WordpressでError establishing a database connection

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MySQLに接続してみたらエラー

$ mysql -u XXXXX
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (111 "Connection refused")

原因を調べる
serverfault.com

$ service mysqld status
Redirecting to /bin/systemctl status mysqld.service
● mariadb.service - MariaDB 10.1.48 database server
   Loaded: loaded (/usr/lib/systemd/system/mariadb.service; enabled; vendor preset: disabled)
  Drop-In: /etc/systemd/system/mariadb.service.d
           └─migrated-from-my.cnf-settings.conf
   Active: failed (Result: exit-code) since 金 2024-07-19 13:42:01 JST; 1 weeks 5 days ago

２週間前からMariaDBが落ちていたらしい

Maria DBを再起動したら復旧した

$ sudo systemctl start mariadb.service

$ service mysqld status
Redirecting to /bin/systemctl status mysqld.service
● mariadb.service - MariaDB 10.1.48 database server
   Loaded: loaded (/usr/lib/systemd/system/mariadb.service; enabled; vendor preset: disabled)
  Drop-In: /etc/systemd/system/mariadb.service.d
           └─migrated-from-my.cnf-settings.conf
   Active: active (running) since 水 2024-07-31 15:20:15 JST; 5s ago