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