How I dealt with having to delete 1.3 million SPAM registrations

[hugh_]

After moving this site to a host with cron access I cleaned up a remaining 165k spam registrations with a scheduled task run one minute before and the following job. 175 users was the most the server could delete at one time but your millage may vary.

9,19,29,39,49,59 * * * * /usr/bin/mysql -u root -p<MYSQLPASSWORD> -e "USE <DBNAME>;UPDATE user set usergroupid = <DELETIONGROUP> where usergroupid = <SPAMGROUP> LIMIT 175" > /dev/null 2>&1