Hello Tamas,
yes, you can have real-time replication. SLT can be used for non-sap source like oracle DB. replication works in the same way as SAP source system - but table structure changes (like adding or removing table/column) also known metadata stored in DD02L & DD02T will be loaded as initial load and will not be replicated, below OSS note as report which will allow you to update the tables.
1751323 - Hana LTR : Non Sap Replication-Update DD02L and DD02T tables
All the table content changes (even table truncate and inserts) will be logged in the logging table and can be replicated to target system in real-time or scheduled by time . There are many guides and scn docs on this subject, here are some:
1768805 - SAP LT Replication Server: Collective Note - non-SAP Sources
http://help.sap.com/hana/SAP_Landscape_Transformation_for_SAP_HANA_Operations_Guide_en.pdf
All the Best !
-Prashanth