The Phantom Phantom Problem
It looks like T1 should lock record 4, which isn’t there!
Which of T1’s operations determined that there were only 3 records?
- Read end-of-file?
- Read record counter?
- SQL Select operation?
This operation conflicts with T2’s Insert Accounts[4,Tacoma,100]
Therefore, Insert Accounts[4,Tacoma,100] shouldn’t run until after T1 commits