Duplicating database contents

Abstract

The invention provides data processing, data control and information methods and systems for efficiently duplicating contents of a database in the data control system. An example of a data processing system includes: a cache unit acquiring, from a data control system which categorizes a plurality of data elements into a plurality of clusters and stores the plurality of clusters; a group-of-clusters update information acquisition unit for acquiring from the data control system group-of-clusters update information with respect to a group of clusters consisting of two or more clusters; a group-of-clusters update information computation unit for computing group-of-clusters update information with respect to the group of clusters based on two or more pieces of cluster update information; and an update judging unit for judging that a cached data element belonging to the group of clusters is the most updated one.

1 . A data processing system for acquiring a data element from a data control system and performing data processing on the data element, the data control system categorizing a plurality of data elements into a plurality of clusters and storing the plurality of clusters, comprising: 
 a cache unit for acquiring from the data control system a data element belonging to a single cluster of the plurality of clusters, and cluster update information of which a data value is changed when any data element belonging to the single cluster is updated, and for caching the data element and the cluster update information thus acquired;    a group-of-clusters update information acquisition unit for acquiring, from the data control system, group-of-clusters update information which is computed by the data control system based on two or more pieces of the cluster update information stored in the data control system with respect to two or more of the clusters containing two or more of the data elements having been cached, the group-of-clusters update information pertaining to a group of clusters consisting of the two or more clusters;    a group-of-clusters update information computation unit for computing the group-of-clusters update information with respect to the group of clusters based on the two or more pieces of cluster update information having been cached; and    an update judging unit for judging that an aforementioned data element thus cached belonging to an aforementioned cluster of the group of clusters is the most updated one in a condition where the group-of-clusters update information which is computed by the group-of-clusters update information computation unit coincides with the group-of-clusters update information which is acquired from the data control system.    
   
   
       2 . A data processing system according to  claim 1 , wherein, in a condition where first group-of-clusters update information computed by the group-of-clusters update information computation unit with respect to a first group of clusters of the aforementioned groups of clusters consisting of a first number of the clusters does not coincide with first group-of-clusters update information acquired from the data control system with respect to the first group of clusters: 
 the group-of-clusters update information acquisition unit acquires, from the data control system, with respect to a second group of clusters belonging to the first group of clusters and consisting of a second number of the clusters, second group-of-clusters update information based on cluster update information for the second number of the clusters belonging to the second group of clusters, the second number being smaller than that of the first group-of-clusters,    the group-of-clusters update information computation unit computes the second group-of-clusters update information for the second group-of-clusters, based on the second number of the cached cluster update information, and    the update judgment unit, in a condition where the second group-of-clusters update information computed by the group-of-clusters update information computation unit coincides with the second group-of-clusters update information acquired from the data control system, judges that the cached data elements belonging to the clusters in the second group of clusters are the most updated.    
   
   
       3 . A data processing system according to  claim 2 , wherein, in a condition where the second group-of-clusters update information computed by the group-of-clusters update information computation unit does not coincide with the second group-of-clusters update information acquired by the data control system, 
 the group-of-clusters update information acquisition unit acquires, from the data control system, with respect to a third group of the clusters belonging to the second group of the clusters and consisting of a third number of the clusters, third group-of-clusters update information based on the cluster update information for the third number of the clusters belonging to the third group of clusters, the third number being smaller than that of the second group of clusters,    the group-of-clusters update information computation unit computes the third group-of-clusters update information for the third group of the clusters, based on the third number of the cached cluster update information, and    the update judgment unit, in a condition where the third group-of-clusters update information computed by the group-of-clusters update information computation unit coincides with the third group-of-clusters update information acquired from the data control system, judges that the cached data elements belonging to the clusters in the third group of clusters are the most updated.    
   
   
       4 . A data processing system according to  claim 2 , wherein 
 the group-of-clusters update information acquisition unit acquires, from the data control system, with respect to a fourth group of clusters consisting of a fourth number of the clusters belonging to the first group of clusters and not belonging to the second group of clusters, fourth group-of-clusters update information based on the cluster update information for the fourth number of the clusters belonging to the fourth group of clusters,    the group-of-clusters update information computation unit computes the fourth group-of-clusters update information with respect to the fourth group of clusters, based on the fourth number of the cached cluster update information, and    the update judgment unit, in a condition where the fourth group-of-clusters update information computed by the group-of-clusters update information computation unit accords with the fourth group-of-clusters update information acquired by the data control system, judges that the cached data elements belonging to the clusters within the fourth group-of-clusters are the most updated.    
   
   
       5 . A data processing system according to  claim 4 , wherein 
 the cache unit caches, with respect to a fifth group of clusters which consists of all of the clusters belonging to the first group of clusters and belonging to neither of the second group of clusters nor the fourth group of clusters and which does not include any of the cached data elements belonging to any of the clusters therein, fifth group-of-clusters update information based on the cluster update information for all of the clusters belonging to the fifth group of clusters, and    the group-of-clusters update information computation unit computes the first group-of-clusters update information, based on the second group-of-clusters update information, the fifth group-of-clusters update information, and the fourth group-of-clusters update information.    
   
   
       6 . A data processing unit according to  claim 5 , wherein 
 the cache unit, in a case where the data elements of only a first cluster and a second cluster of the clusters are cached with respect to the second group of clusters, caches first cluster update information for the first clusters, second cluster update information for the second clusters, and sixth information of the group-of-clusters update information based on the cluster update information for all of the clusters other than the first and second clusters in the second group-of-clusters, as the group-of-clusters update information, and    the group-of-clusters update information computation unit computes the second group-of-clusters update information, based on the first cluster update information, the second cluster update information, and the sixth group-of-clusters update information.    
   
   
       7 . A data processing system according to  claim 6 , further comprising: 
 a group-of-clusters update information change unit which, in a condition where the second group-of-clusters update information and the fourth group-of-clusters update information computed by the group-of-clusters update information computation unit coincides with the second group-of-clusters update information and the fourth group-of-clusters update information acquired from the data control system respectively in a condition where the first group-of-clusters update information computed by the group-of-clusters update information computation unit does not coincide with the first group-of-clusters update information acquired from the data control system, changes the fifth group-of-clusters update information, based on the first group-of-clusters update information, the second group-of-clusters update information, and the fourth group-of-clusters update information all of which have been acquired from the data control system.    
   
   
       8 . A data processing system according to  claim 5 , wherein 
 the cluster update information stored in the data control system is obtained by converting an original data value through a hash function provided that the data element belonging to the cluster has been updated, and    the group-of-clusters update information computation unit computes the first group-of-clusters update information by performing exclusive OR operations respectively of bits corresponding to the second group-of-clusters update information, the fourth group-of-clusters update information, and the fifth group-of-clusters update information all of which are data values obtained by performing exclusive OR operations respectively of bits corresponding to the cluster update information for all of the clusters belonging to the respective groups of clusters with respect to the second group of clusters, the fourth group of clusters and the fifth group of clusters.    
   
   
       9 . A data processing system according to  claim 5 , wherein 
 the cluster update information stored in the data control system is changed into a data value obtained by performing an increment or decrement operation on an original data value, provided that the data element belonging to the cluster has been updated, and    the group-of-clusters update information computation unit computes the first group-of-clusters update information by summing the second group-of-clusters update information, the fourth group-of-clusters update information, and the fifth group-of-clusters update information all of which are data values obtained by summing the cluster update information for all of the clusters belonging to the respective groups of clusters with respect to the second group of clusters, the fourth group of clusters and the fifth group of clusters.    
   
   
       10 . A data processing system according to  claim 5 , wherein 
 each of the clusters is allocated with a cluster number,    the group of clusters consists of one cluster or two or more clusters whose cluster numbers are continuous, and    in each of the first group of clusters, the second group of clusters, and the fourth group of clusters, at least one data element is cached among data elements belonging to a cluster therein allocated with the minimum cluster number, and at least one data element is cached among data elements belonging to a cluster therein allocated with the maximum cluster number.    
   
   
       11 . A data processing system for acquiring a data element from a data control system and performing a data processing on the data element, the data control system categorizing a plurality of data elements into a plurality of clusters and storing the plurality of clusters, comprising: 
 a cache unit for acquiring from the data control system a data element belonging to a single cluster of the plurality of clusters, and cluster update information of which data value is changed when any data element belonging to the single cluster is updated, and for caching the data element and the cluster update information thus acquired;    a group-of-clusters update information computation unit for computing group-of-clusters update information pertaining to a group of clusters based on two or more pieces of the cluster update information acquired with respect to two or more of the clusters containing two or more of the data elements having been cached, the group of clusters consisting of the two or more clusters;    an update inquiry unit for transmitting to the data control system the group-of-clusters update information which is computed by the group-of-clusters update information computation unit, and for inquiring whether or not the group-of-clusters update information thus transmitted coincides with the group-of-clusters update information which is set based on two or more of the cluster update information stored in the data control system with respect to the two or more clusters; and    an update judging unit for judging that an aforementioned data element thus cached belonging to an aforementioned cluster of the group of clusters is the most updated one, in a condition where a response is received that the group-of-clusters update information which is computed by the group-of-clusters update information computation unit coincides with the group-of-clusters update information which is based on the cluster update information stored in the data control system.    
   
   
       12 . A data control system comprising: 
 a data storage unit for categorizing a plurality of data elements into a plurality of clusters and storing the plurality of clusters;    a cluster update information storage unit for storing cluster update information indicative of an update state of a data element of each of the plurality of clusters in such a way that the cluster update information is associated with the each of the plurality of clusters;    a cluster update information change unit for changing, to a different one, a data value in the cluster update information for the cluster to which the data element belongs, provided that the data element has been updated;    a data transmission unit for transmitting to a data processing system the data element and the cluster update information for the cluster to which the data element belongs in response to a request from the data processing system for acquiring the data element and performing a data processing on the data element;    a group-of-clusters update information computation unit for, in a condition where from the data processing system a referential request for the cluster update information with respect to a group of clusters consisting of two or more of the clusters is received, computing group-of-clusters update information based on the cluster update information for the two or more clusters belonging to the group of clusters; and    an update information transmission unit for transmitting the group-of-clusters update information to the data processing system.    
   
   
       13 . A data control system comprising: 
 a data storage unit for categorizing a plurality of data elements into a plurality of clusters and storing the plurality of clusters;    a cluster update information storage unit for storing cluster update information indicative of an update state of a data element of each of the plurality of clusters in such a way that the cluster update information is associated with the each of the plurality of clusters;    a cluster update information change unit for changing, to a different one, a data value in the cluster update information for the cluster to which the data element belongs, provided that the data element has been updated;    a data transmission unit for transmitting to a data processing system the data element and the cluster update information for the cluster to which the data element belongs in response to a request from the data processing system for acquiring the data element and performing a data processing on the data element;    a group-of-clusters update information receiving unit for receiving group-of-clusters update information which is computed by the data processing system based on the cluster update information with respect to a group of clusters consisting of two or more of the clusters, the cluster update information belonging to the group of clusters;    a group-of-clusters update information computation unit for computing the group-of-clusters update information based on the cluster update information stored in the cluster update information storage unit with respect to the two or more clusters; and    an update informing unit for informing the data processing system that an aforementioned data element in an aforementioned cluster belonging to the group of clusters is the most updated one, the data element having been cached in the data processing system, in a condition where the group-of-clusters update information which is computed by the group-of-clusters update information computation unit coincides with the group-of-clusters update information which is transmitted from the data processing system.    
   
   
       14 . An information system, comprising: 
 a data control system for categorizing a plurality of data elements into a plurality of clusters and storing the plurality of clusters; and    a data processing system for acquiring data from the data control system and performing a data processing on the data,    wherein the data control system comprises:    a data storage unit for categorizing a plurality of aforementioned data elements into a plurality of aforementioned clusters and storing the plurality of clusters;    a cluster update information storage unit for storing cluster update information indicative of an update state of a data element of each of the plurality of clusters in such a way that the cluster update information is associated with the each of the plurality of clusters;    a cluster update information change unit for changing, to a different one, a data value in the cluster update information for the cluster to which the data element belongs, provided that the data element has been updated;    a data transmission unit for transmitting to the data processing system the data element and the cluster update information for the cluster to which the data element belongs in response to a request from the data processing system;    a first group-of-clusters update information computation unit for, in a condition where from the data processing system a referential request for the cluster update information with respect to a group of clusters consisting of two or more of the clusters is received, computing group-of-clusters update information based on the cluster update information for the two or more clusters belonging to the group of clusters; and    an update information transmission unit for transmitting the group-of-clusters update information to the data processing system; and    the data processing system comprises:    a cache unit for acquiring from the data control system a data element belonging to a single cluster of the plurality of clusters, and the cluster update information for the single cluster, and for caching the data element and the cluster update information thus acquired;    a group-of-clusters update information acquisition unit for transmitting to the data control system the referential request with respect to a group of clusters consisting of two or more of the clusters containing two or more of the data elements having been cached, and for acquiring from the data control system group-of-clusters update information pertaining to the group of clusters;    a second group-of-clusters update information computation unit for computing the group-of-clusters update information with respect to the group of clusters based on two or more pieces of the cluster update information having been cached; and    an update judging means for judging that an aforementioned data element, having been cached, belonging to an aforementioned cluster of the group of clusters, is the most updated one, in a condition where the group-of-clusters update information computed by the second group-of-clusters update information computation unit coincides with the group-of-clusters update information acquired from the data control system.    
   
   
       15 . An information system, comprising: 
 a data control system for categorizing a plurality of data elements into a plurality of clusters and storing the plurality of clusters; and    a data processing system for acquiring data from the data control system and performing a data processing on the data,    wherein the data control system comprises:    a data storage unit for categorizing a plurality of data elements into a plurality of clusters and storing the plurality of clusters;    a cluster update information storage unit for storing cluster update information indicative of an update state of a data element of each of the plurality of clusters in such a way that the cluster update information is associated with the each of the plurality of clusters;    a cluster update information change unit for changing, to a different one, a data value in the cluster update information for the cluster to which the data element belongs, provided that the data element has been updated;    a data transmission unit for transmitting to the data processing system the data element and the cluster update information for the cluster to which the data element belongs in response to a request from the data processing system;    a group-of-clusters update information receiving unit for receiving group-of-clusters update information which is computed by the data processing system based on the cluster update information with respect to a group of clusters consisting of two or more of the clusters, the cluster update information belonging to the group of clusters;    a first group-of-clusters update information computation unit for computing the group-of-clusters update information based on the cluster update information stored in the cluster update information storage unit with respect to the two or more clusters; and    an update informing unit for informing the data processing system that an aforementioned data element in an aforementioned cluster belonging to the group of clusters is the most updated one, the data element having been cached in the data processing system, in a condition where the group-of-clusters update information which is computed by the first group-of-clusters update information computation unit coincides with the group-of-clusters update information which is transmitted from the data processing system; and    the data processing system comprises:    a cache unit for acquiring from the data control system a data element belonging to a single cluster of the plurality of clusters, and the cluster update information for the single cluster, and for caching the data element and the cluster update information thus acquired;    a second group-of-clusters update information computation unit for computing group-of-clusters update information with respect to a group of clusters based on two or more pieces of the cluster update information acquired pertaining to two or more of the clusters containing two or more of the data elements having been cached, the group of clusters consisting of the two or more clusters;    an update inquiry unit for transmitting to the data control system the group-of-clusters update information which is computed by the second group-of-clusters update information computation unit, and for inquiring whether or not the group-of-clusters update information thus transmitted coincides with the group-of-clusters update information which is set based on two or more of the cluster update information stored in the data control system with respect to the two or more clusters; and    an update judging unit for judging that an aforementioned data element thus cached belonging to an aforementioned cluster of the group of the clusters is the most updated one, in a condition where a response is received that the group-of-clusters update information which is computed by the second group-of-clusters update information computation unit coincides with the group-of-clusters update information which is based on the cluster update information stored in the data control system.    
   
   
       16 . A data processing method on a data processing system for acquiring a data element from a data control system and performing a data processing on the data element, the data control system categorizing a plurality of data elements into a plurality of clusters and storing the plurality of clusters, the data processing method comprising: 
 acquiring from the data control system a data element belonging to a single cluster of the plurality of clusters and cluster update information of which data value is changed when any data element belonging to the single cluster is updated, and caching the data element and the cluster update information thus acquired;    acquiring a group-of-clusters update information from the data control system, the group-of-clusters update information which is computed by the data control system based on two or more pieces of the cluster update information stored in the data control system with respect to two or more of the clusters containing two or more of the data elements having been cached, and the group-of-clusters update information pertaining to a group of clusters consisting of the two or more clusters;    computing a group-of-clusters update information with respect to the group of clusters based on the two or more pieces of cluster update information having been cached; and    judging that an aforementioned data element thus cached belonging to an aforementioned cluster of the group of clusters is the most updated one, in a condition where the group-of-clusters update information which is computed in the group-of-clusters update information computation step coincides with the group-of-clusters update information which is acquired from the data control system.    
   
   
       17 . A data processing method on a data processing system for acquiring a data element from a data control system and performing a data processing on the data element, the data control system categorizing a plurality of data elements into a plurality of clusters and storing the plurality of clusters, the data processing method comprising: 
 acquiring from the data control system a data element belonging to a single cluster of the plurality of clusters, and cluster update information of which data value is changed when any data element belonging to the single cluster is updated, and caching the data element and the cluster update information thus acquired;    computing a group-of-clusters update information pertaining to a group of clusters based on two or more pieces of the cluster update information acquired with respect to two or more of the clusters containing two or more of the data elements having been cached, the group of clusters consisting of the two or more clusters;    inquiring the transmission to the data control system of the group-of-clusters update information which is computed in the group-of-clusters update information computation step, and inquiring whether or not the group-of-clusters update information thus transmitted coincides with the group-of-clusters update information which is set based on two or more of the cluster update information stored in the data control system with respect to the two or more clusters; and    judging that an aforementioned data element thus cached belonging to an aforementioned cluster of the group of clusters is the most updated one, in a condition where a response is received that the group-of-clusters update information which is computed by the group-of-clusters update information computation unit coincides with the group-of-clusters update information which is based on the cluster update information stored in the data control system.    
   
   
       18 . A data processing program for a data processing system which acquires a data element from a data control system and performs a data processing on the data element, the data control system categorizing a plurality of data elements into a plurality of clusters and storing the plurality of clusters, the data processing program causing the data processing system to function as: 
 a cache unit for acquiring from the data control system a data element belonging to a single cluster of the plurality of clusters, and cluster update information of which data value is changed when any data element belonging to the single cluster is updated, and for caching the data element and the cluster update information thus acquired;    a group-of-clusters update information acquisition unit for acquiring, from the data control system, group-of-clusters update information which is computed by the data control system based on two or more pieces of the cluster update information stored in the data control system with respect to two or more of the clusters containing two or more of the data elements having been cached, the group-of-clusters update information pertaining to a group of clusters consisting of the two or more clusters;    a group-of-clusters update information computation unit for computing the group-of-clusters update information with respect to the group of clusters based on the two or more pieces of cluster update information having been cached; and    an update judging unit for judging that an aforementioned data element thus cached belonging to an aforementioned cluster of the group of clusters is the most updated one in a condition where the group-of-clusters update information which is computed by the group-of-clusters update information computation unit coincides with the group-of-clusters update information which is acquired from the data control system.    
   
   
       19 . A data processing program for a data processing system which acquires a data element from a data control system and performs a data processing on the data element, the data control system categorizing a plurality of data elements into a plurality of clusters and storing the plurality of clusters, the data processing program causing the data processing system to function as: 
 a cache unit for acquiring from the data control system a data element belonging to a single cluster of the plurality of clusters, and cluster update information of which data value is changed when any data element belonging to the single cluster is updated, and for caching the data element and the cluster update information thus acquired;    a group-of-clusters update information computation unit for computing group-of-clusters update information pertaining to a group of clusters based on two or more pieces of the cluster update information acquired with respect to two or more of the clusters containing two or more of the data elements having been cached, the group of clusters consisting of the two or more clusters;    an update inquiry unit for transmitting to the data control system the group-of-clusters update information which is computed by the group-of-clusters update information computation unit, and for inquiring whether or not the group-of-clusters update information thus transmitted coincides with the group-of-clusters update information which is set based on two or more of the cluster update information stored in the data control system with respect to the two or more clusters; and    an update judging unit for judging that an aforementioned data element thus cached belonging to an aforementioned cluster of the group of clusters is the most updated one, in a condition where a response is received that the group-of-clusters update information which is computed by the group-of-clusters update information computation unit coincides with the group-of-clusters update information which is based on the cluster update information stored in the data control system.    
   
   
       20 . A data control program for a data control system which categorizes a plurality of data elements into a plurality of clusters and stores the plurality of clusters, the data control program causing the data control system to function as: 
 a data storage unit for categorizing a plurality of data elements into a plurality of clusters and storing the plurality of clusters;    a cluster update information storage unit for storing cluster update information indicative of an update state of a data element of each of the plurality of clusters in such a way that the cluster update information is associated with the each of the plurality of clusters;    a cluster update information change unit for changing, to a different one, a data value in the cluster update information for the cluster to which the data element belongs, provided that the data element has been updated;    a data transmission unit for transmitting to a data processing system the data element and the cluster update information for the cluster to which the data element belongs in response to a request from the data processing system for acquiring the data element and performing a data processing on the data element;    a group-of-clusters update information computation unit for, in a condition where a referential request for the cluster update information with respect to a group of clusters consisting of two or more of the clusters is received from the data processing system, computing group-of-clusters update information based on the cluster update information for the two or more clusters belonging to the group of clusters; and    an update information transmission unit for transmitting the group-of-clusters update information to the data processing system.    
   
   
       21 . A data control program for a data control system which categorizes a plurality of data elements into a plurality of clusters and stores the plurality of clusters, the data control program causing the data control system to function as: 
 a data storage unit for categorizing a plurality of data elements into a plurality of clusters and storing the plurality of clusters;    a cluster update information storage unit for storing cluster update information indicative of an update state of a data element of each of the plurality of clusters in such a way that the cluster update information is associated with the each of the plurality of clusters;    a cluster update information change unit for changing, to a different one, a data value in the cluster update information for the cluster to which the data element belongs, provided that the data element has been updated;    a data transmission unit for transmitting to a data processing system the data element and the cluster update information for the cluster to which the data element belongs in response to a request from the data processing system for acquiring the data element and performing a data processing on the data element;    a group-of-clusters update information receiving unit for receiving group-of-clusters update information which is computed by the data processing system based on the cluster update information with respect to a group of clusters consisting of two or more of the clusters, the cluster update information belonging to the group of clusters;    a group-of-clusters update information computation unit for computing the group-of-clusters update information based on the cluster update information stored in the cluster update information storage unit with respect to the two or more clusters; and    an update informing unit for informing the data processing system that an aforementioned data element in an aforementioned cluster belonging to the group of clusters is the most updated one, the data element having been cached in the data processing system, in a condition where the group-of-clusters update information which is computed by the group-of-clusters update information computation unit coincides with the group-of-clusters update information which is transmitted from the data processing system.    
   
   
       22 . A computer program product comprising a computer usable medium having computer readable program code means embodied therein for causing acquirement of a data element from a data control system and performing data processing on the data element, the computer readable program code means in said computer program product comprising computer readable program code means for causing a computer to effect the functions of  claim 1 .  
   
   
       23 . A computer program product comprising a computer usable medium having computer readable program code means embodied therein for causing acquirement of a data element from a data control system and performing data processing on the data element, the computer readable program code means in said computer program product comprising computer readable program code means for causing a computer to effect the functions of  claim 11 .  
   
   
       24 . A computer program product comprising a computer usable medium having computer readable program code means embodied therein for causing functions of a data control system, the computer readable program code means in said computer program product comprising computer readable program code means for causing a computer to effect the functions of  claim 12 .  
   
   
       25 . A computer program product comprising a computer usable medium having computer readable program code means embodied therein for causing functions of an information system, the computer readable program code means in said computer program product comprising computer readable program code means for causing a computer to effect the functions of  claim 14 .  
   
   
       26 . An article of manufacture comprising a computer usable medium having computer readable program code means embodied therein for causing acquisition of a data element from a data control system and performing a data processing on the data element, the computer readable program code means in said article of manufacture comprising computer readable program code means for causing a computer to effect the steps of  claim 16