API exception occurs because of Lock wait timeout exceeded in sql transaction in Red Hat OpenStack Platform

Issue

Openstack services show error messages with:

DBDeadlock: (pymysql.err.InternalError) (1205, u'Lock wait timeout exceeded; try restarting transaction

For example, an error message for nova could be:

ERROR nova.api.openstack.wsgi [----] Unexpected exception in API method: DBDeadlock: (pymysql.err.InternalError) (1205, u'Lock wait timeout exceeded; try restarting transaction') [SQL: u'UPDATE instance_extra SET updated_at=%(updated_at)s, flavor=%(flavor)s WHERE instance_extra.deleted = %(deleted_1)s AND instance_extra.instance_uuid = %(instance_uuid_1)s']