background processes

Here’s a list of background processes:

The System Monitor carries out a crash recovery when a crashed insance is started up again. It also cleans temporary segments.
The Process Monitor checks if a user process fails and if so, does all cleaning up of resources that the user process has aquired.
The Database Writer writes dirty blocks from the database buffer to the datafiles. How many DBWn Processes are started is determined by the initialization parameter DB_WRITER_PROCESSES. DBWR also writes the actual SCN with the Block.
The Log Writer writes the redo log buffer from the SGA to the online redo log file.
The memory manager
Managed recovery process: the process that applies archived redo log to the standby database.
The remote file server process on the standby database receives archived redo logs from the primary database.
The Distributed Transaction Recovery Process finds pending (distributed) transaction and resolves them.
The Checkpoint Process reqularly initiates a checkpoint which uses DBWR to write all dirty blocks back to the datafiles, thus synchronizing the database. Since a Checkpoint records the current SCN, in a recovery only redo records with a SCN higher than that of the last checkpoint need to be applied.
The Archiver Process archives redo log files if ARCHIVELOG is enabled.
* Dnnn
The Dispatcher Process is used in a shared server environment.
* Snnn
The Shared Server Process is used in a shared server environment.
The lock manager.
* LMD0
* QMNn
AQ Time Manager
Trace writer
The wakeup monitor process.
* LCKnnn
Inter-instance locking process.
* SNPnnn
The snapshot process.
New background process in Oracle 10g.
The Data Guard Broker process.
The snapshot process.

Background processes have v$session.type = ‘BACKGROUND’


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