disconnecting clients

MySQL & MariaDB Percona Server for MySQL 5.6
1

[Note] Forcefully disconnecting 5 remaining clients
[Warning] /usr/sbin/mysqld: Forcing close of thread 1229 user: ‘b_user’
[Warning] /usr/sbin/mysqld: Forcing close of thread 1231 user: ‘b_user’
[Warning] /usr/sbin/mysqld: Forcing close of thread 1228 user: ‘b_user’
[Warning] /usr/sbin/mysqld: Forcing close of thread 1273 user: ‘b_user’
[Warning] /usr/sbin/mysqld: Forcing close of thread 1270 user: ‘b_user’

why is this happening?

2

Looks like MySQL is in a shutdown phase. Check if someone sent a shutdown signal to the MySQL server.