A multiprocess Oracle database uses some additional processes called background processes. The background processes perform maintenance tasks required to operate the database and to maximize performance for multiple users.

  • Mandatory Background Processes
  • Optional Background Processes
  • Slave Processes

There are few processes which we can kill without terminating the instance.


  1. ARCn: Redo log archivers
  2. CJQn: Job scheduler coordinator
  3. Dnnn: Dispatchers
  4. DIA0: Diagnosability process 0
  5. DIAG: Diagnosability coordinator
  6. FDBA: Flashback data archiver process
  7. Jnnn: Job scheduler processes
  8. MMNL: Manageability Monitor Process 2
  9. MMON: Manageability Monitor Process
  10. PING: Interconnect latency measurement
  11. Qnnn: Queue cleanup processes
  12. QMNC: Queue coordinator
  13. RECO: Distributed recovery process
  14. Snnn: Shared servers
  15. SMCO: Space management coordinator
  16. Wnnn: Space management processes


  1. ACMS: Atomic controlfile to memory server
  2. CKPT: Checkpoint
  3. DBRM: Resource manager process
  4. DBWn: Database writer processes
  5. LGWR: Redo log writer
  6. LMDn: Global enqueue service daemons
  7. LMON: Global enqueue service monitor
  8. MMAN: Memory manager
  9. PMON: Process monitor
  10. PSPn: Process spawners
  11. RMSnRAC management server
  12. RVWR: Recovery writer
  13. SMON: System monitor process
  14. VKTM: Virtual keeper of time process

Note: Above processes were tested on Oracle 11g. “n” respresents the number


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