| 摘要 |
<p>Disclosed herein is a recovery method in a storage system that integrates shadow page and deferred update techniques. For update operations that occur during a transaction, update of a page in a buffer is not immediately reflected to a database, but is deferred until the transaction is committed. Instead, an updated buffer page is stored in a log volume in the unit of a page. When reading a page that does not exist in the buffer from the disk, the up-to-date page from the database or from the log volume is read. Here, a log table index is used to determine whether the up-to-date page exists in the database or in the log volume and to identify the position of the page stored in the log volume if the up-to-date page exists in the log volume. The invention has the following excellent advantages. It is simple and efficient because the deferred update file does not have to be additionally accessed for correct query processing. Besides, there is no performance degradation because the position of an updated page in the database is not changed, and thus, the original clustering of logically related data is preserved.</p> |
