diff --git a/.env.example b/.env.example
index e020b3b8..d37e0183 100644
--- a/.env.example
+++ b/.env.example
@@ -62,4 +62,4 @@ GOOGLE_DRIVE_REFRESH_TOKEN=
 GOOGLE_DRIVE_FOLDER_ID=
 
 GEOIP2_DATABASE=
-EXAM_PROGRESS_UPDATE_PROBABILITY=60
+EXAM_PROGRESS_UPDATE_PROBABILITY=20
diff --git a/admin/src/utils/api.js b/admin/src/utils/api.js
index d38417a5..647ec5d8 100644
--- a/admin/src/utils/api.js
+++ b/admin/src/utils/api.js
@@ -84,6 +84,9 @@ const api = {
     avoidExamUser: (id) => {
         return axios.put('exam-users-avoid', {id});
     },
+    recoverExamUser: (id) => {
+        return axios.put('exam-users-recover', {id});
+    },
     storeExamUser: (params) => {
         return axios.post('exam-users', params);
     },
diff --git a/admin/src/views/user/detail.vue b/admin/src/views/user/detail.vue
index fb53be77..972777b2 100644
--- a/admin/src/views/user/detail.vue
+++ b/admin/src/views/user/detail.vue
@@ -125,6 +125,15 @@
                                         <el-button type="info" size="small">Avoid</el-button>
                                     </template>
                                 </el-popconfirm>
+                                <el-popconfirm
+                                    v-if="examInfo.status === -1"
+                                    title="Confirm Recover ?"
+                                    @confirm="handleRecoverExam(examInfo.id)"
+                                >
+                                    <template #reference>
+                                        <el-button type="primary" size="small">Recover</el-button>
+                                    </template>
+                                </el-popconfirm>
                             </td>
                         </tr>
                     </table>
@@ -205,6 +214,12 @@ export default {
             await fetchPageData()
         }
 
+        const handleRecoverExam = async (id) => {
+            let res = await api.recoverExamUser(id)
+            ElMessage.success(res.msg)
+            await fetchPageData()
+        }
+
         const handleAssignExam = async () => {
             assignExam.value.open(id)
         }
@@ -230,6 +245,7 @@ export default {
             handleRemoveExam,
             handleAvoidExam,
             handleAssignExam,
+            handleRecoverExam,
             handleEnableUser,
             handleViewInviteInfo,
             handleDisableUser,
diff --git a/app/Http/Controllers/ExamUserController.php b/app/Http/Controllers/ExamUserController.php
index 6b7db3ae..17db4588 100644
--- a/app/Http/Controllers/ExamUserController.php
+++ b/app/Http/Controllers/ExamUserController.php
@@ -99,4 +99,11 @@ class ExamUserController extends Controller
         return $this->success($result, 'Avoid user exam success!');
     }
 
+    public function recover(Request $request)
+    {
+        $request->validate(['id' => 'required']);
+        $result = $this->repository->recoverExamUser($request->id);
+        return $this->success($result, 'Recover user exam success!');
+    }
+
 }
diff --git a/app/Models/ExamIndexInitValue.php b/app/Models/ExamIndexInitValue.php
new file mode 100644
index 00000000..64dcd653
--- /dev/null
+++ b/app/Models/ExamIndexInitValue.php
@@ -0,0 +1,10 @@
+<?php
+
+namespace App\Models;
+
+class ExamIndexInitValue extends NexusModel
+{
+    protected $fillable = ['uid', 'exam_id', 'index', 'value',];
+
+    public $timestamps = true;
+}
diff --git a/app/Repositories/ExamRepository.php b/app/Repositories/ExamRepository.php
index 7ec1c805..f33fea93 100644
--- a/app/Repositories/ExamRepository.php
+++ b/app/Repositories/ExamRepository.php
@@ -3,6 +3,7 @@ namespace App\Repositories;
 
 use App\Exceptions\NexusException;
 use App\Models\Exam;
+use App\Models\ExamIndexInitValue;
 use App\Models\ExamProgress;
 use App\Models\ExamUser;
 use App\Models\Message;
@@ -91,12 +92,22 @@ class ExamRepository extends BaseRepository
         return $exam;
     }
 
+    /**
+     * delete an exam task, also will delete all exam user and progress.
+     *
+     * @param $id
+     * @return bool
+     */
     public function delete($id)
     {
         $exam = Exam::query()->findOrFail($id);
         DB::transaction(function () use ($exam) {
-            ExamUser::query()->where('exam_id', $exam->id)->delete();
-            ExamProgress::query()->where('exam_id', $exam->id)->delete();
+            do {
+                $deleted = ExamUser::query()->where('exam_id', $exam->id)->limit(10000)->delete();
+            } while ($deleted > 0);
+            do {
+                $deleted = ExamProgress::query()->where('exam_id', $exam->id)->limit(10000)->delete();
+            } while ($deleted > 0);
             $exam->delete();
         });
         return true;
@@ -232,8 +243,9 @@ class ExamRepository extends BaseRepository
             $data['end'] = $end;
         }
         do_log("$logPrefix, data: " . nexus_json_encode($data));
-        $result = $user->exams()->create($data);
-        return $result;
+        $examUser = $user->exams()->create($data);
+        $this->initProgress($examUser, $user);
+        return $examUser;
     }
 
     public function listUser(array $params)
@@ -343,6 +355,41 @@ class ExamRepository extends BaseRepository
         return true;
     }
 
+    public function initProgress($examUser, $user = null)
+    {
+        if (!$examUser instanceof ExamUser) {
+            $examUser = ExamUser::query()->findOrFail((int)$examUser);
+        }
+        $exam = $examUser->exam;
+        if (!$user instanceof User) {
+            $user = $examUser->user()->select(['id', 'uploaded', 'downloaded', 'seedtime', 'leechtime', 'seedbonus'])->first();
+        }
+        $insert = [
+            'uid' => $user->id,
+            'exam_id' => $exam->id,
+        ];
+        foreach ($exam->indexes as $key => $index) {
+            if (!isset($index['checked']) || !$index['checked']) {
+                continue;
+            }
+            $insert['index'] = $index['index'];
+            if ($index['index'] == Exam::INDEX_UPLOADED) {
+                $insert['value'] = $user->uploaded;
+            } elseif ($index['index'] == Exam::INDEX_DOWNLOADED) {
+                $insert['value'] = $user->downloaded;
+            } elseif ($index['index'] == Exam::INDEX_SEED_BONUS) {
+                $insert['value'] = $user->seedbonus;
+            } elseif ($index['index'] == Exam::INDEX_SEED_TIME_AVERAGE) {
+                $insert['value'] = 0;
+            } else {
+                throw new \RuntimeException("Unknown index: {$index['index']}");
+            }
+            ExamIndexInitValue::query()->insert($insert);
+            do_log("insert: " . json_encode($insert));
+        }
+        return true;
+    }
+
     public function getUserExamProgress($uid, $status = null, $with = ['exam', 'user'])
     {
         $logPrefix = "uid: $uid";
@@ -449,7 +496,9 @@ class ExamRepository extends BaseRepository
     {
         $examUser = ExamUser::query()->findOrFail($examUserId);
         $result = DB::transaction(function () use ($examUser) {
-            $examUser->progresses()->delete();
+            do {
+                $deleted = $examUser->progresses()->limit(10000)->delete();
+            } while ($deleted > 0);
             return $examUser->delete();
         });
         return $result;
@@ -457,11 +506,18 @@ class ExamRepository extends BaseRepository
 
     public function avoidExamUser(int $examUserId)
     {
-        $examUser = ExamUser::query()->findOrFail($examUserId);
+        $examUser = ExamUser::query()->where('status',ExamUser::STATUS_NORMAL)->findOrFail($examUserId);
         $result = $examUser->update(['status' => ExamUser::STATUS_AVOIDED]);
         return $result;
     }
 
+    public function recoverExamUser(int $examUserId)
+    {
+        $examUser = ExamUser::query()->where('status',ExamUser::STATUS_AVOIDED)->findOrFail($examUserId);
+        $result = $examUser->update(['status' => ExamUser::STATUS_NORMAL]);
+        return $result;
+    }
+
     public function cronjonAssign()
     {
         $exams = $this->listValid(null, Exam::DISCOVERED_YES);
@@ -523,17 +579,16 @@ class ExamRepository extends BaseRepository
 //                    do_log("$currentLogPrefix, exam not match this user.");
 //                    continue;
 //                }
-                $insert[] = [
+                $insert = [
                     'uid' => $user->id,
                     'exam_id' => $exam->id,
                     'created_at' => $now,
                     'updated_at' => $now,
                 ];
                 do_log("$currentLogPrefix, exam will be assigned to this user.");
-            }
-            if (!empty($insert)) {
-                $result += count($insert);
-                ExamUser::query()->insert($insert);
+                $examUser = ExamUser::query()->create($insert);
+                $this->initProgress($examUser, $user);
+                $result++;
             }
         }
         return $result;
diff --git a/database/migrations/2021_06_11_014259_create_exam_index_init_values_table.php b/database/migrations/2021_06_11_014259_create_exam_index_init_values_table.php
new file mode 100644
index 00000000..51733d2b
--- /dev/null
+++ b/database/migrations/2021_06_11_014259_create_exam_index_init_values_table.php
@@ -0,0 +1,37 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+class CreateExamIndexInitValuesTable extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::create('exam_index_init_values', function (Blueprint $table) {
+            $table->id();
+            $table->integer('uid')->index();
+            $table->integer('exam_user_id');
+            $table->integer('exam_id')->index();
+            $table->integer('index')->index();
+            $table->bigInteger('value');
+            $table->timestamps();
+            $table->unique(['exam_user_id', 'exam_id', 'index']);
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::dropIfExists('exam_index_init_values');
+    }
+}
diff --git a/routes/api.php b/routes/api.php
index bec01c9d..013c0a56 100644
--- a/routes/api.php
+++ b/routes/api.php
@@ -50,6 +50,7 @@ Route::group(['middleware' => ['auth:sanctum', 'permission', 'locale']], functio
 
     Route::resource('exam-users', \App\Http\Controllers\ExamUserController::class);
     Route::put('exam-users-avoid', [\App\Http\Controllers\ExamUserController::class, 'avoid']);
+    Route::put('exam-users-recover', [\App\Http\Controllers\ExamUserController::class, 'recover']);
 
     Route::get('dashboard/system-info', [\App\Http\Controllers\DashboardController::class, 'systemInfo']);
     Route::get('dashboard/stat-data', [\App\Http\Controllers\DashboardController::class, 'statData']);