Friday, October 4, 2013

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.


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