Highly reliable online system

• US 5,596,706 A
• Filed: 08/10/1994
• Issued: 01/21/1997
• Est. Priority Date: 02/28/1990
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd., UFJ Bank Ltd. (Hong Kong) (Mitsubishi UFJ Financial Group Incorporated)
• Original Assignee: Hitachi, Ltd., UFJ Bank Ltd. (Hong Kong) (Mitsubishi UFJ Financial Group Incorporated)
• Inventors: Yamashita, Tetsuo, Nakagawa, Koichi, Ogawa, Kazuaki, Ogino, Kouji, Shimazaki, Hiroyuki, Yamasaki, Hajime, Shimizu, Takatoshi, Yano, Tatsushi, Mizoguchi, Masamichi, Kouguchi, Yukio, Fukagawa, Daisuke, Murabayashi, Satoshi, Tanaka, Shinji, Suzuki, Nobuyuki, Watanabe, Yoshikuni
• Primary Examiner(s): Canney, Vincent P.
• Application Number:
  US08/288,584
• Time in Patent Office: 895 Days
• Field of Search: 395/575, 395/600, 395/625, 395/9.1
• US Class Current: 714/6.3
• 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 synchronization control system comprising:

a main computer system for accessing ones of a plurality of related first records in a main database based on transactions inputted from terminals wherein said accessing includes updating said ones of a plurality of related first records, and delivering main database update information relating to the updating performed on said main database; and

,

a sub-computer system coupled with said main computer system for receiving the update information and updating ones of a plurality of related second records in a sub-database corresponding to said main database, the updating being executed on the basis of said update information, wherein;

said terminals include means for storing and transmitting both i) transaction sequence numbers counted up each time a transaction is generated and ii) transaction data to said main computer system;

said main computer system includes means for transmitting the main database update information and the transaction sequence number of each of said terminals to said sub-computer system; and

,

means in each of said-terminals operative when said main computer system is changed over to said sub-computer system, for receiving a latest transaction sequence number of a transaction which has been reflected to the sub-database from said sub-computer system, comparing the received transaction sequence number with the latest transaction sequence number transmitted to said main computer system and stored therein and automatically retransmitting a number of transactions, said number matching the difference between the received transaction sequence number and the latest transaction sequence number stored in the terminal, whereby contents of said main database and said sub-database are synchronized with each other.

2. A database synchronization control system according to claim 1 further comprising means for connecting said sub-computer system to said terminals in place of said main computer system when said main computer system is inoperative.

3. A database synchronization control system according to claim 1 further comprising a transmission path coupling said sub-computer system with said main computer system for transmitting said main database update information and said transaction sequence number.

4. A database synchronization control system comprising an original computer center connected by a multiplexed circuit to a backup computer center and a terminal adapted for selective connection to said original computer center and said backup computer center, wherein:

said original computer center includes;

an original database;

means for processing a transaction received from said terminal to update a record forming a first updated record in said original database;

means for transmitting said first updated record via said multiplexed circuit; and

,

said backup computer center includes;

a backup database;

means for storing said first updated record transmitted from said original computer center via said circuit into said backup database, and processing said transaction received into said original computer center from said terminal to update a record in said backup database when the terminal is connected to said backup computer center.

5. A database synchronization control system according to claim 4, wherein said means for transmitting is adapted to transmit a plurality of said first updated records in random order using said multiplexed circuit.

6. A database synchronization control system according to claim 5, wherein said means for storing and processing includes means for sorting said first updated records transmitted in random order to update records of said backup database in an order of updates performed in said original computer center.

7. A database synchronization control system according to claim 6, wherein said transmitting means includes means for transmitting said updated record associating information for identifying said transaction with said updated record.

8. A database synchronization control system according to claim 7, wherein said information for identifying said transaction includes a terminal number and a transaction sequence number.

9. A database synchronization control system comprising:

a main computer center including a main database and a backup database;

means for reflecting contents of said main database into said backup database using on-line communication;

a backup computer center including a sub database;

a plurality of terminals adapted for selective connection to said backup computer center;

means for grouping, upon a failure of said means for reflecting, said plurality of terminals into a first group of terminals adapted for connection to said main computer center, and a second group of terminals adapted for connection to said backup computer center independently; and

,

means for integrating said main database and said sub database by reflecting update information of said sub database obtained by updating by said second group of terminals and update information of said main database obtained by updating by said first group of terminals, respectively, to said main database on a basis of the contents of said sub database, and to said sub database on a basis of the contents of said main database, for restoration of said main database and said sub database in response to said failure.

10. A database synchronization control system in which a original computer center and a backup computer center are connected through a multiplexed circuit, wherein said original computer center comprises:

an original database;

means for processing transaction input from a terminal, and transmitting the result of said processing to said terminal;

means for determining whether a record of said original database has been updated by said transaction processing, and when said record has been updated, for updating contents of said original database and randomly transmitting, through said multiplexed circuit, plurality of said updated records associating said respective records information for identifying the order of corresponding transaction processings.