Replicating a database by the sequential application of hierarchically sorted log records
June 25, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesDisc memory apparatus System for merging virtual partitions of a distributed database Method for restoring a database after I/O error employing write-ahead logging protocols Soft checkpointing system using log sequence numbers derived from stored data pages and log records for database recovery Data availability in restartable data base system Concurrently applying redo records to backup database in a log sequence using single queue server per queue at a time Method and apparatus for aligning a restored parent environment to its child environments with minimal data loss Method for managing database recovery from failure of a shared store in a system including a plurality of transaction-based systems of the write-ahead logging type Recovery logging in the presence of snapshot files by ordering of buffer pool flushing Patent #: 5369757 InventorsApplicationNo. 959849 filed on 10/13/1992US Classes:707/201, Coherency (e.g., same view to multiple users)707/204, Archiving or backup714/7, Reconfiguration (e.g., adding a replacement storage component)714/16Forward recovery (e.g., redoing committed action)ExaminersPrimary: Kulik, Paul V.Assistant: Lintz, Paul R. Attorney, Agent or FirmInternational ClassG06F 017/30AbstractA method and system are provided for continuously maintaining replicas of an active database in a backup system for disaster recovery purposes. Redo records transmitted from an active system are received into a dataspace work area in a backup system memory. Redo records in the work area for an uncommitted database transaction are grouped together. When a transaction becomes a committed transaction, the redo records for the transaction are sorted with redo records from other committed transactions according to database, block number within a database, offset location within a block, and sequence of occurrence. A plurality of update blocks from a backup database are read into a buffer in the backup system memory. The sorted redo records are sequentially applied to corresponding data records in the update blocks. The update blocks are then immediately written back to the database.Other References
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