Which two statements are true about the Global Enqueue Service, Instance Locks, and global enqueues in Oracle 12c RAC? 

Answer options:

A. In a RAC One Node database, there is no LMD0 process if only one instance is running.
B. Global Enqueues and Instance Locks replace mutexes completely in RAC database instances.
C. In a RAC database, there is no LMD0 process if only one instance is running.
D. Global Enqueues and Instance Locks replace latches completely in RAC database instances.
E. Global Enqueues may have owners and waiters in the same instance.
F. Global Enqueues may have converters and waiters in the same instance.

AF

F: A convert queue is a queue of locks that are waiting to be converted to particular mode, this is the process of changing a lock from one mode to another, even a NULL is a lock. A resource has a lock value block (LVB). The Global Resource Manager (GRM) keeps the lock information valid and correct across the cluster. Oracle 10g release 2 and beyond replaced some latch mechanisms with the mutex approach, claiming that they are faster and more efficient than traditional locking mechanisms. Incorrect Answers: B, D: Mutexes are objects that exist within the operating system to provide access to shared memory structures. They are similar to latches. References: http://www.datadisk.co.uk/html_docs/rac/grd.htm