SELECT query, row versioning and TempDb

Hi All,

I am on SQL Server 2008.

I want to clear my concept about row versioning and usage of TempDb. In my database, read committed snapshot is ON. Now lets say, session1 is updating some data in TABLE1. My understanding is, session1 will store its own version of updated rows in TempDb. Effectively TempDb used by session1 will increase.

Now, while session1 is updating TABLE1, session2 try to read data from TABLE1, which is being updated from session1. Because session1 has kept its updated rows in saperate place, session2 can read data without any problems.

My question is, the session which is reading data, session2 in this case, does it need to use any TempDb (because of the row versioning)? Are there any gaps in my understanding?

Thanks in advance