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US Patent 5530855 - Replicating a database by the sequential application of hierarchically sorted log records
US Patent Issued on June 25, 1996
Estimated Patent Expiration Date:
June 25, 2013Estimated 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.
Estimated Patent Expiration Date:
June 25, 2013Estimated 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.AbstractA 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
| 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 FirmUS Patent References4357635, Disc memory apparatusIssued on: 11/02/1982 Inventor: Hasegawa4853843, System for merging virtual partitions of a distributed database Issued on: 08/01/1989 Inventor: Ecklund4945474, Method for restoring a database after I/O error employing write-ahead logging protocols Issued on: 07/31/1990 Inventor: Elliott, et al.5043866, Soft checkpointing system using log sequence numbers derived from stored data pages and log records for database recovery Issued on: 08/27/1991 Inventor: Myre, Jr., et al.5155678, Data availability in restartable data base system Issued on: 10/13/1992 Inventor: Fukumoto, et al.5170480, Concurrently applying redo records to backup database in a log sequence using single queue server per queue at a time Issued on: 12/08/1992 Inventor: Mohan, et al.5274803, Method and apparatus for aligning a restored parent environment to its child environments with minimal data loss Issued on: 12/28/1993 Inventor: Dubin, et al.5280611, 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 Issued on: 01/18/1994 Inventor: Mohan, et al.5369757Recovery logging in the presence of snapshot files by ordering of buffer pool flushing Issued on: 11/29/1994 Inventor: Spiro, et al. International ClassG06F 017/30 |
