diff --git a/db/app_uoj233.sql b/db/app_uoj233.sql
index 0f2dfcc..fe140ac 100644
--- a/db/app_uoj233.sql
+++ b/db/app_uoj233.sql
@@ -185,7 +185,7 @@ CREATE TABLE `contests` (
   `zan` int NOT NULL DEFAULT '0',
   PRIMARY KEY (`id`),
   KEY `status` (`status`,`id`) USING BTREE
-) ENGINE=MyISAM DEFAULT CHARSET=utf8mb4;
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
 /*!40101 SET character_set_client = @saved_cs_client */;
 
 --
@@ -337,7 +337,7 @@ CREATE TABLE `contests_submissions` (
   `cnt` int DEFAULT NULL,
   `n_failures` int DEFAULT NULL,
   PRIMARY KEY (`contest_id`,`submitter`,`problem_id`)
-) ENGINE=MyISAM DEFAULT CHARSET=utf8mb4;
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
 /*!40101 SET character_set_client = @saved_cs_client */;
 
 --
diff --git a/web/app/models/DB.php b/web/app/models/DB.php
index 3edc229..4979dd1 100644
--- a/web/app/models/DB.php
+++ b/web/app/models/DB.php
@@ -4,14 +4,14 @@ class DB {
 	public static mysqli $conn;
 	public static array $cache = [];
 	public static bool $in_transaction = false;
-	
+
 	const WLOCK = "WRITE";
 	const RLOCK = "READ";
 
 	const ASSOC = MYSQLI_ASSOC;
 	const NUM = MYSQLI_NUM;
 	const BOTH = MYSQLI_BOTH;
-	
+
 	public static function init() {
 		$server = UOJConfig::$data['database']['host'];
 		$username = UOJConfig::$data['database']['username'];
@@ -19,7 +19,7 @@ class DB {
 		$dbname = UOJConfig::$data['database']['database'];
 		DB::$conn = new mysqli($server, $username, $password, $dbname);
 		if (DB::$conn->connect_error) {
-			UOJLog::error('database initialization failed: '. DB::$conn->connect_error);
+			UOJLog::error('database initialization failed: ' . DB::$conn->connect_error);
 			die('There is something wrong with the database >_<... Connection failed');
 		}
 		if (!DB::$conn->set_charset("utf8mb4")) {
@@ -27,113 +27,113 @@ class DB {
 			die('There is something wrong with the database >_<.... Charset utf8 not supported');
 		}
 	}
-	
+
 	// lc: local cache
 	public static function lc() {
 		return new DBUseLocalCache('');
 	}
-	
+
 	public static function escape($str) {
 		return DB::$conn->real_escape_string($str);
 	}
-    public static function raw($str) {
-    	return new DBRawString($str);
-    }
-    public static function rawbracket($q) {
-    	return DB::raw(DB::bracket($q));
-    }
-    public static function rawvalue($str) {
-    	return DB::raw(DB::value($str));
-    }
-    public static function rawtuple(array $vals) {
-    	return DB::raw(DB::tuple($vals));
-    }
-    public static function call($fun, ...$args) {
-    	return DB::raw("{$fun}(".implode(',', array_map('DB::value', $args)).')');
-    }
-    public static function now() {
-    	return DB::call('now');
-    }
-    public static function instr($str, $substr) {
-    	return DB::call('instr', $str, $substr);
-    }
-    public static function cast_as_json($value) {
-    	return DB::raw('cast('.DB::value($value).' as json)');
-    } 
-    public static function json_set($json_doc, ...$args) {
-    	return DB::call('json_set', DB::raw($json_doc), ...$args);
-    }
-    public static function json_insert($json_doc, ...$args) {
-    	return DB::call('json_insert', DB::raw($json_doc), ...$args);
-    }
-    public static function json_replace($json_doc, ...$args) {
-    	return DB::call('json_replace', DB::raw($json_doc), ...$args);
-    }
-    public static function json_remove($json_doc, ...$args) {
-    	return DB::call('json_remove', DB::raw($json_doc), ...$args);
-    }
-    public static function json_array_append($json_doc, ...$args) {
-    	return DB::call('json_array_append', DB::raw($json_doc), ...$args);
-    }
-    public static function json_array_insert($json_doc, ...$args) {
-    	return DB::call('json_array_insert', DB::raw($json_doc), ...$args);
-    }
-    public static function json_unquote($json_doc) {
-    	return DB::call('json_unquote', DB::raw($json_doc));
-    }
+	public static function raw($str) {
+		return new DBRawString($str);
+	}
+	public static function rawbracket($q) {
+		return DB::raw(DB::bracket($q));
+	}
+	public static function rawvalue($str) {
+		return DB::raw(DB::value($str));
+	}
+	public static function rawtuple(array $vals) {
+		return DB::raw(DB::tuple($vals));
+	}
+	public static function call($fun, ...$args) {
+		return DB::raw("{$fun}(" . implode(',', array_map('DB::value', $args)) . ')');
+	}
+	public static function now() {
+		return DB::call('now');
+	}
+	public static function instr($str, $substr) {
+		return DB::call('instr', $str, $substr);
+	}
+	public static function cast_as_json($value) {
+		return DB::raw('cast(' . DB::value($value) . ' as json)');
+	}
+	public static function json_set($json_doc, ...$args) {
+		return DB::call('json_set', DB::raw($json_doc), ...$args);
+	}
+	public static function json_insert($json_doc, ...$args) {
+		return DB::call('json_insert', DB::raw($json_doc), ...$args);
+	}
+	public static function json_replace($json_doc, ...$args) {
+		return DB::call('json_replace', DB::raw($json_doc), ...$args);
+	}
+	public static function json_remove($json_doc, ...$args) {
+		return DB::call('json_remove', DB::raw($json_doc), ...$args);
+	}
+	public static function json_array_append($json_doc, ...$args) {
+		return DB::call('json_array_append', DB::raw($json_doc), ...$args);
+	}
+	public static function json_array_insert($json_doc, ...$args) {
+		return DB::call('json_array_insert', DB::raw($json_doc), ...$args);
+	}
+	public static function json_unquote($json_doc) {
+		return DB::call('json_unquote', DB::raw($json_doc));
+	}
 
 	public static function table($table) {
 		//return '`'.str_replace('`', '``', $table).'`';
 		return $table;
 	}
-    public static function fields($fields) {
-    	if (is_assoc($fields)) {
-    		$new_fields = [];
-    		foreach ($fields as $name => $val) {
-    			if (is_int($name)) {
-    				$new_fields[] = $val;
-    			} else {
-    				$new_fields[] = DB::field_as($val, $name);
-    			}
-    		}
-    		$fields = $new_fields;
-    	}
-    	return implode(',', $fields);
-    }
-    public static function bracketed_fields($fields) {
-    	return '('.DB::fields($fields).')';
-    }
-    public static function value($str) {
-    	if ($str === null) {
-    		return 'NULL';
-    	} elseif ($str === true) {
-    		return 'true';
-    	} elseif ($str === false) {
-    		return 'false';
-    	} elseif (is_int($str)|| is_float($str)) {
-    		return $str;
-    	} elseif (is_string($str)) {
-    		return '\''.DB::escape($str).'\'';
-    	} elseif ($str instanceof DBRawString) {
-    		return $str->str;
-    	} else {
-    		return false;
-    	}
-    }
-    public static function field_as($field, $name) {
-    	return "{$field} as {$name}";
-    }
-    public static function value_as($value, $name) {
-    	return DB::value($value)." as {$name}";
-    }
+	public static function fields($fields) {
+		if (is_assoc($fields)) {
+			$new_fields = [];
+			foreach ($fields as $name => $val) {
+				if (is_int($name)) {
+					$new_fields[] = $val;
+				} else {
+					$new_fields[] = DB::field_as($val, $name);
+				}
+			}
+			$fields = $new_fields;
+		}
+		return implode(',', $fields);
+	}
+	public static function bracketed_fields($fields) {
+		return '(' . DB::fields($fields) . ')';
+	}
+	public static function value($str) {
+		if ($str === null) {
+			return 'NULL';
+		} elseif ($str === true) {
+			return 'true';
+		} elseif ($str === false) {
+			return 'false';
+		} elseif (is_int($str) || is_float($str)) {
+			return $str;
+		} elseif (is_string($str)) {
+			return '\'' . DB::escape($str) . '\'';
+		} elseif ($str instanceof DBRawString) {
+			return $str->str;
+		} else {
+			return false;
+		}
+	}
+	public static function field_as($field, $name) {
+		return "{$field} as {$name}";
+	}
+	public static function value_as($value, $name) {
+		return DB::value($value) . " as {$name}";
+	}
 
-    public static function if_func($conds, $val1, $val2) {
-    	return 'if('.DB::conds($conds).','.DB::value($val1).','.DB::value($val2).')';
-    }
-    
-    public static function setValue($field, $val) {
-    	return $field.' = '.DB::value($val);
-    }
+	public static function if_func($conds, $val1, $val2) {
+		return 'if(' . DB::conds($conds) . ',' . DB::value($val1) . ',' . DB::value($val2) . ')';
+	}
+
+	public static function setValue($field, $val) {
+		return $field . ' = ' . DB::value($val);
+	}
 	public static function setValues(array $arr) {
 		$all = [];
 		foreach ($arr as $key => $val) {
@@ -152,16 +152,16 @@ class DB {
 				$lhs = $cond[0] instanceof DBRawString ? $cond[0]->str : $cond[0];
 				$op = $cond[1];
 				$rhs = DB::value($cond[2]);
-				return $lhs.' '.$op.' '.$rhs;
+				return $lhs . ' ' . $op . ' ' . $rhs;
 			} else {
 				return false;
 			}
 		}
 		return $cond;
 	}
-    public static function conds($conds) {
-    	return is_array($conds) ? DB::land($conds) : $conds;
-    }
+	public static function conds($conds) {
+		return is_array($conds) ? DB::land($conds) : $conds;
+	}
 	public static function land(array $conds) {
 		if (is_assoc($conds)) {
 			$new_conds = [];
@@ -178,7 +178,7 @@ class DB {
 			}
 			$conds = $new_conds;
 		}
-		return '('.implode(' and ', array_map('DB::cond', $conds)).')';
+		return '(' . implode(' and ', array_map('DB::cond', $conds)) . ')';
 	}
 	public static function lor(array $conds) {
 		if (is_assoc($conds)) {
@@ -196,7 +196,7 @@ class DB {
 			}
 			$conds = $new_conds;
 		}
-		return '('.implode(' or ', array_map('DB::cond', $conds)).')';
+		return '(' . implode(' or ', array_map('DB::cond', $conds)) . ')';
 	}
 	public static function tuple(array $vals) {
 		$str = '(';
@@ -212,20 +212,20 @@ class DB {
 		$str .= ')';
 		return $str;
 	}
-    public static function tuples(array $tuples) {
-    	$all = [];
-    	foreach ($tuples as $vals) {
-    		$all[] = DB::tuple($vals);
-    	}
-    	return implode(', ', $all);
-    }
-	
+	public static function tuples(array $tuples) {
+		$all = [];
+		foreach ($tuples as $vals) {
+			$all[] = DB::tuple($vals);
+		}
+		return implode(', ', $all);
+	}
+
 	public static function fetch($res, $opt = DB::ASSOC) {
 		return $res->fetch_array($opt);
 	}
 
 	public static function bracket($q) {
-		return '('.DB::query_str($q).')';
+		return '(' . DB::query_str($q) . ')';
 	}
 	public static function query_str($q) {
 		if (is_array($q)) {
@@ -257,11 +257,11 @@ class DB {
 		}
 		return $q;
 	}
-	
+
 	public static function exists($q) {
-		return 'exists '.DB::bracket($q);
+		return 'exists ' . DB::bracket($q);
 	}
-	
+
 	public static function query($q) {
 		return DB::$conn->query(DB::query_str($q));
 	}
@@ -269,7 +269,7 @@ class DB {
 		$ret = DB::$conn->query(DB::query_str($q));
 		if ($ret === false) {
 			UOJLog::error(DB::query_str($q));
-			UOJLog::error('update failed: '.DB::$conn->error);
+			UOJLog::error('update failed: ' . DB::$conn->error);
 		}
 		return $ret;
 	}
@@ -277,19 +277,19 @@ class DB {
 		$ret = DB::$conn->query(DB::query_str($q));
 		if ($ret === false) {
 			UOJLog::error(DB::query_str($q));
-			UOJLog::error('insert failed: '.DB::$conn->error);
+			UOJLog::error('insert failed: ' . DB::$conn->error);
 		}
 		return $ret;
 	}
 	public static function insert_id() {
 		return DB::$conn->insert_id;
 	}
-	
+
 	public static function delete($q) {
 		$ret = DB::$conn->query(DB::query_str($q));
 		if ($ret === false) {
 			UOJLog::error(DB::query_str($q));
-			UOJLog::error('delete failed: '.DB::$conn->error);
+			UOJLog::error('delete failed: ' . DB::$conn->error);
 		}
 		return $ret;
 	}
@@ -323,7 +323,7 @@ class DB {
 			return false;
 		}
 		// return $qres->fetch_all($opt);   not supported
-        
+
 		$res = [];
 		while ($row = $qres->fetch_array($opt)) {
 			$res[] = $row;
@@ -337,21 +337,21 @@ class DB {
 		}
 		return $res->fetch_array($opt);
 	}
-    public static function selectSingle($q) {
-    	$res = DB::select($q);
-    	if ($res === false) {
-    		return false;
-    	}
-    	$row = $res->fetch_row();
-    	if (!$row) {
-    		return false;
-    	}
-    	return $row[0];
-    }
+	public static function selectSingle($q) {
+		$res = DB::select($q);
+		if ($res === false) {
+			return false;
+		}
+		$row = $res->fetch_row();
+		if (!$row) {
+			return false;
+		}
+		return $row[0];
+	}
 
-    /**
-     * perform SQL query $q in the form of select count(*) from XXX where XXX;
-    */
+	/**
+	 * perform SQL query $q in the form of select count(*) from XXX where XXX;
+	 */
 	public static function selectCount($q) {
 		$res = DB::select($q);
 		if ($res === false) {
@@ -361,87 +361,87 @@ class DB {
 		return $cnt;
 	}
 
-    /**
+	/**
 	 * perform SQL query: select exists ($q);
 	 * 
 	 * on success, returns 0 or 1
 	 * on failure, returns false
 	 * 
 	 * @return int|false
-	*/
-    public static function selectExists($q) {
-    	$res = DB::select(["select", DB::exists($q)]);
-    	if ($res === false) {
-    		return false;
-    	}
-    	return (int)($res->fetch_row()[0]);
-    }
-    
-    public static function limit() {
-    	$num = func_get_args();
-    	if (count($num) == 1) {
-    		return "limit ".((int)$num[0]);
-    	} elseif (count($num) == 2) {
-    		return "limit ".((int)$num[0]).",".((int)$num[1]);
-    	} else {
-    		return false;
-    	}
-    }
+	 */
+	public static function selectExists($q) {
+		$res = DB::select(["select", DB::exists($q)]);
+		if ($res === false) {
+			return false;
+		}
+		return (int)($res->fetch_row()[0]);
+	}
 
-    public static function for_share() {
-    	return "for share";
-    }
-    public static function for_update() {
-    	return "for update";
-    }
+	public static function limit() {
+		$num = func_get_args();
+		if (count($num) == 1) {
+			return "limit " . ((int)$num[0]);
+		} elseif (count($num) == 2) {
+			return "limit " . ((int)$num[0]) . "," . ((int)$num[1]);
+		} else {
+			return false;
+		}
+	}
 
-    public static function startTransaction() {
-    	return DB::$conn->begin_transaction();
-    }
+	public static function for_share() {
+		return "for share";
+	}
+	public static function for_update() {
+		return "for update";
+	}
 
-    public static function rollback() {
-    	return DB::$conn->rollback();
-    }
+	public static function startTransaction() {
+		return DB::$conn->begin_transaction();
+	}
 
-    public static function commit() {
-    	return DB::$conn->commit();
-    }
+	public static function rollback() {
+		return DB::$conn->rollback();
+	}
+
+	public static function commit() {
+		return DB::$conn->commit();
+	}
+
+	public static function transaction($func) {
+		if (DB::$in_transaction) {
+			$ret = $func();
+		} else {
+			DB::$in_transaction = true;
+			DB::startTransaction();
+			$ret = $func();
+			DB::commit();
+			DB::$in_transaction = false;
+		}
+		return $ret;
+	}
 
-    public static function transaction($func) {
-    	if (DB::$in_transaction) {
-    		$ret = $func();
-    	} else {
-    		DB::$in_transaction = true;
-    		DB::startTransaction();
-    		$ret = $func();
-    		DB::commit();
-    		DB::$in_transaction = false;
-    	}
-    	return $ret;
-    }
-	
 	public static function lock($tables, $func) {
 		$q = [];
 		foreach ($tables as $table => $type) {
 			if ($type != DB::WLOCK && $type != DB::RLOCK) {
-				UOJLog::error('Unknown type: '.$type);
+				UOJLog::error('Unknown type: ' . $type);
 				return false;
 			}
-			$q[] = $table.' '.$type;
+			$q[] = $table . ' ' . $type;
 		}
-		$q = 'lock tables '.implode(',', $q);
+		$q = 'lock tables ' . implode(',', $q);
 		DB::query($q);
-		
+
 		$ret = $func();
-		
+
 		DB::query("unlock tables");
-		
+
 		return $ret;
 	}
 	public static function checkTableExists($name) {
 		return DB::select(["select 1 from", DB::table($name)]) !== false;
 	}
-	
+
 	public static function num_rows($res) {
 		return $res->num_rows;
 	}
diff --git a/web/app/models/UOJContest.php b/web/app/models/UOJContest.php
index 773f6d8..5a21f2e 100644
--- a/web/app/models/UOJContest.php
+++ b/web/app/models/UOJContest.php
@@ -191,114 +191,127 @@ class UOJContest {
 		ignore_user_abort(true);
 		set_time_limit(0);
 
-		DB::update([
-			"update contests",
-			"set", ["status" => 'testing'],
-			"where", ["id" => $this->info['id']]
-		]);
-
-		if (DB::affected_rows() !== 1) {
-			// 已经有其他人开始评测了，不进行任何操作
-			return;
-		}
-
-		$res = DB::selectAll([
-			"select id, problem_id, content, result, submitter, hide_score_to_others from submissions",
-			"where", ["contest_id" => $this->info['id']]
-		]);
-		foreach ($res as $submission) {
-			$content = json_decode($submission['content'], true);
-
-			if (isset($content['final_test_config'])) {
-				$content['config'] = $content['final_test_config'];
-				unset($content['final_test_config']);
-			}
-
-			if (isset($content['first_test_config'])) {
-				unset($content['first_test_config']);
-			}
-
-			$q = [
-				'content' => json_encode($content),
-			];
-
-			$problem_judge_type = $this->info['extra_config']["problem_{$submission['problem_id']}"] ?: $this->defaultProblemJudgeType();
-			$result = json_decode($submission['result'], true);
-
-			switch ($problem_judge_type) {
-				case 'sample':
-					if (isset($result['final_result']) && $result['final_result']['status'] == 'Judged') {
-						$q += [
-							'result' => json_encode($result['final_result']),
-							'score' => $result['final_result']['score'],
-							'used_time' => $result['final_result']['time'],
-							'used_memory' => $result['final_result']['memory'],
-							'judge_time' => $this->info['end_time_str'],
-							'status' => 'Judged',
-						];
-
-						if ($submission['hide_score_to_others']) {
-							$q['hidden_score'] = $q['score'];
-							$q['score'] = null;
-						}
-					}
-
-					break;
-
-				case 'no-details':
-				case 'full':
-					if ($result['status'] == 'Judged' && !isset($result['final_result'])) {
-						$q += [
-							'result' => $submission['result'],
-							'score' => $result['score'],
-							'used_time' => $result['time'],
-							'used_memory' => $result['memory'],
-							'judge_time' => $this->info['end_time_str'],
-							'status' => 'Judged',
-						];
-
-						if ($submission['hide_score_to_others']) {
-							$q['hidden_score'] = $q['score'];
-							$q['score'] = null;
-						}
-					}
-
-					break;
-			}
-
-			UOJSubmission::rejudgeById($submission['id'], [
-				'reason_text' => HTML::stripTags($this->info['name']) . ' 最终测试',
-				'reason_url' => HTML::url(UOJContest::cur()->getUri()),
-				'set_q' => $q,
+		DB::transaction(function () {
+			$status = DB::selectSingle([
+				"select status from contests",
+				"where", ["id" => $this->info['id']],
+				DB::for_update(),
 			]);
-		}
 
-		// warning: check if this command works well when the database is not MySQL
-		DB::update([
-			"update submissions",
-			"set", [
-				"score = hidden_score",
-				"hidden_score = NULL",
-				"hide_score_to_others = 0"
-			], "where", [
-				"contest_id" => $this->info['id'],
-				"hide_score_to_others" => 1
-			]
-		]);
+			if ($status !== 'unfinished') {
+				// 已经有其他人开始评测了，不进行任何操作
+				return;
+			}
 
-		$updated = [];
-		foreach ($res as $submission) {
-			$submitter = $submission['submitter'];
-			$pid = $submission['problem_id'];
-			if (isset($updated[$submitter]) && isset($updated[$submitter][$pid])) {
-				continue;
+			$res = DB::selectAll([
+				"select id, problem_id, content, result, submitter, hide_score_to_others from submissions",
+				"where", ["contest_id" => $this->info['id']],
+				DB::for_update(),
+			]);
+			foreach ($res as $submission) {
+				$content = json_decode($submission['content'], true);
+
+				if (isset($content['final_test_config'])) {
+					$content['config'] = $content['final_test_config'];
+					unset($content['final_test_config']);
+				}
+
+				if (isset($content['first_test_config'])) {
+					unset($content['first_test_config']);
+				}
+
+				$q = [
+					'content' => json_encode($content),
+				];
+
+				$problem_judge_type = $this->info['extra_config']["problem_{$submission['problem_id']}"] ?: $this->defaultProblemJudgeType();
+				$result = json_decode($submission['result'], true);
+
+				switch ($problem_judge_type) {
+					case 'sample':
+						if (isset($result['final_result']) && $result['final_result']['status'] == 'Judged') {
+							$q += [
+								'result' => json_encode($result['final_result']),
+								'score' => $result['final_result']['score'],
+								'used_time' => $result['final_result']['time'],
+								'used_memory' => $result['final_result']['memory'],
+								'judge_time' => $this->info['end_time_str'],
+								'status' => 'Judged',
+							];
+
+							if ($submission['hide_score_to_others']) {
+								$q['hidden_score'] = $q['score'];
+								$q['score'] = null;
+							}
+						}
+
+						break;
+
+					case 'no-details':
+					case 'full':
+						if ($result['status'] == 'Judged' && !isset($result['final_result'])) {
+							$q += [
+								'result' => $submission['result'],
+								'score' => $result['score'],
+								'used_time' => $result['time'],
+								'used_memory' => $result['memory'],
+								'judge_time' => $this->info['end_time_str'],
+								'status' => 'Judged',
+							];
+
+							if ($submission['hide_score_to_others']) {
+								$q['hidden_score'] = $q['score'];
+								$q['score'] = null;
+							}
+						}
+
+						break;
+				}
+
+				UOJSubmission::rejudgeById($submission['id'], [
+					'reason_text' => HTML::stripTags($this->info['name']) . ' 最终测试',
+					'reason_url' => HTML::url(UOJContest::cur()->getUri()),
+					'set_q' => $q,
+				]);
 			}
-			updateBestACSubmissions($submitter, $pid);
-			if (!isset($updated[$submitter])) {
-				$updated[$submitter] = [];
+
+			// warning: check if this command works well when the database is not MySQL
+			DB::update([
+				"update submissions",
+				"set", [
+					"score = hidden_score",
+					"hidden_score = NULL",
+					"hide_score_to_others = 0"
+				], "where", [
+					"contest_id" => $this->info['id'],
+					"hide_score_to_others" => 1
+				]
+			]);
+
+			$updated = [];
+			foreach ($res as $submission) {
+				$submitter = $submission['submitter'];
+				$pid = $submission['problem_id'];
+				if (isset($updated[$submitter]) && isset($updated[$submitter][$pid])) {
+					continue;
+				}
+				updateBestACSubmissions($submitter, $pid);
+				if (!isset($updated[$submitter])) {
+					$updated[$submitter] = [];
+				}
+				$updated[$submitter][$pid] = true;
 			}
-			$updated[$submitter][$pid] = true;
-		}
+
+			DB::update([
+				"update contests",
+				"set", [
+					"status" => "testing",
+				],
+				"where", [
+					"id" => $this->info['id'],
+				],
+			]);
+		});
 	}
 
 	public function queryJudgeProgress() {
diff --git a/web/app/models/UOJSubmission.php b/web/app/models/UOJSubmission.php
index be20cd6..f556f93 100644
--- a/web/app/models/UOJSubmission.php
+++ b/web/app/models/UOJSubmission.php
@@ -359,7 +359,7 @@ class UOJSubmission {
 								])
 							])
 						], DB::for_update()
-					]);
+					]);	
 					DB::update(["update submissions", "set", $cfg['set_q'], "where", [$cond]]);
 				});
 			} else {
diff --git a/web/app/upgrade/14_sync_from_uoj.ac/up.sql b/web/app/upgrade/14_sync_from_uoj.ac/up.sql
index 8d69501..31a84f5 100644
--- a/web/app/upgrade/14_sync_from_uoj.ac/up.sql
+++ b/web/app/upgrade/14_sync_from_uoj.ac/up.sql
@@ -1,5 +1,7 @@
 -- InnoDB
 ALTER TABLE `best_ac_submissions` ENGINE=InnoDB TABLESPACE `innodb_system`;
+ALTER TABLE `contests` ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+ALTER TABLE `contests_submissions` ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
 ALTER TABLE `judger_info` COLLATE=utf8mb4_unicode_ci;
 ALTER TABLE `problems_contents` COLLATE=utf8mb4_unicode_ci;
 ALTER TABLE `submissions` ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;