Unable to delete host

[ben.bressler]

When I try to delete a host I get this error message. I tried rebooting the zabbix server but keep getting the same error.

Error in query [DELETE FROM graphs WHERE (graphid IN ('398','445','492','539')) ] [Lock wait timeout exceeded; try restarting transaction]
SQL statement execution has failed "DELETE FROM graphs WHERE (graphid IN ('398','445','492','539')) "

[BDiE8VNy]

Most times when I was faced with such locks it was caused by concurrent access.
Have you tried to leave the server stopped and if the lock still occurs to additionally enable Frontend maintenance mode

[heaje]

That looks like a MySQL error, so I assume your DB is using MySQL. Have you tried logging into MySQL and running "show processlist" to see if there are queries that are stuck that are locking your DB? Also, have you tried restarting MySQL to see if that makes the issue go away?