Database Processes

• PMON - Process Monitor - free up resource on user process failure - runs on 3 seconds intervel - oradebug setmypid;oradebug wakeup 2
• SMON - System Monitor - performs instance recovery, cleans up after dirty shutdowns and coalesces adjacent free extents into larger free extents - 5 minutes intervel
• ARCn - Redo Log Archiver - starts with ARCHIVE LOG MODE enabled - archive on-line redo log files to an archive destination
• LGWR - Redo Log Writer - writes the redo log buffers to the on-line redo log files - on mirrored, writes simultaneously on members of the group
• DBWn - Database Writer - writes data from the SGA to datafile - on SGA data buffer cache fills, it selects buffer using LRU algo to write in disk
• CKPT - Checkpoint process - timestamps datafile and control file - v$sysstat, count of checkpoint completed
• RECO - Recoverer - starts with DISTRIBUTED_TRANSACTIONS enabled - resolves in-doubt transactions across distributed databases
• CJQn - Job Queue Coordinator - Job scheduler - A main program (the coordinator) and slave programs for execution - job_queue_processes parameter
• QMNn - Queue-monitor processes - Manages Oracle Streams Advanced Queuing
• Dnnn - Dispatcher Processes (multiplex server-processes on behalf of users)
• Snnn - Shared server processes (serve client-requests)
• MMAN - Memory Manager - manages the dynamic resizing of SGA memory areas - use sga_target,memory_target parameters
• LSP0 - Logical standby coordinator process (controls Data Guard log-application)
• MRP - Media-recovery process (detached recovery-server process)
• MMON - Gathers memory statistics or snapshots and stores information in AWR - issue alerts when metrics exceeds thresholds
• MMNL - Memory monitor light - Assists MMON process - Flush ASH buffer to AWR tables
• PSP0 - Process-spawner (spawns Oracle processes)
• RFS - Remote file server process (archive to a remote site)
• DBRM - DB resource manager (new in 11g)
• DIAGn - Diagnosability process (new in 11g)
• FBDA - Flashback data archiver process (new in 11g)
• VKTM - Virtual Timekeeper (new in 11g)
• Wnnn - Space Management Co-ordination process (new in 11g)
• SMCn - Space Manager process (new in 11g)