SLT Real Time Data Replication From ECC

Hi Tech Gurus,

I need to replicate data from SAP BW system to HANA DB. As there was historical data present in BW Cubes How the SLT Real time data replication works to Pull data from ECC tables when there is an already Historical data present for the same tables in BW Cubes. so i need to know how can we move all the historical data present in the underlying tables without duplicates using SLT Data provisioning.