Patents by Inventor Ju Chang Lee

Ju Chang Lee has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7065537
    Abstract: An efficient logging method and system is disclosed that can be used to recover from a failure in a transaction system. It is based on a differential logging scheme that allows commutative and associative recovery operations. The method includes the steps of taking a before-image of the primary database in main memory before an update to the primary database; taking an after-image of the primary database after the update; generating a differential log by applying bit-wise exclusive-OR (XOR) between the before-image and the after-image; and performing either a redo or undo operation by applying XOR between said one or more logs and the before-image. Since XOR operations are commutative and associative, correct recovery is possible regardless of the creation sequence of log records. The present invention improves the performance of a logging system by reducing the size of log records and by allowing parallel execution of recovery operations.
    Type: Grant
    Filed: January 25, 2001
    Date of Patent: June 20, 2006
    Assignee: Transact In Memory, Inc.
    Inventors: Sang Kyun Cha, Ju Chang Lee, Ki Hong Kim
  • Publication number: 20020116404
    Abstract: An efficient logging method and system is disclosed that can be used to recover from a failure in a transaction system. It is based on a differential logging scheme that allows commutative and associative recovery operations. The method includes the steps of taking a before-image of the primary database in main memory before an update to the primary database; taking an after-image of the primary database after the update; generating a differential log by applying bit-wise exclusive-OR (XOR) between the before-image and the after-image; and performing either a redo or undo operation by applying XOR between said one or more logs and the before-image. Since XOR operations are commutative and associative, correct recovery is possible regardless of the creation sequence of log records. The present invention improves the performance of a logging system by reducing the size of log records and by allowing parallel execution of recovery operations.
    Type: Application
    Filed: January 25, 2001
    Publication date: August 22, 2002
    Applicant: Transact In Memory, Inc.
    Inventors: Sang Kyun Cha, Ju Chang Lee, Ki Hong Kim