| 摘要 |
A method and apparatus for recovering an object that includes logged data and a set of non-logged data is provided. According to the method, a copy of the object resides in volatile memory. A change is made to the copy of the object. If the change does not change any data within the object other than the non-logged data, then the change is made to the copy of the object without generating redo information. If the change changes any data within the object other than the non-logged data, then redo information is generated in response to the change. The redo information is stored on non-volatile storage. After a failure, the redo information is used to restore all data within the object other than the non-logged data. The non-logged data may be restored by retrieving the non-logged data from a different object for which redo information was generated for the non-logged data. A description of how this technique may be used to efficiently perform selective non-deferred block cleanout is also provided. |
