New background processes in DB12c

Name	Expanded Name	Description	External Properties
AQPC	AQ Process Coordinator	AQPC is responsible for performing administrative tasks for AQ Master Class Processes including commands like starting, stopping, and other administrative tasks. This process is automatically started on instance startup.	Database instances Advanced Queueing
ARSn	ASM Recovery Slave Process	The ASM RBAL background process coordinates and spawns one or more of these slave processes to recover aborted ASM transactional operations. These processes run only in the Oracle ASM instance.	Oracle ASM instances
BWnn	Database Writer Process	See the Description for the DBWn process in this table for more information about the BWnn process.	Database instances
FENC	Fence Monitor Process	CSS monitors RDBMS instances which are connected to the Oracle ASM instance and constantly doing I/Os. When the RDBMS instance terminates due to a failure, all the outstanding I/O’s from the RDBMS instance should be drained and any new I/O’s rejected. FENC receives and processes the fence request from CSSD.	Oracle ASM instances
GCRn	Global Conflict Resolution Slave Process	GCRn processes are transient slaves that are started and stopped as required by LMHB to perform synchronous or resource intensive tasks.	Database instances, Oracle ASM instances, Oracle RAC
IPC0	IPC Service Background Process	IPC0 handles very high rates of incoming connect requests, as well as, completing reconfigurations to support basic messaging and RDMA primitives over several transports such as UDP, RDS, InfiniBand and RC.	Oracle RAC
LDDn	Global Enqueue Service Daemon Helper Slave	LDDn processes are slave processes spawned on demand by LMDn processes. They are spawned to help the dedicated LMDn processes with various tasks when certain workloads start creating performance bottlenecks. These slave processes are transient as they are started on demand and they can be shutdown when no longer needed. There can be up to 36 of these slave processes (LDD0-LDDz).	Database instances, Oracle ASM instances, Oracle RAC
LGnn	Log Writer Worker	On multiprocessor systems, LGWR creates worker processes to improve the performance of writing to the redo log. LGWR workers are not used when there is a SYNC standby destination. Possible processes include LG00-LG99.	Database instances
LREG	Listener Registration Process	LREG notifies the listeners about instances, services, handlers, and endpoint.	Database instances, Oracle ASM instances, Oracle RAC
OFSD	Oracle File Server Background Process	This background process listens for new file system requests, both management (like mount, unmount, and export) and I/O requests, and executes them using Oracle threads.	Database instances, Oracle RAC
QMnn	AQ Master Class Process	Each of this type of process represents a single class of work item such as AQ notification, queue monitors, and cross process.	Database instances Advanced Queueing
RM	RAT Masking Slave Process	This background process is used with Data Masking and Real Application Testing.	Database instances
RMON	Rolling Migration Monitor Process	The RMON process is spawned on demand to run the protocol for transitioning an ASM cluster in and out of rolling migration mode.	Oracle ASM instance, Oracle RAC
RPOP	Instant Recovery Repopulation Daemon	The RPOP process is responsible for re-creating and repopulating data files from snapshots files. It works with the instant recovery feature to ensure immediate data file access. The local instance has immediate access to the remote snapshot file’s data, while repopulation of the recovered primary data files happens concurrently. Any changes in the data are managed between the instance’s DBW processes and RPOP to ensure the latest copy of the data is returned to the user.	Database instances
SAnn	SGA Allocator	A small fraction of SGA is allocated during instance startup. The SAnn process allocates the rest of SGA in small chunks. The process exits upon completion of SGA allocation.	Database instances
SCCn	ASM Disk Scrubbing Slave Check Process	SCCn acts as a slave process for SCRB and performs the checking operations. The possible processes are SCC0-SCC9.	Oracle ASM instances
SCRB	ASM Disk Scrubbing Master Process	SCRB runs in an Oracle ASM instance and coordinates Oracle ASM disk scrubbing operations.	Oracle ASM instances
SCRn	ASM Disk Scrubbing Slave Repair Process	SCRn acts as a slave process for SCRB and performs the repairing operations. The possible processes are SCR0-SCR9.	Oracle ASM instances
SCVn	ASM Disk Scrubbing Slave Verify Process	SCVn acts as a slave process for SCRB and performs the verifying operations. The possible processes are SCV0-SCV9.	Oracle ASM instances
TTnn	Redo Transport Slave Process	TTnn can run as multiple processes, where nn is 00 to ZZ.	Database instances, Data Guard

When the THREADED_EXECUTION initialization parameter is set to TRUE on Linux and UNIX, the DBW, PMON, PSP, and VKTM background processes run as operating system processes, and the other background processes run as operating system threads.

Reference:

http://docs.oracle.com/cd/E16655_01/server.121/e17615/bgprocesses.htm