| 主权项 |
1. A computer-implemented method for rewinding a virtual database system, the method comprising:
storing, in a database storage system, a plurality of snapshots of a source database, a snapshot representing a point-in-time copy of database blocks of the source database, wherein one or more database blocks are shared across snapshots of the source database; provisioning a virtual database based on database blocks of a snapshot of the source database; maintaining, by the database storage system, one or more timeflows for the virtual database, each timeflow representing changes to the virtual database starting from an initial state of the virtual database, the representation of changes comprising snapshots of the virtual database taken at different points in time, wherein one or more database blocks are shared across a plurality of snapshots of the virtual database; receiving a request to rewind the virtual database to a previous state of the virtual database, the request identifying a timeflow of the virtual database and a target point in time associated with the identified timeflow, rewinding the virtual database by modifying the virtual database to refer to database blocks of a snapshot of the virtual database associated with the timeflow, the snapshot of the virtual database saved before or at the target point in time; and maintaining a new timeflow for the rewound virtual database, the new timeflow comprising representations of changes caused by subsequent updates to the rewound virtual database. |
