Abstract: A lower-level master node sends, to a higher-level master node, a write set expanded in its own memory including a shadow copy of its own database and a heap_tuple map, and the higher-level master node that received the write set verifies whether the update has already been executed and sends the record of this update to the lower-level master node as a transaction log, whereby the database can be updated efficiently and consistently from the lower-level master node to the higher-level master node, and from the higher-level master node to the lower-level master node under its control.

Abstract: A lower-level master node sends, to a higher-level master node, a write set expanded in its own memory including a shadow copy of its own database and a heap_tuple map, and the higher-level master node that received the write set verifies whether the update has already been executed and sends the record of this update to the lower-level master node as a transaction log, whereby the database can be updated efficiently and consistently from the lower-level master node to the higher-level master node, and from the higher-level master node to the lower-level master node under its control.

Abstract: Data replication management which enables rapid retrieval while increasing the performance of the entire system, and maintaining data synchronization regarding successively updated data is performed. There are steps which comprises a step that when a slave node which has received an instruction for retrieval does not receive a return massage from a master node within a predetermined time period (Ts1) from the transmission of a request message to the master node, the slave node requests the master node to provide a transaction log up to the latest version with respect to the update of a master database; a step that the master node which has received the request transmits the transaction log to the slave node; and a step that the slave node updates a replica database with reference to the transaction log transferred from the master node.

Abstract: A multi-master node model database management technology involves notifying a higher-level master node of a transaction minimum value as a minimum value of an implementation-underway transaction in a snapshot from a lower-level master node, comparing the transaction minimum value with minimum values retained by the respective master nodes and thus updating a node minimum value and a cluster minimum value. Then, the lower-level master node transmits a write set containing a shadow copy of its own database, a heap tuple map deployed on its own memory and the transaction minimum value to the higher-level master node, and the higher-level master node receiving the write set updates the database by use of the write set if the transaction minimum value is equal to or larger than the cluster minimum value, and aborts the write set if the transaction minimum value is smaller than the cluster minimum value.

Abstract: The present invention realize a method of managing a database capable of hierarchically building master nodes, and efficiently performing the update of the master nodes. A lower-level master node sends, to a higher-level master node, a write set expanded in its own memory including a shadow copy of its own database and a heaptuple map, and the higher-level master node that received the write set verifies whether the update has already been executed and sends the record of this update to the lower-level master node as a transaction log, whereby the database can be updated efficiently and consistently from the lower-level master node to the higher-level master node, and from the higher-level master node to the lower-level master node under its control.

Abstract: Data replication management which enables rapid retrieval while increasing the performance of the entire system, and maintaining data synchronization regarding successively updated data is performed. There are steps which comprises a step that when a slave node which has received an instruction for retrieval does not receive a return massage from a master node within a predetermined time period (Ts1) from the transmission of a request message to the master node, the slave node requests the master node to provide a transaction log up to the latest version with respect to the update of a master database; a step that the master node which has received the request transmits the transaction log to the slave node; and a step that the slave node updates a replica database with reference to the transaction log transferred from the master node.