Patent ID: 8818943
Filing Date: 2014-08-26
Classification: G06F

Abstract:
1. A method of mirror resynchronization of fixed length pages in a mirrored pair of databases comprising a primary database and a mirror database supporting transactions, the method comprising: writing, for each page change of a plurality of page changes to the fixed length pages, a record of the page change to a transaction log buffer until reaching a first checkpoint of a plurality of checkpoints, the checkpoints occurring at periodic intervals, wherein each record includes a log sequence number (LSN); upon reaching the first checkpoint, writing the records in the transaction log buffer to a primary transaction log file for the primary database and a mirror transaction log file for the mirror database; capturing in a change tracking log, upon loss of synchronization and after reaching the first checkpoint, write-related page changes written to the transaction log buffer with a LSN greater than the LSN of the first checkpoint; stopping, upon starting mirror resynchronization, the capturing of page changes in the change tracking log while continuing to record page changes due to ongoing transactions in the transaction log; determining, for each page referenced by a page change in the change tracking log, the most recent transaction for that page captured in the change tracking log; and updating the mirror database using the most recent transactions in the change tracking log for each page referenced by a page change in the change tracking log.