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  • backgroup process

     

    DBWn writes when

    1.      Checkpoint

    2.      Dirty buffers threshold reached

    3.      No free buffers

    4.      Timeout

    5.      RAC ping request

    6.      Tablespace offline

    7.      Tablespace read only

    8.      Table DROP or TRUNCATE

    9.      Tablespace BEGIN BACKUP

    GLWR writes when

    1.      At commit

    2.      When one-third full

    3.      When there is 1MB of redo

    4.      Every 3 seconds

    5.      Before DBWn writes

    SMON Responsibilites

    1.      instance recovery:A.Rolls forward changes in the redo logs;B.Opens the database or user access;C.Rolls back uncommitted transactions

    2.      Coalesces free space ever 3 sec

    3.      Deallocates temporary segments

    PMON

    Cleans up after failed processes by

    A.     Rolling back the transaction

    B.     Releasing locks

    C.     Releasing other resources

    D.     Restarts dead dispatchers

    CKPT

    1.      signalling DBWn at checkpoints

    2.      Updating datafile headers and control files with checkpoint information

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  • 原文地址:https://www.cnblogs.com/jimeper/p/1261250.html
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