SQL BackEnd Clarification

[David T.]

I have yet to use the SQL back end with GnuCash, but in following the many discussions on the lists (both users and devel), I have read seemingly contradictory statements about the nature of data storage with the SQL back end. 
 
Specifically, at times we are told that GnuCash loads the entire SQL database into memory, and that simultaneous access to the same data file by multiple users will fail because GnuCash writes out the entire database upon closing. However, at other times, we are told that the Save button is never activated with the SQL back end because the changes are saved to the SQL back end immediately.
 
Could someone explain this apparent paradox to me?
 
David