Today we do not support BigFix Insights ingesting from a DB2 core. This is something we are exploring, but there are no hard timeframes associated at this point.
I can say at this point SQL 2017 is the minimum version, 2019 has not been qualified for the platform (BFE) although i believe that is planned , although I cant state timeframes there. Once BFE is qualified to 2019 , I think Insights will follow shortly.
Assuming you had a MS SQL BFE, we do not support ingesting from a live BFE source at this point (to mitigate the impact to BFE core operations). Typically customers have a backup methodology in place, and insights is designed to leverage the backup as the BFE dataource (this copy of the BFE database) is conveyed as the replica requirement. In general you should not allow insights to ingest from a live BFE datasource.