Buffer Lock Mode and Compatibilities

Buffer Modes:

  • KCBMNEW : New buffer for exclusive access
  • KCBMSHR : Current buffer for shared access
  • KCBMEXL : Current buffer for exclusive access
  • KCBMCR : CR buffer for shared access
  • KCBMCRX : Variant of CR mode
  • KCBMNULL : Used to keep a reference to the buffer

oracle_buffer_lock_compatibilities

Buffer State

  • KCBBHFREE : buffer free
  • KCBBHEXLCUR : buffer current
  • KCBBHSHRCUR : buffer current
  • KCBBHCR : buffer consistent read
  • KCBBHREADING : being read
  • KCBBHMRECOVERY : media recovery
  • KCBBHIRECOVERY : crash or instance recovery
  • KCBBHWRITING : write clone
  • KCBBHPI : past image
  • KCBBHMEMORY : allocated memory buffer
  • KCBBHMWRITING : media recovery write clone
  • KCBBHDONATED : donated to another memory component

Buffer Class

  • KCBCDATA : DB blocks
  • KCBCSORT : sort blocks
  • KCBCSVUN : save undo blocks
  • KCBCSEGH : segment header blocks
  • KCBCSVSH : save undo segment hdrs
  • KCBCFRLS : free list blocks
  • KCBCEMAP : extent map
  • KCBCBMAP : bitmap block
  • KCBCIMAP : bitmap index block
  • KCBCBFSB : bitmapped file space bitmap
  • KCBCBFSH : bitmapped file space header
  • KCBCPW : prewarmed buffers class initially

 

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