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





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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