Highly reliable online system

• US 5,307,481 A
• Filed: 02/25/1991
• Issued: 04/26/1994
• Est. Priority Date: 02/28/1990
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd., UFJ Bank Ltd. (Hong Kong) (Mitsubishi UFJ Financial Group Incorporated)
• Inventors: Tanaka, Shinji, Suzuki, Nobuyuki, Yamashita, Tetsuo, Nakagawa, Koichi, Ogawa, Kazuaki, Ogino, Kouji, Watanabe, Yoshikuni, Shimazaki, Hiroyuki, Yamasaki, Hajime, Shimizu, Takatoshi, Yano, Tatsushi, Mizoguchi, Masamichi, Kouguchi, Yukio, Fukagawa, Daisuke, Murabayashi, Satoshi
• Primary Examiner(s): Canney, Vincent P.
• Application Number:
  US07/660,633
• Time in Patent Office: 1,156 Days
• Field of Search: 371/9.1, 371/10.1, 371/11.2, 371/11.3, 371/8.1, 371/8.2, 395/575
• US Class Current: 714/11
• CPC Class Codes: G06F 11/1662 the resynchronized component or unit being a persistent storage device re-synchronization of failed mirror storage G06F11/2082; rebuild or reconstruction of parity RAID storage G06F11/1008
• CPC Class Codes: G06F 11/201 between storage system components
• CPC Class Codes: G06F 11/2033 switching over of hardware resources
• CPC Class Codes: G06F 11/2038 with a single idle spare processing component
• CPC Class Codes: G06F 11/2048 where the redundant components share neither address space nor persistent storage
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99955 Archiving or backup

Abstract

A highly reliable online system is disclosed which is provided with a backup computer center (sub-online system) in addition with an original computer center (main online system) in order to improve the reliability of the online system. With respect to the database, the main online system is provided with an original database (main database) while the sub-online system is provided with a backup database (sub-database) which is a duplicate of the main database. The main online system and the sub-online system are connected through a transmission path. Information on an update performed in the main database is transferred to the sub-online system through the transmission path to thereby update the sub-database in a manner similar to the main database. Terminal units are normally connected to the main online system, wherein the main database is updated by transactions inputted from the terminals. When a failure occurs in the main online system, the terminals are changed over to be connected to the sub-online system to allow transaction processing to be continued. Further, there are provided a control system for synchronizing contents between the main database and the sub-database when the original computer center is changed over to the backup computer center, a recovery system for recovering the main database or the sub-database from failures and an integration system for integrating both the main database and the sub-database when they are independently updated due to a failure in the transmission path or the like.

Claims

1. A database management method for integrating a sub-database into a main database after said main database and said sub-database, initially having had the same contents, were separately updated by different contents wherein said main database and said sub-database are connected with a main online system and a sub-online system, respectively, comprising the steps of:

providing each database record with a main database update sequence number and a sub-database update sequence number wherein each sequence number represents a number incremented each time the database record is updated;

transmitting database update information as well as both update sequence numbers from said sub-online system to said main online system wherein said update information and update sequence numbers are produced on the basis of the updated sub-database control;

comparing each update sequence number attached with the transmitted information to examine whether the main database record and a corresponding sub-database record have been both updated or only the corresponding sub-database record has been updated; and

,

updating the main database record by transmitted corresponding update information if only the corresponding sub-database records have been updated, while updating the main database record by reprocessing related input transactions keeping the update order of the database records if the main database record and the corresponding sub-database record have been both updated.