalid _id <${_id}>`);
+            domainId = _id.split(':')[0];
+            _id = +_id.split(':')[1];
+        }
         return document.inc(domainId, document.TYPE_PROBLEM, _id, field as any, n);
     }
 
@@ -191,16 +233,43 @@ export class ProblemModel {
     }
 
     static async getList(
-        domainId: string, pids: Array<number | string>,
+        domainId: string, pids: ProblemId[],
         getHidden = false, doThrow = true, projection = ProblemModel.PROJECTION_PUBLIC,
     ): Promise<ProblemDict> {
-        pids = Array.from(new Set(pids)).map((i) => (+i ? +i : i));
+        const parsed = groupBy(
+            Array.from(new Set(pids)).map((i) => ({
+                domainId: (typeof i === 'string' && i.includes(':')) ? i.split(':')[0] : domainId,
+                pid: (typeof i === 'string' && i.includes(':')) ? +i.split(':')[1] : i,
+            })),
+            'domainId',
+        );
         const r = {};
         const l = {};
-        const q: any = { $or: [{ docId: { $in: pids } }, { pid: { $in: pids } }] };
-        if (!getHidden) q.hidden = false;
-        const pdocs = await document.getMulti(domainId, document.TYPE_PROBLEM, q)
-            .project(buildProjection(projection)).toArray();
+        const ddocs = await Promise.all(Object.keys(parsed).map((i) => domain.get(i)));
+        const f = ddocs.filter((i) => !(
+            i.share === '*'
+            || (`,${i.share.replace(/，/g, ',').split(',').map((i) => i.trim()).join(',')},`).includes(`,${domainId},`)
+        ));
+        if (f.length) {
+            if (doThrow) throw new ProblemNotFoundError(f[0]._id, parsed[f[0]._id][0].pid);
+            else {
+                for (const sf of f) {
+                    for (const pinfo of parsed[sf._id]) {
+                        r[pinfo.pid] = { ...ProblemModel.default, domainId: sf._id, pid: pinfo.pid };
+                    }
+                    delete parsed[sf._id];
+                }
+            }
+        }
+        const tasks = [];
+        for (const task in parsed) {
+            const range = { $in: parsed[task].map((i) => i.pid) };
+            const q: any = { $or: [{ docId: range }, { pid: range }] };
+            if (!getHidden) q.hidden = false;
+            console.log(task, parsed[task]);
+            tasks.push(document.getMulti(task, document.TYPE_PROBLEM, q).project(buildProjection(projection)).toArray());
+        }
+        const pdocs = flatten(await Promise.all(tasks));
         for (const pdoc of pdocs) {
             try {
                 // eslint-disable-next-line no-await-in-loop
@@ -208,15 +277,20 @@ export class ProblemModel {
             } catch (e) {
                 pdoc.config = `Cannot parse: ${e.message}`;
             }
-            r[pdoc.docId] = pdoc;
-            l[pdoc.pid] = pdoc;
+            if (pdoc.domainId === domainId) {
+                r[pdoc.docId] = pdoc;
+                if (pdoc.pid) l[pdoc.pid] = pdoc;
+            } else {
+                r[`${pdoc.domainId}:${pdoc.docId}`] = pdoc;
+                if (pdoc.pid) l[`${pdoc.domainId}:${pdoc.pid}`] = pdoc;
+            }
         }
         // TODO enhance
         if (pdocs.length !== pids.length) {
             for (const pid of pids) {
                 if (!(r[pid] || l[pid])) {
                     if (doThrow) throw new ProblemNotFoundError(domainId, pid);
-                    else r[pid] = ProblemModel.create(undefined, pid.toString());
+                    else r[pid] = { ...ProblemModel.default, domainId, pid };
                 }
             }
         }
@@ -273,26 +347,5 @@ bus.on('problem/delTestdata', async (domainId, docId, names) => {
     await ProblemModel.edit(domainId, docId, { config: '' });
 });
 
-ProblemModel.extend((docId, pid) => ({
-    _id: new ObjectID(),
-    domainId: 'system',
-    docType: document.TYPE_PROBLEM,
-    docId: docId || -1,
-    pid: pid || docId.toString(),
-    owner: 1,
-    title: '*',
-    content: '',
-    html: false,
-    nSubmit: 0,
-    nAccept: 0,
-    tag: [],
-    data: [],
-    additional_file: [],
-    stats: {},
-    hidden: true,
-    config: '',
-    difficulty: 0,
-}));
-
 global.Hydro.model.problem = ProblemModel;
 export default ProblemModel;
diff --git a/packages/hydrooj/src/model/record.ts b/packages/hydrooj/src/model/record.ts
index 6a7a7023c..22f8517f7 100644
--- a/packages/hydrooj/src/model/record.ts
+++ b/packages/hydrooj/src/model/record.ts
@@ -8,7 +8,9 @@ import moment from 'moment';
 import { STATUS } from './builtin';
 import task from './task';
 import problem from './problem';
-import { RecordDoc, ContestInfo, ProblemConfigFile } from '../interface';
+import {
+    RecordDoc, ContestInfo, ProblemConfigFile, ExternalProblemId,
+} from '../interface';
 import { ArgMethod, buildProjection, Time } from '../utils';
 import { MaybeArray } from '../typeutils';
 import * as bus from '../service/bus';
@@ -29,9 +31,13 @@ class RecordModel {
         return base - ((pending + 0.5) * (sum(timeRecent.map((i) => i.time || 0)) / 10000));
     }
 
-    static async get(domainId: string, _id: ObjectID): Promise<RecordDoc | null> {
+    static async get(_id: ObjectID): Promise<RecordDoc | null>
+    static async get(domainId: string, _id: ObjectID): Promise<RecordDoc | null>
+    static async get(arg0, arg1?) {
+        const _id = arg1 || arg0;
+        const domainId = arg1 ? arg0 : null;
         const res = await RecordModel.coll.findOne({ _id });
-        if (res && res.domainId === domainId) return res;
+        if (res.domainId === (domainId || res.domainId)) return res;
         return null;
     }
 
@@ -55,7 +61,7 @@ class RecordModel {
         const rdoc = await RecordModel.get(domainId, rid);
         let data = [];
         if (rdoc.pid) {
-            const pdoc = await problem.get(domainId, rdoc.pid);
+            const pdoc = await problem.get(rdoc.pdomain, rdoc.pid);
             data = pdoc.data;
         }
         delete rdoc._id;
@@ -71,15 +77,21 @@ class RecordModel {
     }
 
     static async add(
-        domainId: string, pid: number, uid: number,
+        domainId: string, pid: ExternalProblemId | number, uid: number,
         lang: string, code: string, addTask: boolean, contestOrConfig?: ContestInfo | string,
     ) {
+        let pdomain = domainId;
+        if (typeof pid === 'string') {
+            pdomain = pid.split(':')[0];
+            pid = +pid.split(':')[1];
+        }
         const data: RecordDoc = {
             status: STATUS.STATUS_WAITING,
             _id: new ObjectID(),
             uid,
             code,
             lang,
+            pdomain,
             pid,
             domainId,
             score: 0,
@@ -189,16 +201,20 @@ class RecordModel {
     }
 
     @ArgMethod
-    static getUserInProblemMulti(
-        domainId: string, uid: number, pid: number,
-        getHidden: boolean = false,
-    ) {
-        if (!getHidden) {
+    static getUserInProblemMulti(domainId: string, uid: number, pid: ExternalProblemId | number, contestInfo?: ContestInfo) {
+        let pdomain = domainId;
+        if (typeof pid === 'string') {
+            pdomain = pid.split(':')[0];
+            pid = +pid.split(':')[1];
+        }
+        if (!contestInfo) {
             return RecordModel.coll.find({
-                domainId, uid, pid, hidden: false,
+                domainId, uid, pdomain, pid, contest: { $exists: false },
             });
         }
-        return RecordModel.coll.find({ domainId, uid, pid });
+        return RecordModel.coll.find({
+            domainId, uid, pdomain, pid, contest: contestInfo,
+        });
     }
 
     @ArgMethod
@@ -207,8 +223,12 @@ class RecordModel {
     }
 }
 
-bus.on('problem/delete', (domainId, docId) => RecordModel.coll.deleteMany({ domainId, pid: docId }));
-bus.on('domain/delete', (domainId) => RecordModel.coll.deleteMany({ domainId }));
+// Mark problem as deleted
+bus.on('problem/delete', (domainId, docId) => RecordModel.coll.updateMany({ pdomain: domainId, pid: docId }, { $set: { pid: -1 } }));
+bus.on('domain/delete', (domainId) => Promise.all([
+    RecordModel.coll.deleteMany({ domainId }),
+    RecordModel.coll.updateMany({ pdomain: domainId }, { $set: { docId: -1 } }),
+]));
 
 export default RecordModel;
 global.Hydro.model.record = RecordModel;
diff --git a/packages/hydrooj/src/model/setting.ts b/packages/hydrooj/src/model/setting.ts
index e09bc1031..0f757a152 100644
--- a/packages/hydrooj/src/model/setting.ts
+++ b/packages/hydrooj/src/model/setting.ts
@@ -138,6 +138,7 @@ AccountSetting(
 DomainSetting(
     Setting('setting_domain', 'name', 'New domain', 'text', 'name'),
     Setting('setting_domain', 'avatar', '', 'text', 'avatar', 'Will be used as the domain icon.'),
+    Setting('setting_domain', 'share', '', 'text', 'Share problem with domain (* for any)'),
     Setting('setting_domain', 'bulletin', '', 'markdown', 'Bulletin'),
     Setting('setting_storage', 'host', '', 'text', 'Custom host', null, FLAG_HIDDEN | FLAG_DISABLED),
 );
diff --git a/packages/hydrooj/src/pipelineUtils.ts b/packages/hydrooj/src/pipelineUtils.ts
index d14ea05b9..5163f6423 100644
--- a/packages/hydrooj/src/pipelineUtils.ts
+++ b/packages/hydrooj/src/pipelineUtils.ts
@@ -1,10 +1,13 @@
 /* eslint-disable no-await-in-loop */
 import { FilterQuery } from 'mongodb';
-import type { DomainDoc, Udoc, ProblemStatusDoc } from './interface';
+import type {
+    DomainDoc, Udoc, ProblemStatusDoc, RecordDoc,
+} from './interface';
 import domain from './model/domain';
 import * as document from './model/document';
 import user from './model/user';
 import problem, { Field, ProblemDoc } from './model/problem';
+import RecordModel from './model/record';
 
 export async function iterateAllDomain(cb: (ddoc: DomainDoc, current?: number, total?: number) => Promise<any>) {
     const ddocs = await domain.getMulti().toArray();
@@ -56,3 +59,16 @@ export async function iterateAllProblem(
         await iterateAllProblemInDomain(d._id, fields, cb);
     });
 }
+
+export async function iterateAllRecord(
+    cb: (rdoc: RecordDoc, current: number, total: number) => any,
+) {
+    const total = await RecordModel.coll.count();
+    let i = 0;
+    const cursor = RecordModel.coll.find().sort('_id', 1);
+    while (await cursor.hasNext()) {
+        const rdoc = await cursor.next();
+        i++;
+        await cb(rdoc, i, total);
+    }
+}
diff --git a/packages/hydrooj/src/service/server.ts b/packages/hydrooj/src/service/server.ts
index e155306e5..15032bbd0 100644
--- a/packages/hydrooj/src/service/server.ts
+++ b/packages/hydrooj/src/service/server.ts
@@ -349,11 +349,11 @@ export class HandlerCommon {
         const query: any = {};
         for (const key in kwargs) {
             if (kwargs[key] instanceof ObjectID) args[key] = kwargs[key].toHexString();
-            else args[key] = encodeURIComponent(kwargs[key].toString());
+            else args[key] = kwargs[key].toString().replace(/\//g, '%2F');
         }
         for (const key in kwargs.query || {}) {
             if (query[key] instanceof ObjectID) query[key] = kwargs.query[key].toHexString();
-            else query[key] = encodeURIComponent(kwargs.query[key].toString());
+            else query[key] = kwargs.query[key].toString().replace(/\//g, '%2F');
         }
         try {
             const { anchor } = args;
diff --git a/packages/hydrooj/src/service/storage.ts b/packages/hydrooj/src/service/storage.ts
index 36d19f20a..57bb61b94 100644
--- a/packages/hydrooj/src/service/storage.ts
+++ b/packages/hydrooj/src/service/storage.ts
@@ -107,6 +107,7 @@ class StorageService {
             this.error = null;
         } catch (e) {
             logger.warn('Storage init fail. will retry later.');
+            if (process.env.DEV) logger.warn(e);
             this.error = e.toString();
             setTimeout(async () => {
                 await this.start();
diff --git a/packages/hydrooj/src/upgrade.ts b/packages/hydrooj/src/upgrade.ts
index 89b83c9f4..1b75811eb 100644
--- a/packages/hydrooj/src/upgrade.ts
+++ b/packages/hydrooj/src/upgrade.ts
@@ -393,6 +393,11 @@ const scripts: UpgradeScript[] = [
         });
         return true;
     },
+    async function _29_30() {
+        const _FRESH_INSTALL_IGNORE = 1;
+        await iterateAllDomain((ddoc) => RecordModel.coll.updateMany({ domainId: ddoc._id }, { $set: { pdomain: ddoc._id } }));
+        return true;
+    },
 ];
 
 export default scripts;
diff --git a/packages/migrate-vijos/package.json b/packages/migrate-vijos/package.json
index 7f6acec40..07474fb60 100644
--- a/packages/migrate-vijos/package.json
+++ b/packages/migrate-vijos/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@hydrooj/migrate-vijos",
-    "version": "1.4.2",
+    "version": "1.4.3",
     "main": "package.json",
     "repository": "git@github.com:hydro-dev/Hydro.git",
     "author": "undefined <i@undefined.moe>",
diff --git a/packages/migrate-vijos/script.ts b/packages/migrate-vijos/script.ts
index 0b635628c..e167a6c9e 100644
--- a/packages/migrate-vijos/script.ts
+++ b/packages/migrate-vijos/script.ts
@@ -220,6 +220,7 @@ const tasks = {
             code: doc.code,
             lang: doc.lang,
             uid: doc.uid,
+            pdomain: doc.domain_id,
             pid: pid(doc.pid),
             domainId: doc.domain_id,
             judger: doc.judge_uid || 1,
diff --git a/packages/ui-default/package.json b/packages/ui-default/package.json
index 14b4ffd9d..b0d500dab 100644
--- a/packages/ui-default/package.json
+++ b/packages/ui-default/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@hydrooj/ui-default",
-  "version": "4.10.8",
+  "version": "4.11.0",
   "author": "undefined <i@undefined.moe>",
   "license": "AGPL-3.0",
   "main": "hydro.js",
diff --git a/packages/ui-default/templates/problem_detail.html b/packages/ui-default/templates/problem_detail.html
index 3bafcfb65..2829451cb 100644
--- a/packages/ui-default/templates/problem_detail.html
+++ b/packages/ui-default/templates/problem_detail.html
@@ -15,13 +15,13 @@
   {{ set(UiContext, 'postSubmitUrl', url('contest_detail_problem_submit' if tdoc.docType == model.document.TYPE_CONTEST else 'homework_detail_problem_submit', pid=pdoc.docId, tid=tdoc.docId)) }}
   {{ set(UiContext, 'getSubmissionsUrl', url('contest_detail_problem_submit' if tdoc.docType == model.document.TYPE_CONTEST else 'homework_detail_problem_submit', pid=pdoc.docId, tid=tdoc.docId)) }}
   {{ set(UiContext, 'getRecordDetailUrl', url('record_detail', rid='{rid}', query={tid:tdoc.docId})) }}
-  {{ set(UiContext, 'pretestConnUrl', "/record-conn?pretest=1&uid=" + handler.user._id + "&pid=" + pdoc.pid|default(pdoc.docId) + "&domainId=" + handler.domainId + "&tid=" + tdoc.docId) }}
+  {{ set(UiContext, 'pretestConnUrl', "/record-conn?pretest=1&uid=" + handler.user._id + "&pid=" + pdoc.docId + "&domainId=" + handler.domainId + "&tid=" + tdoc.docId) }}
 {% else %}
   {{ set(UiContext, 'canViewRecord', true) }}
   {{ set(UiContext, 'postSubmitUrl', url('problem_submit', pid=pdoc.docId)) }}
   {{ set(UiContext, 'getSubmissionsUrl', url('problem_submit', pid=pdoc.docId)) }}
   {{ set(UiContext, 'getRecordDetailUrl', url('record_detail', rid='{rid}')) }}
-  {{ set(UiContext, 'pretestConnUrl', "/record-conn?pretest=1&uid=" + handler.user._id + "&pid=" + pdoc.pid|default(pdoc.docId) + "&domainId=" + handler.domainId) }}
+  {{ set(UiContext, 'pretestConnUrl', "/record-conn?pretest=1&uid=" + handler.user._id + "&pid=" + pdoc.docId + "&domainId=" + handler.domainId) }}
 {% endif %}
 </script>
 <div class="row">
diff --git a/packages/utils/lib/utils.ts b/packages/utils/lib/utils.ts
index 3de316e93..95d2a3895 100644
--- a/packages/utils/lib/utils.ts
+++ b/packages/utils/lib/utils.ts
@@ -1,7 +1,7 @@
 import path from 'path';
 import fs from 'fs-extra';
 import os from 'os';
-import { Duplex } from 'stream';
+import { Duplex, Readable } from 'stream';
 import { ObjectID } from 'mongodb';
 import { isMoment } from 'moment';
 import type { Moment } from 'moment-timezone';
@@ -192,11 +192,20 @@ export function isClass(obj: any, strict = false) {
     return false;
 }
 
-export function streamToBuffer(stream): Promise<Buffer> {
+export function streamToBuffer(stream: any, maxSize = 0): Promise<Buffer> {
     return new Promise((resolve, reject) => {
         const buffers = [];
+        let length = 0;
+        function onData(data) {
+            buffers.push(data);
+            length += data.length;
+            if (maxSize && length > maxSize) {
+                stream.removeListener('data', onData);
+                reject(new Error('buffer length exceeded'));
+            }
+        }
         stream.on('error', reject);
-        stream.on('data', (data) => buffers.push(data));
+        stream.on('data', onData);
         stream.on('end', () => resolve(Buffer.concat(buffers)));
     });
 }