openstack (havana) nova: instance in error state cleanup script

instance_cleanup.sh

#!/bin/bash

echo "Enter your MySQL user"
read MYSQL_USER

echo "Enter your MySQL user password"
read MYSQL_PASSWD

echo "Enter your MySQL host"
read MYSQL_HOST

mysql -u$MYSQL_USER -p$MYSQL_PASSWD -h$MYSQL_HOST -e 'USE nova; DELETE FROM security_group_instance_association WHERE instance_uuid IN (SELECT uuid FROM instances WHERE vm_state = "error");'
mysql -u$MYSQL_USER -p$MYSQL_PASSWD -h$MYSQL_HOST -e 'USE nova; DELETE FROM block_device_mapping WHERE instance_uuid IN (SELECT uuid FROM instances WHERE vm_state = "error");'
mysql -u$MYSQL_USER -p$MYSQL_PASSWD -h$MYSQL_HOST -e 'USE nova; DELETE FROM instance_info_caches WHERE instance_uuid IN (SELECT uuid FROM instances WHERE vm_state = "error");'
mysql -u$MYSQL_USER -p$MYSQL_PASSWD -h$MYSQL_HOST -e 'USE nova; DELETE FROM instance_system_metadata WHERE instance_uuid IN (SELECT uuid FROM instances WHERE vm_state = "error");'
mysql -u$MYSQL_USER -p$MYSQL_PASSWD -h$MYSQL_HOST -e 'USE nova; DELETE FROM instance_faults WHERE instance_uuid IN (SELECT uuid FROM instances WHERE vm_state = "error");'
mysql -u$MYSQL_USER -p$MYSQL_PASSWD -h$MYSQL_HOST -e 'USE nova; DELETE FROM instance_actions_events WHERE action_id IN (SELECT id FROM instance_actions where instance_uuid IN (SELECT uuid FROM instances WHERE vm_state = "error"));'
mysql -u$MYSQL_USER -p$MYSQL_PASSWD -h$MYSQL_HOST -e 'USE nova; DELETE FROM instance_actions WHERE instance_uuid IN (SELECT uuid FROM instances WHERE vm_state = "error");'
mysql -u$MYSQL_USER -p$MYSQL_PASSWD -h$MYSQL_HOST -e 'USE nova; UPDATE fixed_ips SET allocated = 0 WHERE instance_uuid IN (SELECT uuid FROM instances WHERE vm_state = "error");'
mysql -u$MYSQL_USER -p$MYSQL_PASSWD -h$MYSQL_HOST -e 'USE nova; DELETE FROM instances WHERE vm_state = "error";'