可重复读取和锁定兼容性表

Question

我想我已经理解了这个问题的答案：

Repeatable Read - am I understanding this right?

但我对可重复的阅读场景有一个补充问题。 据说：

重复阅读

1 SELECT -- places a shared lock and keeps it
2 UPDATE -- tries to places an exclusive lock but it's not compatible with the shared lock. Locks
1 SELECT -- the lock is already placed. Succeeds.

但如果更新是由事务1进行的呢？是否因为不兼容的锁而被阻止？