install plugin feedback soname 'feedback.so';
select plugin_status from information_schema.plugins where plugin_name='feedback';
plugin_status
ACTIVE
select * from information_schema.feedback where variable_name like 'feed%'
       and variable_name not like  '%_uid'
       and variable_name not like '%debug%';
VARIABLE_NAME	VARIABLE_VALUE
FEEDBACK used	2
FEEDBACK version	1.1
FEEDBACK_HTTP_PROXY	
FEEDBACK_SEND_RETRY_WAIT	60
FEEDBACK_SEND_TIMEOUT	60
FEEDBACK_URL	http://mariadb.org/feedback_plugin/post
FEEDBACK_USER_INFO	mysql-test
uninstall plugin feedback;