Thanks Miruna.

I did some looking around in the meantime, and found the following tables appear to have records related to the instance history:

dbo.search_activity_messages

dbo.search_activity_messages_log

dbo.search_activity

dbo.search_activity_log

dbo.search_entry

dbo.search_entry_log

dbo.search_instance

dbo.search_instance_log

Are you saying that the tables without the *_log above in the name are not included in maintaining history for the instances.

Thanks!

That's correct. The ones without _Log contain info on running instances. As an instance is completed, its history gets moved from the "live" table to their corresponding _Log equivalent and kept there for 30 days (or however long the lifetime specified is).