Hi Hirdesh,
We have successfully used HANA Sidecar and the only thing I can add to Sharan's comments is one of our challenges around code review. For example on the HANA side of things we have code reviews for any new models that are delivered however sidecar queries that are written in SAP ABAP could potentially be changed and we could lose visibility. For example say we approved a sidecar query to pull 10 fields from a table in HANA. Everything is great and they are consuming lets say a gigabyte of memory. Then a year from now somebody on the ABAP side decides they want to change their query and bump it to 20 fields. This is a simple example but you can see they could suddenly be consuming more of HANA memory than originally intended. So for this reason it's important to somehow have cross-functional code reviews so that the HANA team is always aware of what could be changing at the sidecar level.
That's my little tidbit, I hope it helps.
-Patrick
