Is there a best practice for removing old historian tables? I have a lot of old tables that contain data we no longer use. I would like to clean up the database and remove them, but I'm not sure if simply deleting the tables will cause any problems. These are the 'dbo.sqlt_data...' tables.
See "data pruning" in Tag History Providers - Ignition User Manual 8.1 - Ignition Documentation.
Modify the historian setting to prune back before a certain age, wait for it to operate (I can't remember when this occurs), and then set the pruning back to a longer time, if required. This will have Ignition controlling the pruning and may be safer than you (or me) going mucking about.
I believe deleting those tables should be pretty safe, though you should probably also remove the corresponding record in sqlth_partitions.
But frankly, automatic pruning is probably the way to go.
Looks like it happens every 10 minutes but I wasn't able to find if it's on a fixed schedule or just starting from when pruning is enabled.