×

System and method for stopping updates at a specified timestamp in a remote duplicate database facility

  • US 5,799,322 A
  • Filed: 01/30/1997
  • Issued: 08/25/1998
  • Est. Priority Date: 01/24/1995
  • Status: Expired due to Fees
First Claim
Patent Images

1. A distributed computer database system, comprising:

  • a local computer system having a local database stored on local memory media, application programs that modify the local database, and a transaction manager that stores audit records in a master audit trail (MAT) reflecting those application program modifications to the local database;

    the audit records in the MAT including A) commit/abort records each having transaction identifier, a transaction commit/abort status indicator, and a commit/abort timestamp indicating when a transaction associated with the transaction identifier committed or aborted, and B) database update records each having a transaction identifier and database modification information;

    a remote computer system, remotely located from the local computer system, the remote computer system having a backup database stored on memory media associated with the remote computer system;

    a communication channel for sending messages between the local computer system and the remote computer system;

    a remote data duplication facility (RDF), partially located on the local computer system and partially located on the remote computer system, for maintaining virtual synchronization of the backup database with the local database, the remote data duplication facility (RDF) including;

    an Extractor process executed by the local computer system that extracts audit records from the MAT, constructs a corresponding stream of image records by adding supplemental information to at least some of the audit records, the added information including an image record timestamp, and transmits the stream of image records to the remote computer system;

    the image records including commit/abort image records and database update image records;

    a Receiver process executed by the respective remote computer system that receives the image records transmitted by the Extractor process, and distributes the received image records to one or more image trails in the respective remote computer system; and

    one or more Updater processes executed by the respective remote computer system, wherein each Updater process reads the image records in an assigned one of the image trails and applies at least a subset of the read image records against the backup database by initiating redo operations of the database modifications denoted the subset of the read image records against the backup database;

    wherein each Updater process includes Stop Updaters at Timestamp instructions for preventing the Updater from applying against the backup database those of the read database update image records whose transaction ID matches the transaction ID in a corresponding commit/abort image record having a commit/abort timestamp whose value is not earlier than a specified Stop Timestamp.

View all claims
  • 4 Assignments
Timeline View
Assignment View
    ×
    ×