I asked my I-485 status and he looked up in the database, and I think he was seriously and did it, then told me my case is under name check, waiting for process. I complained that my H-1B already went through very strict background check (RFE requested some orignial documents from me) and why I have to go through this again? He said the name check is done by FBI and asked me to contact FBI.
My feeling is: talking to the officer is just equivalent to go for infopass, nothing would change except knowing a bit about where you are.
Good luck for everyone here!