Other components of the Shared Pool

Enqueues are shared memory structures that are used as locks to serialize access to database resources.

They can be associated with a session or transaction.

Some usages of Enqueues are

• Controlfile Transaction
• Datafile
• Instance Recovery
• Media Recovery
• Transaction Recovery
• Job Queue
• etc.

Latches low-level serialization control primitives. They protect shared data structures in the SGA from simultaneous access.

Areas where latches are used include

• e row cache objects
• library cache pin
• log file parallel write