Spool space issue - response (5) by dnoeth

According to Standard SQL FROM is processed before WHERE in theory, but all optimizers try to push the WHERE-conditions into the join, thus they're are practically done before or during the join (this might be different for some conditions in Outer joins).
 
Spool is calculated on a user level, not on session level.
Each queriy might fit into the user's spool, but could fail if the same user runs multiple queries in different sessions concurrently.