-- mass e-mail: own sending rate, optional address check, pause / cancel, counts of skipped and failed addresses
ALTER TABLE mass_mails
  ADD per_minute INT UNSIGNED NOT NULL DEFAULT 60,
  ADD verify TINYINT(1) NOT NULL DEFAULT 0,
  ADD status VARCHAR(10) NOT NULL DEFAULT 'sending' COMMENT 'sending|paused|done|cancelled',
  ADD invalid INT UNSIGNED NOT NULL DEFAULT 0,
  ADD failed INT UNSIGNED NOT NULL DEFAULT 0,
  ADD finished_at DATETIME NULL;
UPDATE mass_mails SET status = IF(sent >= total, 'done', 'sending');
ALTER TABLE mail_queue ADD note VARCHAR(100) NOT NULL DEFAULT '' COMMENT 'why invalid / failed';