Method and system for highly-parallel logging and recovery operation in main ...

(54) METHOD AND SYSTEM FOR

HIGHLY-PARALLEL LOGGING AND
RECOVERY OPERATION IN
MAIN-MEMORY TRANSACTION
PROCESSING SYSTEMS

(75) Inventors: Sang Kyun Cha, Seoul (KR); Ju
Chang Lee, Kyonggi-do (KR); Ki
Hong Kim, Seoul (KR)

Correspondence Address:
FLESHNER & KIM
P.O. Box 221200
Chantilly, VA 20153-1200 (US)

(73) Assignee: Transact In Memory, Inc.

(21) Appl. No.: 09/768,301

(22) Filed: Jan. 25, 2001

(30) Foreign Application Priority Data

Jun. 7, 2000 (KR) 2000/31166

Publication Classification

(51) Int. CI.7 G06F 17 30

(52) U.S. CI 707/202; 707/204

(57) ABSTRACT

An efficient logging method and system is disclosed that can be used to recover from a lailure 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.