We had an issue, the DTA database was empty, nothing was being tracked, and we were seeing a weird error message that pointed at something else in the event log:
Either another TDDS is processing the same data or there is an orphaned session in SQL server holding TDDS lock. Either another TDDS is processing the same data or there is an orphaned session in SQL Server holding TDDS lock. SQL Server: \. Database: BizTalkDTADb