We are currently in the process of migrating a large customer (350 users) from 8.0 SR4 Windows to 8.5 R7 Web.
They have been an long time customer and currently have 155k records in the userpreference table. We noticed during testing that the initial load times of the web & admin client, especially the preferences section, takes a very long time. The slow query log shows that the userpreferences query takes a long time. (it loads all 155k records).
After cleaning up all userpreferences of associates that have been long retired, we have 49k records left. The initial load times of the web & admin client are a lot faster now.
Of those 49k records, 15k are 'liveupdate' prefkeys. Is it safe to delete these prefkeys? As far as I know these are windows client specific, which they don't use anymore.