Method and System for High-Availability Database

Abstract

The present invention provides a system switching function for database management systems which requires no standby resources idling during normal operation. One aspect of the invention is directed to a method for processing databases in a system which includes a plurality of storage areas each storing a database and a plurality of computers each having a database management program running thereon which manages one of the plurality of storage areas. Each storage area is associated with only the computer managing the storage area. The method comprises, when a failure has occurred in one of the plurality of computers as a failed computer, obtaining preset substitution information indicating that the storage area managed by the database management program running on the failed computer is to be managed by the database management program running on another one of the plurality of computers as a substitute computer; and, based on the substitution information, changing association of the storage area with the failed computer to the substitute computer. The storage area is to be managed by the database management program running on the substitute computer.

1 - 3 . (canceled) 
   
   
       4 . A method for processing databases in a system comprising a processing request server, a plurality of storage areas, and a plurality of database access servers, wherein each storage area in the plurality of storage areas includes at least one database, wherein each database access server in the plurality of database access servers is associated with a storage area from among the plurality of storage areas thereby enabling said each database access server to manage and access its associated storage area, the method comprising:
 when a failure has occurred in a first database access server from among the plurality of database access servers, then obtaining preconfigured substitution information including a mapping between the first database access server and a second database server from among the plurality of database access servers, wherein the first database access server is different from the second database server;   based on the mapping, re-associating a first storage area associated with the first database access server such that the first storage area becomes associated the second database access server thereby enabling the second database access server to manage and access the first storage area;   receiving at the processing request server a processing request directed to the first database access server;   determining if the first database access server is in operation;   if the first database access server is in operation, then forwarding the processing request to the first database access server, wherein the first database access server is configured to process the forwarded processing request;   if the first database access server is not in operation, then:   identifying the second database access server as a substitute for the first database access server based on the preconfigured substitution information; and   transmitting another processing request to the second database access server, wherein the second database access server is configured to receive said another processing request, obtain execution environment information for the first database access server, switch an execution environment of the second database access server to that of the first database access server based on the execution environment information, process said another processing request on behalf of the first database access server, and return to an original execution environment of the second database access server after completion of processing said another processing request.   
   
   
       5 . The method of  claim 4 , wherein the mapping associates an identifier of the first database access server with an identifier of the second database access server, the mapping indicating that the storage area associated with the first database access server is to be associated with the second database access server when a failure occurs in the first database access server. 
   
   
       6 . The method of  claim 5 , wherein the mapping further indicates that a storage area associated with second database access server is to be associated with the first database access server when a failure occurs in the second database access server. 
   
   
       7 . The method as recited in  claim 4 , wherein the preconfigured substitution information comprises a substitution configuration in which a group of database access servers from the first database access server to a last database access server are associated with each other such that the first database access server is to manage a storage area for the second database access server, the second database access server is to manage a storage area for a third database access server, and the last database access server is to manage a storage area for the first database access server. 
   
   
       8 . The method as recited in  claim 4 , wherein the preconfigured substitution information comprises an n-to-1 substitution configuration whereby one database access server is to manage storage areas for n other database access servers. 
   
   
       9 . A system for processing databases, the system comprising:
 a processing request receiving server;   a plurality of storage areas, each storage area including at least one database; and   a plurality of database access servers, each database access server being associated with a storage area in the plurality of storage areas, thereby enabling said each database access server to manage and access its associated storage area,   wherein the processing request receiving server is configured to:
 receive a processing request directed to a first database access server in the plurality of database access servers; 
 determine whether the first database access server is in operation; 
 forward the processing request to the first database access server, wherein the first database access server is configured to process the forwarded processing request when the first database access server is in operation; and 
 when the first database access server is not in operation:
 obtain preconfigured substitution information including a mapping between the first database access server and a second database access server in the plurality of database access servers; 
 identify the second database access server as a substitute for the first database access server based on the preconfigured substitution information; 
 transmit another processing request to the second database access server, wherein the second database access server is configured to receive said another processing request, obtain execution environment information for the first database access server, switch an execution environment of the second database access server to that of the first database access server based on the execution environment information, process said another processing request on behalf of the first database access server, and return to an original execution environment of the second database access server after completion of processing said another processing request. 
 
   
   
   
       10 . The system as recited in  claim 9 , wherein the preconfigured substitution information comprises a substitution configuration in which a group of database access servers from the first database access server to a last database access server are associated with each other such that the first database access server is to manage a storage area for the second database access server, the second database access server is to manage a storage area for a third database access server, and the last database access server is to manage a storage area for the first database access server. 
   
   
       11 . The system as recited in  claim 9 , wherein the preconfigured substitution information comprises an n-to-1 substitution configuration whereby one database access server is to manage storage areas for n other database access servers. 
   
   
       12 . The system of  claim 9 , wherein the mapping associates an identifier of the first database access server with an identifier of the second database access server, the mapping indicating that a storage area associated with the first database access server is to be associated with the second database access server when a failure occurs in the first database access server. 
   
   
       13 . The system of  claim 9 , wherein the preconfigured substitution information includes a plurality of mappings between database access servers, each mapping including priority information indicating a priority of said each mapping with respect to other mappings.