我已在测试服务器上将MySQL 8.0.3更新为8.0.4。但是，它不会启动该服务。
LOG的附加信息：
2018-01-24T04:32:26.996977Z 0 [System] [MY-010116] /usr/sbin/mysqld (mysqld 8.0.4-rc-log) starting as process 12406 ...
2018-01-24T04:32:27.444234Z 1 [ERROR] [MY-011096] No data dictionary version number found.
2018-01-24T04:32:27.444725Z 0 [ERROR] [MY-010020] Data Dictionary initialization failed.
2018-01-24T04:32:27.444802Z 0 [ERROR] [MY-010119] Aborting
2018-01-24T04:32:28.806928Z 0 [System] [MY-010910] /usr/sbin/mysqld: Shutdown complete.
我也尝试运行mysqld_safe，它会抛出以下内容：
2018-01-24T04: 25: 33.852181Z mysqld_safe Logging to '/var/log/mysql/error.log'.
2018-01-24T04: 25: 33.857404Z mysqld_safe Directory '/var/run/mysqld' for UNIX socket file do not exists.
目录不存在所以我继续创建它：
sudo mkdir -p /var/run/mysqld
sudo chown mysql: mysql /var/run/mysqld
sudo mysqld_safe
他在控制台抛出以下内容：
2018-01-24T04：27：29.816902Z mysqld_safe记录到'/var/log/mysql/error.log'。 2018-01-24T04：27：29.870025Z mysqld_safe使用/ var / lib / mysql中的数据库启动mysqld守护程序 nohup / usr / sbin / mysqld --basedir = / usr --datadir = / var / lib / mysql --plugin-dir = / usr / lib / mysql / plugin --user = mysql --log-error = / var /log/mysql/error.log --pid-file = / var / run / mysqld / mysqld.pid --socket = / var / run / mysqld / mysqld.sock --port = 3309
我再次开始服务并抛弃我：
Job for mysql.service failed because of the control process exited with error code. See "systemctl status mysql.service" and "journalctl -xe" for details.
我搜索日志，然后出现以下内容：
2018-01-24T04: 30: 11.601843Z 0 [System] [MY-010116] /usr/sbin/mysqld (mysqld 8.0.4-rc-log) starting as process 9140 ...
2018-01-24T04: 30: 12.001705Z 1 [ERROR] [MY-011096] No data dictionary version number found.
2018-01-24T04: 30: 12.002121Z 0 [ERROR] [MY-010020] Data Dictionary initialization failed.
2018-01-24T04: 30: 12.002232Z 0 [ERROR] [MY-010119] Aborting
我该怎么做才能启动这项服务？我查看了/ var / lib / mysql目录，还有数据库。