INFORMATION PROCESSING SYSTEM, DATA UPDATE METHOD AND DATA UPDATE PROGRAM

• US 20100076939A1
• Filed: 08/17/2009
• Published: 03/25/2010
• Est. Priority Date: 09/05/2008
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: KAWAMOTO, Shinichi, SUGAYA, Natsuko, IWAKI, Masashi, YAKO, Katsushi, SUGIMOTO, Yuki, ANZAI, Takeshi
• Granted Patent: US 8,645,319 B2
• Time in Patent Office: Days
• US Class Current: 707/690
• CPC Class Codes: G06F 16/2358 Change logging, detection, and notification replication G06F16/27

Abstract

An information processing system, a data update method and a data update program are disclosed. In a data base system of master-slave configuration, the update result can be accessed also on slave side with the access request immediately after the particular update. The data base system DBS includes a master DB computer and at least a slave DB computer. The slave DB computer judges from the count on an update counter table whether the update log received from the master DB computer is to be reflected in a duplicate data base or not. Thus, the lost update problem is solved while at the same time realizing a high-speed process.

Claims

1. An information processing system comprising:

a first information processing unit for managing an original data base constituting a mass of data; and

at least one second information processing unit for managing a duplicate data base constituting a duplicate of the original data base;

wherein an update log storing the update information generated in the original data base of the first information processing unit is transmitted to the second information processing unit and reflected in the duplicate data base;

wherein the second information processing unit includes;

a request processing unit which, upon acceptance of an update request from an external computer, transmits the update request to the first information processing unit to update the original data base while at the same time updating the duplicate data base of the second information processing unit;

an update information management unit for checking, for each data in the duplicate data base, whether the update log corresponding to the update request accepted is received from the first information processing unit or not; and

an update reflection judgment unit which, upon acceptance of a new update log from the first information processing unit, judges whether the update log is to be reflected in the duplicate data base or not, based on the information stored in the update log and the information managed by the update information management unit, and upon judgment that the update log is to be so reflected, reflects the update content of the update log in the duplicate data base.

2. The information processing system according to claim 1,

wherein the first Information processing unit is a first data base computer and the second information processing unit is a second data base computer.

3. The information processing system according to claim 2,

wherein the update information management unit includes:

an update counter table for holding a counter corresponding to each data in the duplicate data base;

an update counter increment unit for incrementing, by a predetermined number, the count on the counter corresponding to the data to be updated in the update counter table, at the time of updating the duplicate data base when processing the update request in the second data base computer; and

an update counter decrement unit which, upon reception from the first data base computer the update log corresponding to the update request received from an external computer by the second data base computer, decrements, by a predetermined number, the count on the counter corresponding to the data to be updated in the update counter table;

wherein the update reflection judgment unit, upon reception of a new update log from the first data base computer, accesses the update counter table and in the case where the count on the counter corresponding to the data to be updated is not larger than a predetermined value, reflects the update content of the update log in the duplicate data base of the second data base computer.

4. The information processing system according to claim 2,

wherein a counter corresponding to each data is held in the duplicate data base of the second data base computer in addition to the duplicate of the original data base;

wherein the update information management unit includes;

an update counter increment unit for incrementing, by a predetermined number, the count on the counter corresponding to the data to be updated in the duplicate data base, at the time of updating the duplicate data base when processing the update request in the second data base computer; and

an update counter decrement unit which, upon reception from the first data base computer an update log corresponding to the update request received from an external computer by the second data base computer, decrements, by a predetermined number, the count on the counter corresponding to the data to be updated in the duplicate data base; and

wherein the update reflection judgment unit, upon acceptance of a new update log from the first data base computer, accesses the update counter table, and in the case where the count on the counter corresponding to the data to be updated is not larger than a predetermined value, reflects the update content of the update log in the duplicate data base of the second data base computer.

5. The information processing system according to claim 2,

wherein the second data base computer manages the version of the update of the data stored in the duplicate data base, and the update log-reflected pointer indicating the version that has reflected the update log is held in the duplicate data base for the data managed by version;

wherein the request processing unit, at the time of updating the duplicate data base, duplicates the data to be updated and generates the data of the next version by updating the value of the data;

wherein the update information management unit, upon reception from the first data base computer an update log corresponding to the update request received from an external computer by the second data base computer, changes, to the next version, the update log-reflected pointer corresponding to the data to be updated in the duplicate data base; and

wherein the update reflection judgment unit, upon acceptance of a new update log from the first data base computer, accesses the duplicate data base and, in the case where the update log-reflected pointer corresponding to the data to be updated is the latest version, reflects the update content of the update log in the duplicate data base of the second, data base computer.

6. The information processing system according to claim 2,

wherein a server information table for storing the information on the second data base computer is held in the original data base of the first data base computer;

and

wherein the second data base computer includes;

a server information provision unit for transmitting, to the first data base computer, an update request for updating the data storing the second data, base computer of the server information table, and

a server information judgment unit for acquiring the information on the second data base computer from the update log data to update the server information table in the update log received from the first data base computer, and judging whether the particular update log corresponds to the update request received by the second data base computer or not.

7. A data update method for an information processing system comprising a data base computer for managing an original data base constituting a mass of data and at least one client computer having a data cache for holding a duplicate data base as a copy of the original data base in a main storage unit;

wherein an update log storing the update information generated in the original data base of the data base computer is transmitted to the data cache of the client computer and reflected in the duplicate data base;

wherein the data cache includes a request processing unit, an update information management unit and an update reflection judgment unit;

wherein the request processing unit, upon acceptance of a data update request, transmits the update request to the data base computer to update the original data base while at the same time updating the duplicate data base;

wherein the update information management unit checks, for each data in the duplicate data base, whether the update log corresponding to the update request is received from the data base computer or not; and

wherein the update reflection judgment unit, upon acceptance of a new update log from the data base computer, judges whether the update log is to be reflected in the duplicate data base, based on the information stored in the update log and the information managed by the update information management unit, and upon judgment that the update log is to be so reflected, reflects the update content of the update log in the duplicate data base.

8. The data update method according to claim 7,

wherein the update information management unit includes an update counter table for holding the counter corresponding to each of the data in the duplicate data base, an update counter increment unit and an update counter decrement unit;

wherein the update counter increment unit, at the time of updating the duplicate data base when processing the update request, increments, by a predetermined number, the count on the counter corresponding to the data to be updated in the update counter table;

wherein the update counter decrement unit, upon reception of the update log corresponding to the update request from the data base computer, decrements, by a predetermined number, the count on the counter corresponding to the data to be updated in the update counter table; and

wherein the update reflection judgment unit, upon acceptance of a new update log from the data base computer, accesses the update counter table, and in the case where the count on the counter corresponding to the data to be updated is not larger than a predetermined value, reflects the update content of the update log in the duplicate data base.

9. The data update method, according to claim 7,

wherein a counter corresponding to each data is held in the duplicate data base of the data cache in addition to the duplicate of the original data base;

wherein the update information management unit includes an update counter increment unit and an update counter decrement unit;

wherein the update counter increment unit, at the time of updating the duplicate data base when processing the update request, increments, by a predetermined number, the count on the counter corresponding to the data to be updated in the duplicate data base;

wherein the update counter decrement unit, upon reception of an update log corresponding to the update request from the data base computer, decrements, by a predetermined number, the count on the counter corresponding to the data to be updated in the duplicate data base; and

wherein the update reflection judgment unit, upon acceptance of a new update log from the data base computer, accesses the update counter table, and in the case where the count on the counter corresponding to the data to be updated is not larger than a predetermined value, reflects the update content of the update log in the duplicate data base.

10. The data update method according to claim 7,

wherein the update of the data stored in the duplicate data base is managed by version;

wherein the update log-reflected pointer indicating the version with the update log reflected for the data managed by version is held in the duplicate data base;

wherein the request processing unit, at the time of updating the duplicate data base, duplicates the data to be updated, and by updating the value of the data, generates the data of the next version;

wherein the update information management unit, upon reception of an update log corresponding to the update request from the data base computer, changes to the next version the update log-reflected pointer corresponding to the data to be updated in the duplicate data base; and

wherein the update reflection judgment unit, upon acceptance of a new update log from the data base computer, accesses the duplicate data base, and in the case where the update log-reflected pointer corresponding to the data to be updated is the latest version, reflects the update content of the update log in the duplicate data base.

11. The data update method according to claim 7,

wherein a server information table storing the information on a data cache is held in the original data base;

wherein the data cache includes a server information provision unit and a server information judgment unit;

wherein the server information provision unit transmits an update request to the data base computer to update the data storing the data cache in the server information table; and

wherein the server information judgment unit acquires the information on the data cache from the update log data for updating the server information table in the update log received from the data base computer, and judges whether the update log corresponds to the update request received by the data cache.

12. A data update program for causing a computer to carry out the data update method described in claim 11.