MySQL cannot be started after Ubuntu is upgraded to 10.04.

After upgrading Ubuntu to 10.04, the following error occurs when connecting to mysql: Can 'tconnecttolocalmysqlserverthroughsocket '/var/run/mysqld. sock'. mysql is not started. The execution of sudostartmysql cannot be started and there is no response. Startmysql cannot be started. The following message is displayed: start: Rejectedsendmes.

After upgrading Ubuntu to 10.04, the following error occurs when connecting to mysql:
Can't connect to local MySQL server through socket '/var/run/mysqld. sock'

After reading this, mysql is not started. Run
Sudo start mysql
Unable to start, no response.
Start mysql
Unable to start. The following message is displayed:
Start: Rejected send message, 1 matched rules; type = "method_call", sender = ": 1.80" (uid = 1000 pid = 14704 comm = "restart) interface =" com. ubuntu. upstart0_6.Job "member =" Restart "error name =" (unset) "requested_reply = 0 destination =" com. ubuntu. upstart "(uid = 0 pid = 1 comm ="/sbin/init "))

Start directly:
Sudo-u mysql mysqld
Prompt:
Mysqld: Table 'mysql. plugin 'doesn' t exist
100508 9:08:53 [ERROR] Can't open the mysql. plugin table. Please run mysql_upgrade to create it.
100508 9:08:54 InnoDB: Started; log sequence number 0 14859112
100508 9:08:54 [ERROR] mysqld: unknown option '-- skip-bdb'
100508 9:08:54 [ERROR] Aborting

Edit/etc/mysql/my. cnf, locate-skip-bdb, and comment out the line. Then run sudo-u mysql mysqld or sudo start mysql to start the mysql smoothly.

Follow the prompts to upgrade:
Mysql_upgrade-p