Distributed database system and a non-transitory computer readable medium
View Patent ↗A distributed database system accesses data by using management information managed by another data store, and accelerates a timing to update a data record having high access frequency. Thereby the latest data can be easily acquired. A distributed database system according to one embodiment comprises a distributed database including a plurality of nodes that stores data, and a data management device that manages the data stored in the plurality of nodes. Each of the nodes comprises a data storage unit that stores the data related to a time stamp representing a time when the data is stored and a key identifying the data, a data update unit that updates the data, a data sending unit acquires the data stored in the data storage unit, and a data update promotion unit that requests the data update unit to update the acquired data when the acquired data is not latest data.
1. A distributed database system comprising: a distributed database including a plurality of nodes that stores data; and a data management device that manages the data stored in the plurality of nodes, wherein each of the nodes comprises
a data storage unit that stores the data related to a time stamp representing a time when the data is stored, and a key identifying the data;
a data update unit that updates the data;
a data sending unit that, when a request to send data is received from a client terminal, acquires the data stored in the data storage unit; and
a data update promotion unit that requests the data update unit to update the
acquired data,
wherein the data management device comprises
a management information storage unit that stores a management information including the key and the time stamp stored in the data storage unit; and
a management information update unit that, when the data is updated in the data storage unit of any of the plurality of nodes, updates the time stamp of the updated data in the management information to a latest time stamp, and wherein the data update promotion unit:
based on a decision result whether the acquired data is latest data by using comparing the time stamp included in the acquired data with the latest time stamp of the acquired data stored in the management information storage unit, when the acquired data is not the latest data, acquires the latest data related to the latest time stamp from any other nodes in the plurality of nodes; and requests the data update unit to update the acquired data stored in the data storage unit with the latest data, wherein the management information storage unit stores the management information including an update status of the data stored in the data storage unit, the management information update unit, when the data storage unit receives an update request of the data, changes the update status to being updated, and, when update of the data is completed, changes the update status to completion, and the data sending unit does not acquire the data from the data storage unit while the update status is being updated.
2. A non-transitory computer readable medium that stores a program to be used in a distributed database system comprising
a distributed database including a plurality of nodes that stores data in respective data storage units; and
a data management device that manages the data stored in the plurality of nodes;
a management information storage unit that stores a management information including the key and the time stamp stored in the data storage unit;
a management information update unit that, when the data is updated in the data storage unit of any of the plurality of nodes, updates the time stamp of the updated data in the management information to a latest time stamp;
a data sending unit that, when a request to send data is received from a client terminal, acquires the data stored in the data storage unit;
the program causing a computer to function as:
storing the data related to a time stamp representing a time when the data is stored, and a key identifying the data, into the data storage unit; updating the data;
when a request to send data is received from a client terminal, acquiring the data stored in the data storage unit;
requesting update of the acquired data;
storing a management information including the key and the time stamp stored in the data storage unit into a management information storage unit of the data management device; and
when the data is updated in the data storage unit of any of the plurality of nodes, updating the time stamp of the updated data in the management information to a latest time stamp,
wherein the requesting includes:
based on a decision result whether the acquired data is latest data by using comparing the time stamp included in the acquired data with the latest time stamp of the acquired data stored in the management information storage unit, when the acquired data is not the latest data, acquiring the latest data related to the latest time stamp from any other nodes in the plurality of nodes; and
requesting update of the acquired data stored in the data storage unit with the latest data, wherein the management information storage unit stores the management information including an update status of the data stored in the data storage unit, the management information update unit, when the data storage unit receives an update request of the data, changes the update status to being updated, and, when update of the data is completed, changes the update status to completion, and the data sending unit does not acquire the data from the data storage unit while the update status is being updated.