The thread_read is part of the XF Daily Clean Up cron entry I think. Not really a good idea to disable it. You'll probably just have to set your "Read Marking Data Lifetime (Days)" (Home -> Options -> Threads, Discussions and Conversations) to a much higher number than the default of 30. Assuming you set it to 365, one year later your thread_read data that is older than one year would still be wiped so you'd need to set it to something monstrously high. This is probably not a good idea for big boards though.Where are the settings to purge the thread_read tables controlled?