Abstract: A redundant system includes a primary system including a first node and a second node, and a secondary system including a third node and a fourth node. When the secondary system in place of the primary system operates, the fourth node executes first takeover processing or second takeover processing, the first takeover processing taking over the primary system on the basis of data update information acquired from either a second inter-system transfer path or a second intra-system transfer path, and the second takeover processing taking over the primary system on the basis of both the data update information acquired from the second inter-system transfer path and the data update information acquired from the second intra-system transfer path.

Abstract: When the redundant system operates the second node in place of the first node in the primary system and transmits, to the secondary system, data update information generated according to a data update in the second node, the fourth node the data update information generated according to the data update in the second node from the second node using the second inter-system transfer path. The fourth node changes by changing a direction of the second intra-system transfer, a configuration by which the data update information acquired by the fourth node is acquired by the third node using the second inter-system transfer path.

Abstract: A primary system includes a first node and a second node that backs up the first node. A secondary system includes a third node and a fourth node that backs up the third node. The first node transmits data update information generated in response to a data update in the first node, to the second node and the third node. The fourth node determines a degree of progress in transactions indicated by data update information obtained through the second node and a degree of progress in transactions indicated by data update information obtained through the third node, identifies data update information indicating a further progressed transaction, and reflects the data update information in stored data of the fourth node.

Abstract: A primary system includes a first node and a second node that backs up the first node. A secondary system includes a third node and a fourth node that backs up the third node. The first node in the primary system inserts, when transmitting data update information generated in response to a data update in the first node to the second node and the third node, one or a plurality of pieces of delimiter information indicating a boundary between update processing units, into both of transmit data. The fourth node in the secondary system specifies, based on the delimiter information, the data update information including update information whose process has progressed further from among the data update information obtained from the second node and the data update information obtained through the third node, and reflects the specified data update information to stored data of the fourth node.

Abstract: A disclosed data structure of a phrase tree includes, as data of each node in the phrase tree, a data block including a first area for holding a code for a character or a character string, a second area for holding, for each character that will be used, an appearance sequential number of a second character that appears next to the character or the character string, and a third area for holding, according to the appearance sequential number, a number of appearances or a code corresponding to a character string comprising the character or the character string and the second character when the number of appearances exceeds a threshold.

Abstract: A primary system includes a first node and a second node that backs up the first node. A secondary system includes a third node and a fourth node that backs up the third node. The first node in the primary system inserts, when transmitting data update information generated in response to a data update in the first node to the second node and the third node, one or a plurality of pieces of delimiter information indicating a boundary between update processing units, into both of transmit data. The fourth node in the secondary system specifies, based on the delimiter information, the data update information including update information whose process has progressed further from among the data update information obtained from the second node and the data update information obtained through the third node, and reflects the specified data update information to stored data of the fourth node.

Abstract: A redundant system includes a primary system including a first node and a second node, and a secondary system including a third node and a fourth node. When the secondary system in place of the primary system operates, the fourth node executes first takeover processing or second takeover processing, the first takeover processing taking over the primary system on the basis of data update information acquired from either a second inter-system transfer path or a second intra-system transfer path, and the second takeover processing taking over the primary system on the basis of both the data update information acquired from the second inter-system transfer path and the data update information acquired from the second intra-system transfer path.

Abstract: A primary system includes a first node and a second node that backs up the first node. A secondary system includes a third node and a fourth node that backs up the third node. The first node transmits data update information generated in response to a data update in the first node, to the second node and the third node. The fourth node determines a degree of progress in transactions indicated by data update information obtained through the second node and a degree of progress in transactions indicated by data update information obtained through the third node, identifies data update information indicating a further progressed transaction, and reflects the data update information in stored data of the fourth node.

Abstract: When the redundant system operates the second node in place of the first node in the primary system and transmits, to the secondary system, data update information generated according to a data update in the second node, the fourth node the data update information generated according to the data update in the second node from the second node using the second inter-system transfer path. The fourth node changes by changing a direction of the second intra-system transfer, a configuration by which the data update information acquired by the fourth node is acquired by the third node using the second inter-system transfer path.

Abstract: A data management apparatus includes a storage device; and a processor that executes a procedure, the procedure including selecting a data group, each data in the data group including one of a plurality of tags, among a plurality of data, compressing the data group into a compressed data group, and storing the compressed data group in the storage device, the stored compressed data group being associated with tagging information which indicates that each data of the data group includes the certain tag.

Abstract: A disclosed data structure of a phrase tree includes, as data of each node in the phrase tree, a data block including a first area for holding a code for a character or a character string, a second area for holding, for each character that will be used, an appearance sequential number of a second character that appears next to the character or the character string, and a third area for holding, according to the appearance sequential number, a number of appearances or a code corresponding to a character string comprising the character or the character string and the second character when the number of appearances exceeds a threshold.

Abstract: A data management apparatus includes a storage device; and a processor that executes a procedure, the procedure including selecting a data group, each data in the data group including one of a plurality of tags, among a plurality of data, compressing the data group into a compressed data group, and storing the compressed data group in the storage device, the stored compressed data group being associated with tagging information which indicates that each data of the data group includes the certain tag.